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Identifying Gradle Conventions

Configuration by convention has many advantages, especially in terms of conciseness because developers do not need to explicitly configure things that are implicitly configured through convention. When taking advantage of configuration by convention, however, one needs to be aware of the conventions. These conventions might be documented, but I always like it when I can programmatically determine the conventions because documentation can become outdated (same principle behind code always being correct and comments only sometimes being correct). I begin this post by looking at how to identify the specific conventions associated with the Gradle Java Plugin. I then generalize this approach to identify all properties associated with all tasks associated with the root project of a Gradle build.

The Gradle documentation on Gradle Plugins states the following regarding the importance of Gradle Plugins and what they add to a Gradle build:

Gradle at its core intentionally provides little useful functionality for real world automation. All of the useful features, such as the ability to compile Java code for example, are added by plugins. Plugins add new tasks (e.g. JavaCompile), domain objects (e.g. SourceSet), conventions (e.g. main Java source is located at src/main/java) as well as extending core objects and objects from other plugins.

This post looks at some of the tasks, domain objects, and conventions that the Java Plugin brings to a Gradle build. To start, I need a very simple Gradle build file. It consists solely of a single line that applies the Java plugin. It is shown next in the Gradle build file build-java-plugin.gradle.

build-java-plugin.gradle


apply plugin: 'java'

With that single-line Gradle build file in place, it’s easy to see which Gradle tasks the plugin-provides by running the command gradle -b build-java-plugin.gradle tasks. The next two screen snapshots show the output of running an empty Gradle build file followed by the output of running the Gradle build file with only the application of the Java plugin.

By comparing the output from running Gradle “tasks” against an empty build file to the output from running Gradle “tasks” against the build file with the Java plugin applied, we can see that the Gradle has the same set of “Build Setup tasks” and “Help tasks” whether the plugin is applied or not. More significantly, we see that the Java plugin adds many new tasks categorized as “Build tasks” (assemble, build, buildDependents, buildNeeded, classes, clean, jar, testClasses), “Documentation tasks” (javadoc), “Verification tasks” (check, test), and “Rules”.

One feature I enjoy in Gradle 1.10 that Gradle 1.8 (the previous version I used) did not have is the ability on the command line to ask for details on a specific Gradle task. This is demonstrated in the next screen snapshot for Java Plugin tasks compileJava, jar, and javadoc. All three tasks have details written to standard output by using the help --task <task_name> command on the command line. These details on the Java Plugin tasks can also be found in the Gradle User Guide.

Because Gradle is built on Groovy, it’s fairly easy to determine characteristics of the Java Plugin using “brute force.” The next code listing, for build-java-plugin-properties.gradle, demonstrates using Groovy to determine the Gradle properties (those which can be specified with -P as opposed to system properties specified with -D) available to the build script before and after applying the Java plugin and then uses Groovy’s highly convenient overridden subtraction operator to find the differences. The names and values of all of the properties added to the Gradle script by the Java Plugin (except the property “properties”) are presented in alphabetical order.


// build-java-plugin-properties.gradle
//
// Displays properties that Gradle Java Plugin adds beyond properties already
// specified for any Gradle build.

def propertiesBefore = this.properties

apply plugin: 'java'

def propertiesAfter = this.properties

def extraProperties = propertiesAfter - propertiesBefore

def extraPropertiesKeys = new TreeSet<String>()
extraProperties.each
{ property ->
if (property.key != "properties")
{
extraPropertiesKeys.add(property.key)
}
}

extraPropertiesKeys.each
{ key ->
println "${key} : ${extraProperties.get(key)}"
}

The next image shows a screen snapshot with the output from running this script. The screen snapshot does not show the full output, but a larger piece of the output (all the properties) is shown in text after the image.

Output from Running Above Gradle Script to See Java Plugin Properties


apiDocTitle : gradleExample API
archivesBaseName : gradleExample
assemble : task ':assemble'
binaries : [classes 'main', classes 'test']
build : task ':build'
buildDependents : task ':buildDependents'
buildNeeded : task ':buildNeeded'
buildTasks : [build]
check : task ':check'
classes : task ':classes'
clean : task ':clean'
compileJava : task ':compileJava'
compileTestJava : task ':compileTestJava'
defaultArtifacts : org.gradle.api.internal.plugins.DefaultArtifactPublicationSet_Decorated@bc80d8
dependencyCacheDir : C:\java\examples\groovyExamples\gradleExample\build\dependency-cache
dependencyCacheDirName : dependency-cache
distsDir : C:\java\examples\groovyExamples\gradleExample\build\distributions
distsDirName : distributions
docsDir : C:\java\examples\groovyExamples\gradleExample\build\docs
docsDirName : docs
inheritedScope : org.gradle.api.internal.ExtensibleDynamicObject$InheritedDynamicObject@c10304
jar : task ':jar'
javadoc : task ':javadoc'
libsDir : C:\java\examples\groovyExamples\gradleExample\build\libs
libsDirName : libs
manifest : org.gradle.api.java.archives.internal.DefaultManifest@1ad3677
metaInf : []
module : org.gradle.api.internal.artifacts.ProjectBackedModule@d2eead
processResources : task ':processResources'
processTestResources : task ':processTestResources'
rebuildTasks : [clean, build]
reporting : org.gradle.api.reporting.ReportingExtension_Decorated@33ab8f
reportsDir : C:\java\examples\groovyExamples\gradleExample\build\reports
reportsDirName : reports
runtimeClasspath : file collection
sourceCompatibility : 1.7
sourceSets : [source set 'main', source set 'test']
sources : [[source set 'main:java', source set 'main:resources'], [source set 'test:java', source set 'test:resources']]
status : integration
targetCompatibility : 1.7
test : task ':test'
testClasses : task ':testClasses'
testReportDir : C:\java\examples\groovyExamples\gradleExample\build\reports\tests
testReportDirName : tests
testResultsDir : C:\java\examples\groovyExamples\gradleExample\build\test-results
testResultsDirName : test-results

Gradle makes it easy to see all the Gradle properties using the command “gradle properties“, but this command line action shows all properties regardless of their source (Gradle itself or a plugin).

Each Gradle task that the Java Plugin adds to the build has its own set of properties. These properties can be identified in the Gradle Build Language Reference. The Task Types section of that document has links to each task type. The linked-to pages on each task type have details on the properties supported by that task type. For example, the Task Type JavaCompile is listed on its page as having properties such as classpath, destinationDir, and source.

The following rather extensive script displays the settings for the properties of the compileJava, jar, and javadoc Gradle Java Plugin tasks. This script demonstrates how powerful it can be to apply Groovy to identifying Gradle build settings. The script could be shorter if more reflection was used, but calling the tasks’ properties out explicitly does have advantages in terms of readability and as a reference for what properties are available on each task.

build-java-plugin-metadata.gradle


// build-java-plugin-metadata.gradle
//
// Displays the properties associated with the Gradle Java Plugin tasks
// of "compileJava", "jar", and "javadoc".

import groovy.transform.Field

apply plugin: 'java'

@Field int MAX_COLUMNS = 80
@Field String headerSeparator = "=".multiply(MAX_COLUMNS)

printCompileJavaProperties()
printJarProperties()
printJavadocProperties()

def printCompileJavaProperties()
{
printHeader("compileJava Task")
println "compileJava.classpath:\n${extractStringRepresentation(compileJava.classpath)}"
println "compileJava.destinationDir:\n${extractStringRepresentation(compileJava.destinationDir)}"
println "compileJava.source:\n${extractStringRepresentation(compileJava.source)}"
println "compileJava.options:\n${extractStringRepresentation(compileJava.options)}"
println "compileJava.includes:\n${extractStringRepresentation(compileJava.includes)}"
println "compileJava.excludes:\n${extractStringRepresentation(compileJava.excludes)}"
println "compileJava.sourceCompatibility:\n${extractStringRepresentation(compileJava.sourceCompatibility)}"
println "compileJava.targetCompatibility:\n${extractStringRepresentation(compileJava.targetCompatibility)}"
}

def printJarProperties()
{
printHeader("jar Task")
println "jar.appendix:\n${extractStringRepresentation(jar.appendix)}"
println "jar.archiveName:\n${extractStringRepresentation(jar.archiveName)}"
println "jar.archivePath:\n${extractStringRepresentation(jar.archivePath)}"
println "jar.baseName:\n${extractStringRepresentation(jar.baseName)}"
println "jar.caseSensitive:\n${extractStringRepresentation(jar.caseSensitive)}"
println "jar.classifier:\n${extractStringRepresentation(jar.classifier)}"
println "jar.destinationDir:\n${extractStringRepresentation(jar.destinationDir)}"
println "jar.dirMode:\n${extractStringRepresentation(jar.dirMode)}"
println "jar.duplicatesStrategy:\n${extractStringRepresentation(jar.duplicatesStrategy)}"
println "jar.entryCompression:\n${extractStringRepresentation(jar.entryCompression)}"
println "jar.excludes:\n${extractStringRepresentation(jar.excludes)}"
println "jar.extension:\n${extractStringRepresentation(jar.extension)}"
println "jar.fileMode:\n${extractStringRepresentation(jar.fileMode)}"
println "jar.includeEmptyDirs:\n${extractStringRepresentation(jar.includeEmptyDirs)}"
println "jar.includes:\n${extractStringRepresentation(jar.includes)}"
println "jar.manifest:\n${extractStringRepresentation(jar.manifest)}"
println "jar.source:\n${extractStringRepresentation(jar.source)}"
println "jar.version:\n${extractStringRepresentation(jar.version)}"
}

def printJavadocProperties()
{
printHeader("javadoc Task")
println "javadoc.classpath:\n${extractStringRepresentation(javadoc.classpath)}"
println "javadoc.destinationDir:\n${extractStringRepresentation(javadoc.destinationDir)}"
println "javadoc.excludes:\n${extractStringRepresentation(javadoc.excludes)}"
println "javadoc.executable:\n${extractStringRepresentation(javadoc.executable)}"
println "javadoc.failOnError:\n${extractStringRepresentation(javadoc.failOnError)}"
println "javadoc.includes:\n${extractStringRepresentation(javadoc.includes)}"
println "javadoc.maxMemory:\n${extractStringRepresentation(javadoc.maxMemory)}"
println "javadoc.options:\n${extractStringRepresentation(javadoc.options)}"
println "javadoc.source:\n${extractStringRepresentation(javadoc.source)}"
println "javadoc.title:\n${extractStringRepresentation(javadoc.title)}"
}

def String extractStringRepresentation(Object object)
{
String returnString
if (object in String)
{
returnString = "\t${object}\n"
}
else if (object in File)
{
returnString = "\t${object.canonicalPath}\n"
}
else if (object in FileCollection) // FileTree is a FileCollection
{
StringBuilder filesStr = new StringBuilder()
def files = object.files
files.each
{ file ->
filesStr << "\t" << file.canonicalPath << "\n"
}
returnString = filesStr.toString()
}
else if (object in CompileOptions)
{
StringBuilder compileOptionsStr = new StringBuilder()
def compileProperties = object.properties
compileProperties.each
{ compileProperty ->
if (compileProperty.value in DebugOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.value in DependOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.value in ForkOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.key != "class")
{
compileOptionsStr << "\t" << compileProperty.key << ": " << compileProperty.value << "\n"
}
}
returnString = compileOptionsStr.toString()
}
else if (object in DebugOptions)
{
returnString = "\t${object.debugLevel}"
}
else if (object in DependOptions)
{
returnString = "\t${object.classpath}"
}
else if (object in ForkOptions)
{
returnString = "\t${object.executable} executable with ${object.tempDir} temp directory"
}
else if (object in Set || object in Boolean || object in Number || object in Enum)
{
returnString = "\t${object.toString()}\n"
}
else if (object in Manifest)
{
StringBuilder manifestStr = new StringBuilder()
def manifestAttributes = object.getAttributes()
manifestAttributes.each
{ manifestAttribute ->
manifestStr << "\t" << manifestAttribute.key << ": " << manifestAttribute.value << "\n"
}
returnString = manifestStr.toString()
}
else if (object in MinimalJavadocOptions)
{
returnString = extractJavadocOptionsAsString(object)
}
else if (object == null)
{
returnString = "\tnull\n"
}
else
{
returnString = "\t${object?.class} was unexpected type.\n"
}
return returnString
}

def String extractJavadocOptionsAsString(MinimalJavadocOptions javadocOptions)
{
StringBuilder javadocOptionsStr = new StringBuilder()

javadocOptionsStr << "\tjavadoc.bootClasspath:"
def bootClasspathFiles = javadocOptions.bootClasspath
bootClasspathFiles.each
{ bootClasspathFile ->
javadocOptionsStr << "\t\t" << bootClasspathFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.classpath:"
def classpathFiles = javadocOptions.classpath
classpathFiles.each
{ classpathFile ->
javadocOptionsStr << "\t\t" << classpathFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.destinationDirectory: " << javadocOptions.destinationDirectory?.canonicalName << "\n"

javadocOptionsStr << "\tjavadocOptions.doclet: " << javadocOptions.doclet << "\n"

javadocOptionsStr << "\tjavadocOptions.docletpath:"
def docletpath = javadocOptions.docletpath
docletpath.each
{ docletEntry ->
javadocOptionsStr << "\t\t" << docletEntry.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.encoding: " << javadocOptions.encoding << "\n"

javadocOptionsStr << "\tjavadocOptions.extDirs:"
def extDirs = javadocOptions.extDirs
extDirs.each
{ extDir ->
javadocOptionsStr << "\t\t" << extDir.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.header: " << javadocOptions.header << "\n"

javadocOptionsStr << "\tjavadocOptions.JFlags:"
def jflags = javadocOptions.JFlags
jflags.each
{ jflag ->
javadocOptionsStr << "\t\t" << jflag << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.locale: " << javadocOptions.locale << "\n"

javadocOptionsStr << "\tjavadocOptions.memberLevel: " << javadocOptions.memberLevel << "\n"

javadocOptionsStr << "\tjavadocOptions.optionFiles:"
def optionFiles = javadocOptions.optionFiles
optionFiles.each
{ optionFile ->
javadocOptionsStr << "\t\t" << optionFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.outputLevel: " << javadocOptions.outputLevel << "\n"

javadocOptionsStr << "\tjavadocOptions.overview: " << javadocOptions.overview << "\n"

javadocOptionsStr << "\tjavadocOptions.source: " << javadocOptions.source << "\n"

javadocOptionsStr << "\tjavadocOptions.sourceNames:"
def sourceNames = javadocOptions.sourceNames
sourceNames.each
{ sourceName ->
javadocOptionsStr << "\t\t" << sourceName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.windowTitle: " << javadocOptions.windowTitle << "\n"

return javadocOptionsStr.toString()
}

def printHeader(String headerText)
{
println headerSeparator
println "= ${headerText.center(MAX_COLUMNS-4)} ="
println headerSeparator
}

I used the Groovy @Field annotation in this build file to make the variable to which it was applied available to methods in the build file. The @Field annotation was not available until Groovy 1.8 and this reminded me of something else significant to point out about Gradle and Groovy here: Gradle uses its own prepackaged Groovy rather than any other version of Groovy that might be installed on one’s machine. You can determine which version of Groovy that is with the gradle --version command. The next screen snapshot demonstrates that my version of Groovy (2.1.6) is different than the version of Groovy (1.8.6) used by my installation of Gradle (Gradle 1.10). Because Gradle 1.10 comes with Groovy 1.8.6, I had the @Field annotation at my disposal.

Because the output from the last script is so lengthy, I show it here as text rather than in an image.

Output of Running Gradle on build-java-plugin-metadata.gradle


================================================================================
= compileJava Task =
================================================================================
compileJava.classpath:

compileJava.destinationDir:
C:\java\examples\groovyExamples\gradleExample\build\classes\main

compileJava.source:
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main2.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main3.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main4.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Temperature.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureScale.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit2.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit3.java

compileJava.options:
bootClasspath: null
fork: false
encoding: null
deprecation: false
warnings: true
forkOptions: null executable with null temp directory
failOnError: true
useDepend: false
includeJavaRuntime: false
useAnt: false
compilerArgs: []
debug: true
extensionDirs: null
compiler: null
debugOptions: null
verbose: false
optimize: false
dependOptions:
listFiles: false

compileJava.includes:
[]

compileJava.excludes:
[]

compileJava.sourceCompatibility:
1.7

compileJava.targetCompatibility:
1.7

================================================================================
= jar Task =
================================================================================
jar.appendix:
null

jar.archiveName:
gradleExample.jar

jar.archivePath:
C:\java\examples\groovyExamples\gradleExample\build\libs\gradleExample.jar

jar.baseName:
gradleExample

jar.caseSensitive:
true

jar.classifier:


jar.destinationDir:
C:\java\examples\groovyExamples\gradleExample\build\libs

jar.dirMode:
null

jar.duplicatesStrategy:
INCLUDE

jar.entryCompression:
DEFLATED

jar.excludes:
[]

jar.extension:
jar

jar.fileMode:
null

jar.includeEmptyDirs:
true

jar.includes:
[]

jar.manifest:
Manifest-Version: 1.0

jar.source:
C:\java\examples\groovyExamples\gradleExample\build\tmp\jar\MANIFEST.MF

jar.version:
null

================================================================================
= javadoc Task =
================================================================================
javadoc.classpath:
C:\java\examples\groovyExamples\gradleExample\build\classes\main
C:\java\examples\groovyExamples\gradleExample\build\resources\main

javadoc.destinationDir:
C:\java\examples\groovyExamples\gradleExample\build\docs\javadoc

javadoc.excludes:
[]

javadoc.executable:
null

javadoc.failOnError:
true

javadoc.includes:
[]

javadoc.maxMemory:
null

javadoc.options:
javadoc.bootClasspath:
javadocOptions.classpath:
javadocOptions.destinationDirectory: null
javadocOptions.doclet: null
javadocOptions.docletpath:
javadocOptions.encoding: null
javadocOptions.extDirs:
javadocOptions.header: null
javadocOptions.JFlags:
javadocOptions.locale: null
javadocOptions.memberLevel: null
javadocOptions.optionFiles:
javadocOptions.outputLevel: QUIET
javadocOptions.overview: null
javadocOptions.source: null
javadocOptions.sourceNames:
javadocOptions.windowTitle: null

javadoc.source:
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main2.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main3.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Main4.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\Temperature.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureScale.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit2.java
C:\java\examples\groovyExamples\gradleExample\src\main\java\dustin\examples\TemperatureUnit3.java

javadoc.title:
gradleExample API

:help

Welcome to Gradle 1.10.

To run a build, run gradle ...

To see a list of available tasks, run gradle tasks

To see a list of command-line options, run gradle --help

BUILD SUCCESSFUL

Total time: 14.041 secs

The example shown above works well for identifying specific properties associated with the Java Gradle plugin. This works fine, but its limitations include the need to write explicit code for each property whose value is desired. This implies further limitations of not necessarily knowing all the properties that are available (I used the documentation to explicitly print out values in the example above). A further implied limitation is that the script above will not display any properties values that are added to those tasks in the future. The next Gradle build example is based on the previous example, but this example does not explicitly state the tasks and properties to display. Instead, it finds all Tasks associated with the root project and then prints all properties associated with each of those Tasks.

build-java-plugin-metadata-reflection.gradle


// build-java-plugin-metadata-reflection.gradle
//
// Displays the properties associated with the tasks associated with the Gradle
// root project.
//

import groovy.transform.Field

apply plugin: 'java'

@Field int MAX_COLUMNS = 80
@Field String headerSeparator = "=".multiply(MAX_COLUMNS)

def rootProject = getRootProject()
def tasks = rootProject.tasks
tasks.each
{ task ->
printTaskProperties(task)
}


def printTaskProperties(Task task)
{
printHeader("Task " + task.name)
def taskProperties = task.properties
taskProperties.each
{ taskProperty ->
println "${task.name}.${taskProperty.key}=${extractStringRepresentation(taskProperty.value)}"
}
}

def String extractStringRepresentation(Object object)
{
String returnString
if (object in String)
{
returnString = "\t${object}\n"
}
else if (object in File)
{
returnString = "\t${object.canonicalPath}\n"
}
else if (object in FileCollection) // FileTree is a FileCollection
{
StringBuilder filesStr = new StringBuilder()
def files = object.files
files.each
{ file ->
filesStr << "\t" << file.canonicalPath << "\n"
}
returnString = filesStr.toString()
}
else if (object in CompileOptions)
{
StringBuilder compileOptionsStr = new StringBuilder()
def compileProperties = object.properties
compileProperties.each
{ compileProperty ->
if (compileProperty.value in DebugOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.value in DependOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.value in ForkOptions)
{
compileOptionsStr << "\t" << compileProperty.key << ": " << extractStringRepresentation(compileProperty.value) << "\n"
}
else if (compileProperty.key != "class")
{
compileOptionsStr << "\t" << compileProperty.key << ": " << compileProperty.value << "\n"
}
}
returnString = compileOptionsStr.toString()
}
else if (object in DebugOptions)
{
returnString = "\t${object.debugLevel}"
}
else if (object in DependOptions)
{
returnString = "\t${object.classpath}"
}
else if (object in ForkOptions)
{
returnString = "\t${object.executable} executable with ${object.tempDir} temp directory"
}
else if (object in Set || object in List || object in Boolean || object in Number || object in Enum || object in Class)
{
returnString = "\t${object.toString()}\n"
}
else if (object in Manifest)
{
StringBuilder manifestStr = new StringBuilder()
def manifestAttributes = object.getAttributes()
manifestAttributes.each
{ manifestAttribute ->
manifestStr << "\t" << manifestAttribute.key << ": " << manifestAttribute.value << "\n"
}
returnString = manifestStr.toString()
}
else if (object in MinimalJavadocOptions)
{
returnString = extractJavadocOptionsAsString(object)
}
else if (object in Convention)
{
StringBuilder conventionStr = new StringBuilder()
object.plugins.each?.keyset
{ plugin ->
conventionStr << "\t" << plugin << "\n"
}
returnString = conventionStr.toString()
}
else if (object in LoggingManager)
{
returnString = "\n\tCurrent Log Level: ${object.level}\n\tStandard Error: ${object.standardErrorCaptureLevel}\n\tStandard Output: ${object.standardOutputCaptureLevel}\n"
}
else if (object == null)
{
returnString = "\tnull\n"
}
else
{
returnString = "\t${object?.class} was unexpected type with value of ${object}.\n"
}
return returnString
}

def String extractJavadocOptionsAsString(MinimalJavadocOptions javadocOptions)
{
StringBuilder javadocOptionsStr = new StringBuilder()

javadocOptionsStr << "\tjavadoc.bootClasspath:"
def bootClasspathFiles = javadocOptions.bootClasspath
bootClasspathFiles.each
{ bootClasspathFile ->
javadocOptionsStr << "\t\t" << bootClasspathFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.classpath:"
def classpathFiles = javadocOptions.classpath
classpathFiles.each
{ classpathFile ->
javadocOptionsStr << "\t\t" << classpathFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.destinationDirectory: " << javadocOptions.destinationDirectory?.canonicalName << "\n"

javadocOptionsStr << "\tjavadocOptions.doclet: " << javadocOptions.doclet << "\n"

javadocOptionsStr << "\tjavadocOptions.docletpath:"
def docletpath = javadocOptions.docletpath
docletpath.each
{ docletEntry ->
javadocOptionsStr << "\t\t" << docletEntry.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.encoding: " << javadocOptions.encoding << "\n"

javadocOptionsStr << "\tjavadocOptions.extDirs:"
def extDirs = javadocOptions.extDirs
extDirs.each
{ extDir ->
javadocOptionsStr << "\t\t" << extDir.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.header: " << javadocOptions.header << "\n"

javadocOptionsStr << "\tjavadocOptions.JFlags:"
def jflags = javadocOptions.JFlags
jflags.each
{ jflag ->
javadocOptionsStr << "\t\t" << jflag << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.locale: " << javadocOptions.locale << "\n"

javadocOptionsStr << "\tjavadocOptions.memberLevel: " << javadocOptions.memberLevel << "\n"

javadocOptionsStr << "\tjavadocOptions.optionFiles:"
def optionFiles = javadocOptions.optionFiles
optionFiles.each
{ optionFile ->
javadocOptionsStr << "\t\t" << optionFile.canonicalName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.outputLevel: " << javadocOptions.outputLevel << "\n"

javadocOptionsStr << "\tjavadocOptions.overview: " << javadocOptions.overview << "\n"

javadocOptionsStr << "\tjavadocOptions.source: " << javadocOptions.source << "\n"

javadocOptionsStr << "\tjavadocOptions.sourceNames:"
def sourceNames = javadocOptions.sourceNames
sourceNames.each
{ sourceName ->
javadocOptionsStr << "\t\t" << sourceName << "\n"
}
javadocOptionsStr << "\n"

javadocOptionsStr << "\tjavadocOptions.windowTitle: " << javadocOptions.windowTitle << "\n"

return javadocOptionsStr.toString()
}

def printHeader(String headerText)
{
println headerSeparator
println "= ${headerText.center(MAX_COLUMNS-4)} ="
println headerSeparator
}

Because this output is for all properties associated with all Tasks associated with the Gradle build’s root project, the output is too lengthy to include here. Not all of the property value instances have classes that the extractStringRepresentation(Object object) method is prepared to handle, but those cases could be added to the if-else if structure of that method to handle them. This version of the Gradle build is more generic than the earlier one and prints out properties associated with Tasks that are grouped by Task.

Because a Gradle build is tightly coupled to Groovy, Groovy syntax and features can be used to learn more about the Gradle build. The examples in this post took advantage of numerous Groovy niceties. The reason that the Gradle build code above is so verbose is because most of the Gradle classes used for property values do NOT have overridden toString() methods and so no really useful output is shown without special code to call specific methods to get useful representations. I didn’t do it in this post’s examples, but another option to deal with lack of overridden toString() methods would be to use Groovy’s interception capabilities (metaClass.invokeMethod) to intercept calls to toString() and provide an overridden version. That would be essentially the same code as used above, but would be encapsulated in the intercepting objects rather than contained in the script code.

Conclusion

Gradle has really nice documentation (especially the Gradle User Guide and the Gradle Build Language Reference) and most of the tasks and properties associated with the Java Plugin for Gradle (and other plugins) are easily accessible from that documentation. However, I like to know how to programmatically identify important conventions in case the documentation is ever mistaken or I use a version different than the documentation supports. Another objective of this post has been to demonstrate how useful it can be to know Groovy when working with Gradle. It is for this reason that I believe that the rising prominence of Gradle cannot help but increase interest in Groovy.

Original posting available at http://marxsoftware.blogspot.com/ (Inspired by Actual Events)

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Book Review: Groovy 2 Cookbook

I was excited to review Groovy 2 Cookbook (Packt Publishing, 2013) by Andrey Adamovich and Luciano Fiandesio because I have been very happy with two other cookbook-style Groovy books (Groovy Recipes: Greasing the Wheels of Java [Pragmatic Programmers, … Continue reading

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Significant Software Development Developments of 2013

At the end of each calendar year, I like to summarize some of the most significant developments in the software development industry that happened during the year that is ending. The choice of these is entirely subjective and obviously colored by my own experience, background, perceptions, and preferences. Not worrying about the opinionated content of such a post, I now present the developments in software development that I consider most significant in 2013.

10. Gradle

Gradle appeared to me to enter the mainstream consciousness of software developers in a big way in 2013. I have been watching Gradle’s development and playing with it a bit for some time now, but I have noticed that numerous open source projects now mention it prominently, it’s referenced in many recently published Java books that aren’t even about Gradle specifically, and Google selected Gradle to be delivered with its Android Studio product announced at Google I/O 2013. It took a while for Maven to breakthrough and compete with Ant and I think 2013 is seeing the beginning of Gradle’s breakthrough to challenge Maven and Ant for predominance in Java-based build systems. Three books devoted to Gradle (the short Gradle: Beyond the Basics, the more comprehensive Gradle in Action, and the German Gradle: Modernes Build-Management – Grundlagen und Praxiseinsatz) have listed 2013 publication dates.

Gradle‘s rapidly rising popularity is nearly matched by its torrid rate of new releases. Gradle 1.4 (“faster builds that use less heap space”), Gradle 1.5 (“optimizations to dependency resolution”), Gradle 1.6 (improved Task ordering, “JaCoCo plugin for test coverage,” and support for JUnit test categories), Gradle 1.7 (“fastest Gradle ever”), Gradle 1.8 (performance improvements and more native languages support), Gradle 1.9 (bug fixes and HTML dependency report), and Gradle 1.10 (“command-line usability features”) were all released in 2013.

Gradle’s success does not surprise me. It’s Groovy foundation alone offers numerous advantages: Groovy scripts are easier to write procedural build-style code than is XML, Groovy has numerous syntactic shortcuts, Groovy is easily learned and applied by Java developers, Groovy has full JVM access, and Groovy includes built-in Ant support. On top of its inherent advantages from being built on Groovy, Gradle builds many useful and attractive features of its own on top of that Groovy foundation. Gradle adheres to several Ant and Maven conventions and supports Ivy and Maven repositories, making it straightforward to move from Maven or Ant+Ivy to Gradle.

Ruby on Rails helped bring Ruby into mainstream international prominence and, to a lesser degree, Grails helped do the same thing for Groovy. Gradle has the potential to pick up where Grails left off and push Groovy even further into the spotlight.

9. Trend Toward Single Language Development

For several years now, there has been a definite trend toward polyglot programming (polyglot persistence was even on last year’s version of this post). Although this trend is likely to continue because some languages are better for scripting than others, some languages are better suited for web development than others, some languages are better suited for desktop development than others, some languages are better suited for realtime and embedded device development than others, some languages are better suited for scientific computing than others, and so on. However, I have seen indications of the pendulum swinging back at least a bit recently.

One of the arguments in favor of Node.js is the ability for JavaScript developers to use the same language on the “front-end” of a web application as on the “back-end.” In the post Top Things I learned about development in 2013, Antonin Januska writes, “Working back to front in the same language is awesome.” This is, of course, the reason that Java developers have in some cases been resistant to using JavaScript, Flex, or JavaFX Script (now deprecated) for front-ends of their Java applications (and why tools like Google Web Toolkit have been so popular). Java developers who write desktop applications (yes Virginia, desktop applications do exist) often experience the advantages of using the same language front-to-back as well.

One of Ceylon‘s most promising possibilities is the ability to write code in Ceylon that works on both Java Virtual Machines and JavaScript virtual machines and so could be used front-to-back in a Ceylon-based application. Indeed, the Ceylon page advertises, “[Ceylon] runs on both Java and JavaScript virtual machines, bridging the gap between client and server.” Languages commonly associated with the Java Virtual Machine such as Scala and Kotlin also are offering the ability to compile to JavaScript.

A final example of the trend back to a single language in many environments is the use of Python in scientific computing as covered in the post The homogenization of scientific computing, or why Python is steadily eating other languages’ lunch.

I’m not arguing that this trend means that there will only be one main programming language in the future. However, I do believe it is generally human nature to want to use the same language or approach as much as possible because it’s what we’re familiar with and using the same language helps us to leverage our experience more broadly in the same application. The trend seems to be for each of the major languages (C/C++, Java, JavaScript, Python, .NET languages, etc.) to continue building up their own “stack” to support end-to-end functionality within that language and its ecosystem of frameworks, libraries, and tools. It’s no coincidence that once a new language starts to see significant adoption, it quickly begins to see development of a variety of frameworks, libraries, and toolkits that extend the reach of that language.

I also don’t want to imply that this is the end of polyglot programming. I don’t see any programming language that is the best fit in all cases and there is no doubt that the most valuable developers will be those familiar with more than one programming language.

8. Internet of Things

I first heard about the concept of the Internet of Things at JavaOne 2012 and it got even more attention at JavaOne 2013. Oracle is not the only company touting the Internet of Things. IBM is into the Internet of Things as are many others.

Some believe that 2014 will be the year of the Internet of Things. Tori Wieldt has called “Java and the Internet of Things” one of the “Top Java Stories of 2013.” In 2013, two series in Hinkmond Wong’s Weblog have focused on the Internet of Things with featured posts on a Thanksgiving Turkey Tweeter and on a Christmas Santa Detector.

Other useful articles with differing opinions on the Internet of Things include The Internet of Things: a tangled web, Here’s the Scariest Part of the Internet of Things, The Internet Of Things Will Be Huge—Just Not As Huge As The Hype, Five Challenges For The Internet of Things Ecosystem, The Internet of things will not arrive in 2014, CES 2013: The Break-Out Year For The Internet Of Things, and Here’s Why ‘The Internet Of Things’ Will Be Huge, And Drive Tremendous Value For People And Businesses.

On a lighter (or more dire, depending on your perspective) note related to The Internet of Things, Aaron Pressman writes, “The whole crazy ‘Internet of Things’ movement to put everything under network control seems tailor made for Hal” (2001: A Space Odyssey).

7. Mobile Development

If someone not familiar with our industry was to start reading our software development social media sites and forums, that person would likely come to the conclusion that the vast majority of software development today is development of mobile applications. I have long argued that blog posts and articles often skew toward more leading-edge topics than established topics for a variety of reasons (perception/reality that established topics are already well-covered, resume building, fun to play with and write about new things, etc.). That being stated, there is no question that mobile development is popular in reality and not just in perception. There is no question that a big part of HTML5’s popularity and rapid adoption is the opportunity to write applications in one set of languages (HTML/JavaScript/CSS) that will run on multiple mobile devices. Numerous projects and tools are being released to allow for writing applications in one language and compiling them to native formats for various mobile devices.

6. Responsive Design

At the end of 2012, Pete Cashmore predicted that 2013 would be the “Year of Responsive Web Design” because of its “obvious benefits”: “You build a website once, and it works seamlessly across thousands of different screens.” I like Jordan Larkin‘s explanation of responsive web design:

The term “responsive web design” (or responsive mobile design) refers to websites that change and adapt their appearance for optimum viewing on all screen sizes, tablets, smartphones, ipods, kindles along with desktop and laptop computer screens. Occasionally, in the digital arts industry, it is called “fluid design”, “adaptive website design” or “RWD”. Unresponsive websites do not change to fit different screen sizes, which means they can be difficult to navigate and look at on smaller devices.

As a person who is using a smartphone for an increasing percentage of my daily online activities, but still uses the laptop frequently and the desktop occasionally, I am appreciating firsthand the web site authors whose web sites and pages work well on all of these devices. It’s often satisfactory to have two different web sites (one for mobile devices and one for everything else) from a consumer point of view, but this obviously means essentially duplicate code for the site developers. Even from a consumer point of view, there are times when I find the mobile version of a site lacking in features and in those cases it’d be preferable to have the regular site on all devices as long as that regular site appeared nicely on all devices.

The highly informative web site A List Apart has a nice set of articles related to responsive web design.

5. Node.js

JavaScript, despite its flaws, has dominated the web browser for years. Although JavaScript on the server has been available for some time (such as with Rhino and more recently Nashorn in Java), Node.js seems to be doing for JavaScript on the server what Ruby on Rails did for Ruby: the framework is popularizing the language (or in this case, popularizing the language specifically on the server).

2013 has been a big year for Node.js. There are numerous blogs and articles written on it on seemingly a daily basis. Some of these articles include What You Need To Know About Node.js and Node.js keeps stealing Rails’ thunder.

Several books on Node.js have been published in 2013. These include Node.js in Action, Learning Node.js: A Hands-On Guide to Building Web Applications in JavaScript, Node.js the Right Way: Practical, Server-Side JavaScript That Scales, Pro Node.js for Developers, Node.js Recipes: A Problem-Solution Approach, Mastering Node.js, Using Node.js for UI Testing, JavaScript on the Server Using Node.js and Express, and the final version of The Node Beginner Book.

4. Big Data

Big Data holds the same #4 spot on my list as it did last year. Apache Hadoop and the R Project are just two examples of popular products/languages riding the Big Data wave. Python too, is increasingly being chosen as the programming language of choice for working with big data sets.

Readers of java.net recently answered a survey regarding Big Data in which the closest thing to a consensus seemed to be that “Big Data Is Probably Significant, but not too Surprising.”

3. HTML5

HTML5 saw initial hype, disappointed for a while, and seems to be back on its rapid rise in popularity. I don’t call out JavaScript individually in this post, but group it with HTML and CSS as part of HTML5 (and its also grouped with Node.js in this post). Given that HTML5, for purposes of this blog post, represents all of these things, it easily makes my top three significant software development developments in 2013. As mentioned previously with regard to mobile development, HTML5 is a popular approach for generating applications once that can theoretically run on any mobile device.

HTML5 features are seeing increasing standardization in terms of implementations in major browser. JavaScript/HTML libraries such as Angular.js and Ember.js are building on the momentum that jQuery has brought to HTML5 development in recent years.

HTML5’s success is even evident in languages not considered part of HTML5 themselves. For example, one of the most heavily advertised new features of Java EE 7 is its HTML5 support. Recent versions of NetBeans IDE (considered primarily a Java IDE despite its multiple language support) have also seemed to emphasize HTML5 among their most important new features in 2013.

2. Security

As more information is online and we depend increasingly on availability of our data online, security continues to be an important issue for software developers. The trend of highly visibility security incidents continued in 2013. These incidents affected Ruby on Rails, Java, and other languages. The increasing frequency of security patches led Oracle to change how it labels the versions of Java SE.

An early 2013 article, Safeguard your code: 17 security tips for developers, outlines tips developers can take to improve the security of their applications. An earlier article in 2013 spelled out the increasing security concerns companies face. The book Java Coding Guidelines: 75 Recommendations for Reliable and Secure Programs has also been published in 2013. The 10 Biggest Security Stories Of 2013 outlines some of the biggest security-related stories of 2013.

1. Technical Dysfunction

Sadly, from a software development perspective, 2013 may be most remembered for the high profile technical glitches that occurred. Words like “debacle,” “disaster,” and “meltdown” have been associated with these issues and, rightly or wrongly, have reflected poorly on our industry. The most high profile dysfunction has been the embarrassing United States healthcare site healthcare.org. However, the issues that affect reputations and customer confidence have not been limited to government. Wal-Mart and Target, two major retailers in the United States, have had notable web site issues in the latter part of 2013 as well. Cloud-impacting technical dysfunction has occurred in 2013 in several notable cases including Amazon Web Services (AWS) and Google (including the search engine).

There seems to be plenty of blame to go around, but it seems difficult to get a good read on exactly what has caused these high profile technical failures. With healthcare.org, for example, I’ve seen people blame all types of different culprits including not allotting enough time to the effort, not being agile enough, being too agile, failing for despite agile approaches, failing to estimate user load correctly, getting government involved, etc. Although the real reasons are probably multiple and varied in nature and probably interest software developers more than others, the perception of our industry has gotten dinged up in 2013.

Honorable Mention

Although the developments in software development listed below did not make my top ten, they are significant enough to me to make this “Honorable Mention” category (in no particular or implied order).

JSON

One of the benefits of XML many years now has been the ubiquity of XML support across different languages, tools, frameworks, and libraries. For example, I recently wrote about how easy it is to use Groovy to search Subversion logs because Subversion makes its log output available in XML format and Groovy knows XML well.

JSON has been very popular with developers for some time now, but there have been many cases where standard libraries and tools that supported XML did not support JSON, meaning that developers had to write custom writing/reading code for JSON when using those libraries and tools. I’m beginning to see a lot more JSON support with tools and libraries now. Programming languages are also providing nice JSON parsing/writing capabilities. For example, Groovy has had JSON support for some time and Java EE 7 (JAX-RS 2.0) includes JSON support via the Java API for JSON.

JSON has been prominent enough in 2013 to warrant being included in titles of two Packt Publishing books published in 2013: JavaScript and JSON Essentials and Developing RESTful Services with JAX-RS 2.0, WebSockets, and JSON.

Java EE 7 Released

Java EE 7 was officially released in 2013. In a testament to Java EE’s current widespread use and expected potential use of Java EE 7, book publishers have already published several books on Java EE 7 including Java EE 7 First Look, Java EE 7 Essentials, Beginning Java EE 7, Java EE 7 Recipes: A Problem-Solution Approach, Introducing Java EE 7: A Look at What’s New, and Java EE 7 Developer Handbook.

Although I’ve never embraced JavaServer Faces (JSF), the feature of Java EE 7 that has been most interesting to me is the support for Faces Flows. I first read about this feature when reviewing Java EE 7 First Look and Neil Griffin‘s post Three Cheers for JSF 2.2 Faces Flows have reinforced my interest in this feature. In the post A Realistic JSF 2.2 Faces Flows Example, Reza Rahman supports my opinion that this is a key feature in Java EE 7 to watch with the quote, “Faces Flows are one of the best hidden gems in Java EE 7.” Michael and Faces Flows might persuade me to give JavaServer Faces another look.

A recent blog post shows integration of AngularJS with Java EE 7.

Single Page Applications

The advantage of web applications over desktop applications has always been significant easier deployment of web applications than of desktop applications. The cost, however, has been a less fluid experience and sometimes less performing application than could be provided on the desktop. The concept of single-page applications is to make web (and by extension mobile applications that use traditional web technologies) feel and behave more like a “single-page” desktop application. Newer JavaScript libraries such as Meteor are being designed for the “thicker client” style of single-page applications.

The Wikipedia page on Single Page Application lists some technical approaches to implementing this concept. The Manning book Single Page Web Applications was also released in 2013. It’s subtitle is “JavaScript end-to-end” (another piece of evidence of the general movement toward a single language).

See the description of Meteor below for another nice explanation of how web development is moving toward what is essentially this concept of single-page applications.

AngularJS

It seems like one cannot read any software development social media sites without running across mention of AngularJS. Although its Google roots are undoubtedly part of its success, AngularJS enjoys success from cleanly addressing significant needs in HTML/JavaScript development (shifting appropriate dynamic functionality from pure JavaScript to HTML with clever binding). In his post 10 Reasons Why You Should Use AngularJS, Dmitri Lau states that “Angular is the only framework that doesn’t make MVC seem like putting lipstick on a pig.” Jesus Rodriguez, in his post Why Does Angular.js Rock?, writes that AngularJS “excels in the creation of single-page-applications or even for adding some ‘magic’ to our classic web applications.” K. Scott Allen writes in his post Why Use AngularJS?, “I like Angular because I have fun writing code on top of the framework, and the framework doesn’t get in the way.”

Ember.js

Ember.js is another JavaScript library seeing significant online coverage in 2013. Ember 1.0 was released on 31 August 2013 and Ember 1.2.0 was released on 4 December 2013.

Like AngularJS and Knockout, Ember.js‘s approach is to embrace HTML and CSS rather than trying to abstract them away.

Famo.us

The famo.us web page currently requires one to “sign up for the beta” before being able to “experience famo.us.” It’s subtitle is “a JavaScript engine and framework that solve HTML5 performance.” Another famo.us page states, “famo.us is a front end framework that solves performance for HTML5 apps” and “works for phones, tablets, computers and television.”

Famo.us is discussed in two late 2013 InfoWorld posts: Did these guys just reinvent the Web? and Fast and flashy: Famo.us JavaScript framework revealed.

At this point, famo.us is still in beta, but it could be big in 2014 if it is able to deliver on what is advertised in 2013.

Meteor

Meteor is described on its main page as “an open source platform” for writing “an entire app in pure JavaScript” and using the “same APIs … on the client and the server.” In the Paul Krill interview Meteor aims to make JavaScript programming fun again, Matt DeBergalis stated that Meteor was created to address the changing web development paradigm often referred to as single-page application:

There is a shift in the Web application platform, and specifically, people are starting to write a new kind of application, what we call a thick client, where most of the code is actually running inside the Web browser itself rather than in a data center. This is an architectural change from running the software in the data center and sending HTML on the wire to a model where we have data on the wire and the actual rendering, the displaying of the user interface, is happening on the client. … That’s why it feels more interactive. It’s not page-based like the old Web. It’s much more engaging.”

MEAN Stack

Having a witty acronym helped advertise and communicate the LAMP stack (Linux, Apache HTTP Server, MySQL/MariaDB, PHP/Perl/Python) and arguably contributed to the adoption of this combination of technologies. With this in mind, I found Valeri Karpov‘s post The MEAN Stack: MongoDB, ExpressJS, AngularJS and Node.js interesting. The post’s author is another who points out the productivity advantages that can be gained from using a single language throughout an application. There is already a book underway: Getting MEAN with Mongo, Express, Angular, and Node. It will be interesting to watch this newly minted terminology and see if the stack and its name come close to the success that the LAMP stack and its name have enjoyed.

Commercial Support Dropped for GlassFish 4

Although it took longer to happen than most people probably anticipated, Oracle’s dropping of commercial support for GlassFish 4 was formally announced in 2013 and is what most of us expected when we heard of Oracle purchasing Sun. The future of GlassFish is certainly cloudier now and expectations for GlassFish’s future range from it being essentially dead to it thriving as the reference implementation.

Java IDEs

The major Java IDEs continued to add features to their already impressive feature sets in 2013. NetBeans had two major releases in 2013 with 7.3 released in February and 7.4 released in October. These two NetBeans releases added features such as Java EE 7 support, Project Easel for HTML5 development, Groovy 2.0 integration, JSON support, support for new JavaScript libraries (including Angular.js), native Java application packaging, Cordova integration, and improved support for non-JVM languages C/C++ and PHP.

IntelliJ IDEA 13 was released earlier this month. The release announcement highlights support for Java EE 7, improved Spring Framework integration, improved Android support thanks to IntelliJ IDEA Community Edition being used as the basis for Android Studio, improved database handling, and “refined Gradle support.” Eclipse is often the IDE chosen for building a more specialized IDE such as Spring IDE (Spring Tool Suite), Scala IDE, or the new Ceylon IDE, so it’s a particularly big deal that Google chose IntelliJ IDEA as the basis of its Android Studio.

Speaking of Eclipse, the seemingly most used Java-based IDE (especially when you consider the IDEs derived from it or based on it) also saw new releases in 2013. Eclipse 4.3 (Kepler) was released in 2013. There were also numerous popular plugins for Eclipse released in 2013.

Visual Studio 2013

Sun Microsystems was not the only company that saw desirable advantages and benefits from a single language that could be used at all layers of an application. Microsoft has implemented various efforts (Silverlight) for years to do the same thing. In 2013, Visual Studio 2013 was released with significant enhancements. These enhancements included improved support for languages not specific to Microsoft’s .NET framework. Many of these better supported languages are on my list in this post: JavaScript, HTML, CSS, and Python.

Groovy

Groovy’s 2.0 release (including static compilation support) made 2012 a big year for Groovy. Although 2013 did not see as significant of enhancements in the Groovy language, the year did start out with the announcement of Groovy 2.1. Perhaps the biggest part of that 2.1 release was Groovy’s full incorporation of Java SE 7‘s invokedynamic, a major Java SE enhancement intended for non-Java languages like Groovy.

Groovy 2.2’s release was announced toward the end of 2013. This release improved Groovy’s invokedynamic support by adding OSGi manifests to the Groovy’s invokedynamic-based JARs.

In The Groovy Conundrum, Andrew Binstock writes that “with the performance issues behind it, Groovy is a language primed for widespread use,” but warns that Groovy is a language that is “easy to learn, but hard to master.”

As is mentioned more than once in this post, Groovy has had a lot of additional exposure in 2013 thanks to Gradle’s rapidly rising popularity. I believe that Gradle will continue to introduce Groovy to developers not familiar with Groovy or will motivate developers who have not looked at Groovy for some time to look at it again.

Scala

It seems to me that Scala continues to gain popularity among Java developers. I continue to see Scala enthusiasts gushing about Scala on various Java and JVM blog comments and forums. One piece of evidence of Scala’s continuing and increasing popularity is the number of new books published in 2013 with Scala in their title. These include Scala in Action, Scala Cookbook: Recipes for Object-Oriented and Functional Programming, Functional Programming Patterns in Scala and Clojure: Write Lean Programs for the JVM, Scala Design Patterns: Patterns for Practical Reuse and Design, Play for Scala, Scala Object-Oriented Programming, and Getting Started with SBT for Scala.

For a much better background on what made 2013 a big year for Scala, see Jan Machacek‘s This Year in Scala (2013).

Ceylon

November 2013 saw “the first production release of the Ceylon language specification, compiler, and IDE.” This announcement, available online at Ceylon 1.0.0 is now available, also states, “Ceylon 1.0 is a modern, modular, statically typed programming language for the Java and JavaScript virtual machines.” Ceylon offers an Elipse-based IDE and has a formal specification. One of the factors favoring a successful future for Ceylon is its Red Hat sponsorship.

Kotlin

Kotlin is another language that compiles to the Java Virtual Machine or to a JavaScript virtual machine. It also has a strong sponsor in the world of Java in JetBrains, the company behind IntelliJ IDEA. 2013 saw several new releases of Kotlin: Kotlin M5.1, Kotlin M6, Kotlin M6.1, and Kotlin M6.2. I found the blog post Programming Android with Kotlin interesting because it demonstrates use of Kotlin and Gradle to build an Android application.

Go

The Go programming language has had strong backing from Google and continues to receive significant online coverage. Go 1.1 and Go 1.2 (with apparently improved performance) were both released in 2013. Of special interest to me is Go’s advertised source code backwards compatibility for all versions 1.x.

Camel

2013 was a big year for Apache Camel, the tool that “empowers you to define routing and mediation rules in a variety of domain-specific languages.” Camel-related developments in 2013 included the release of 2.11.0, release of 2.12.0, and release of 2.12.2. These frequent releases and the addition of a new committer and PMC member are among the signs of a healthy open source project.

The release of the Camel Essential Components (DZone Refcardz #170) kicked off 2013 for Camel. Camel got increased attention on software development social media sites in 2013. Zemian Deng‘s Getting started with Apache Camel using Java was syndicated on Java Code Geeks (as was his Apache Camel using Groovy Introduction) and Niraj Singh‘s Introduction to Apache Camel was also syndicated on Java Code Geeks. AndrejV‘s entire blog Just Did Some Code has so far (5 posts in 2013) been devoted to coverage of Camel!

Spring Boot

It’s still early to tell because Spring Boot is currently only at version 0.5, but Spring Boot has potential to be be widely adopted and used in the future. It looks like Spring Boot is inspired by and takes advantage of some of the best ideas in Ruby on Rails and Groovy and applies them to easy generation of Spring Framework-based applications.

Python

As stated earlier, Big Data is big and Python is getting a share of that Big Data action. The Continuum Analytics post Python for Big Data states, “Python is a powerful, flexible, open-source language that is easy to learn, easy to use, and has powerful libraries for data manipulation and analysis. … Python has a unique combination of being both a capable general-purpose programming language as well as being easy to use for analytical and quantitative computing.” Tal Yarkoni echoes this statement and observes that his “scientific computing toolbox been steadily homogenizing” on Python.

Python 3.3.1, Python 3.3.2, and Python 3.3.3 were all released in 2013. Cython has joined Pyrex as an alternative for easily writing C extensions with Python syntax and there is even a book on Learning Cython Programming.

The article Python 3.4.0 goes to beta with slew of new modules talks about some of the new features coming with Python 3.4.0 (beta) such as a standard enumeration construct. The article also points out that one of the biggest frustrations with Python remains: the two versions of the language (2.x and 3.x) and no easy route from 2.x to 3.x. From a Java development perspective, I find this interesting because there was a time when arguments like Bruce Eckel‘s (“People who don’t want to deal with these changes don’t upgrade, and those people tend not to upgrade anyway”) seemed logical and sensible. However, it’s not quite as easy as it sounds, particularly when one starts to realize the impact of this on the entire set of products, libraries, and frameworks written for a language that can be heavily impacted and perhaps not usable for some time if ever with the new language.

PHP and HHVM

2013 saw the formal release of the PHP 5.5.x versions: PHP 5.5.0, PHP 5.5.1, PHP 5.5.2, PHP 5.5.3, PHP 5.5.4, PHP 5.5.5, PHP 5.5.6, and PHP 5.5.7.

At the beginning of 2013, Gabriel Manricks outlined reasons Why 2013 is the Year of PHP. Specifically Manricks described tools such as Laravel (including Eloquent ORM), Composer (dependency manager, including Packagist), and PHPUnit (test-driven development in PHP).

The Facebook project HHVM (HipHop Virtual Machine for PHP) was initially released in 2010, but seemed to see a lot more attention in 2013. The original HPHPc compiler compiled PHP into C++ and was another manifestation of the drive to use a single language for authoring an application even if its compiled form was different. The availability of the open source HipHop Virtual Machine (HHVM) for PHP should help address performance issues with PHP; that is seemingly Facebook’s primary reason for developing it.

Android Studio

Android Studio was announced at Google I/O 2013 as “a new IDE that’s built with the needs of Android developers in mind” that is “based on the powerful, extensible IntelliJ IDEA Community Edition.”

Cloud Computing

Interest in cloud computing remained strong and continued to grow rapidly in 2013. Many of the other items discussed in this post (Big Data, security, technical dysfunctions, etc.) have strong relationships to cloud computing. For more on the biggest cloud stories on 2013, see The 10 Biggest Cloud Stories Of 2013.

Internet Explorer 11

I have not used Internet Explorer except when forced to for a number of years. For a long time, I used Firefox almost exclusively and in recent years I’ve used Google Chrome almost exclusively on PCs and Firefox on Linux. When I have been forced by a particular web site to use Internet Explorer, I have done reluctantly and am reminded of the much slower performance of the browser than I’m used to in terms of startup and even navigation. I have noticed over this Christmas break, however, when I had to install Internet Explorer 11 manually because the automatic process kept failing, that it’s a lot faster than even Internet Explorer 10 was. I still won’t make it my primary browser, but it’s nice that it performs much better when I do need to use it (such as to play Atari Arcade games without advertisements).

Internet Explorer 11 offers advantages for developers as well as users of the browser. Advertised benefits for developers (and by extension for users of these developers’ applications) are improved standards compatibility, new F12 developer tools,

It’s not all positive for Internet Explorer 11. Some people seem to want to downgrade to Explorer 10 and reportedly Internet Explorer 11 is presenting some problems for users of Microsoft’s own CRM application (after earlier reportedly breaking Google and Outlook access).

It surprises me a bit that the main Microsoft IE URL (http://windows.microsoft.com/en-us/internet-explorer/download-ie) referenced by the Internet Explorer 11 Guide for Developers still advertises downloading of Internet Explorer 9, a version of that browser that Google has already stated they will no longer support.

Windows 8 Not As Successful

Windows 8 seems to be experiencing similar disappointment after Windows 7 that Windows Vista experienced after Windows XP. In fact, The 10 Biggest Software Stories Of 2013 states, “So it looks like Windows 7 will become the new Windows XP — better get those downgrade rights ready.”

Raspberry Pi

The Raspberry Pi continues to catch a lot of interest (2 million had been sold as of October of this year). There were seemingly endless posts on how to do a wide variety of things with the Raspberry Pi. Some of these that stood out most to me are Premium Mathematica software free on budget Raspberry Pi, GertDuino: An Arduino for Your Raspberry Pi, How an open-source computer kit for kids based on Raspberry Pi is taking over Kickstarter, Running OpenJFX on Raspberry Pi, and Simon Ritter: Do You Like Coffee with Your dessert? Java and the Raspberry Pi.

DevOps

The 10 Biggest Software Stories Of 2013 points out that “Cisco, Google and VMware last year invested in Puppet Labs” and that “another DevOps player, Opscode, raised $32 million and changed its name to Chef, the name of its flagship product.”

Twitter Bootstrap

Bootstrap (alternatively known as Twitter Bootstrap and Twitter Blueprint) has become so popular and prevalent that there is now a popular (one of DZone’s top posts in 2013)

post stating Please stop using Twitter Bootstrap. In August 2013, two years after the public release of Bootstrap, Bootstrap 3 was released (with 3.0.3 released in December). Everybody Should Code

The conversation of whether everybody should or code write code and develop software continued in 2013. Jessica Gross’s writes about 10 places where anyone can learn to code and Megan O’Neil’s article A Start-Up Aims to Teach Anyone to Write Computer Code features one of these places (Codecademy). Kevin Lindquist writes that software development isn’t just for coders anymore. Katie Elizabeth lists the reasons why everyone should learn to code while Ch Continue reading

Posted in Database, Eclipse, General Development, GlassFish, Gradle, Groovy, IntelliJ IDEA, Java EE 7, JavaScript, JSON, NetBeans, PHP, Scala, Syndicated | Comments Off on Significant Software Development Developments of 2013

Searching Subversion Logs with Groovy

There are times when I want to quickly search a Subversion repository by author, by range of revisions, and/or by commit messages. Krzysztof Kotowicz has posted the blog post Grep Subversion log messages with svn-grep that introduces svn-grep, a bash script making use of the command line XML toolkit called xmlstarlet (xmlstarlet is also available on Windows). This is a pretty useful script in and of itself, but it gave me an idea for a Groovy-based script that could run on multiple (all JVM-supported) platforms.

searchSvnLog.groovy


#!/usr/bin/env groovy
//
// searchSvnLog.groovy
//
def cli = new CliBuilder(
usage: 'searchSvnLog.groovy -r <revision1> -p <revision2> -a <author> -s <stringInMessage>')
import org.apache.commons.cli.Option
cli.with
{
h(longOpt: 'help', 'Usage Information', required: false)
r(longOpt: 'revision1', 'First SVN Revision', args: 1, required: false)
p(longOpt: 'revision2', 'Last SVN Revision', args: 1, required: false)
a(longOpt: 'author', 'Revision Author', args: 1, required: false)
s(longOpt: 'search', 'Search String', args: 1, required: false)
t(longOpt: 'target', 'SVN target directory/URL', args: 1, required: true)
}
def opt = cli.parse(args)

if (!opt) return
if (opt.h) cli.usage()

Integer revision1 = opt.r ? (opt.r as int) : null
Integer revision2 = opt.p ? (opt.p as int) : null
if (revision1 != null && revision2 != null && revision1 > revision2)
{
println "It makes no sense to search for revisions ${revision1} through ${revision2}."
System.exit(-1)
}
String author = opt.a ? (opt.a as String) : null
String search = opt.s ? (opt.s as String) : null
String logTarget = opt.t

String command = "svn log -r ${revision1 ?: 1} ${revision2 ?: 'HEAD'} ${logTarget} --xml"
def proc = command.execute()
StringBuilder standard = new StringBuilder()
StringBuilder error = new StringBuilder()
proc.waitForProcessOutput(standard, error)
def returnedCode = proc.exitValue()
if (returnedCode != 0)
{
println "ERROR: Returned code ${returnedCode}"
}

def xmlLogOutput = standard.toString()
def log = new XmlSlurper().parseText(xmlLogOutput)
def logEntries = new TreeMap<Integer, LogEntry>()
log.logentry.each
{ svnLogEntry ->
Integer logRevision = Integer.valueOf(svnLogEntry.@revision as String)
String message = svnLogEntry.msg as String
String entryAuthor = svnLogEntry.author as String
if ( (!revision1 || revision1 <= logRevision)
&& (!revision2 || revision2 >= logRevision)
&& (!author || author == entryAuthor)
&& (!search || message.toLowerCase().contains(search.toLowerCase()))
)
{
def logEntry =
new LogEntry(logRevision, svnLogEntry.author as String,
svnLogEntry.date as String, message)
logEntries.put(logRevision, logEntry)
}
}
logEntries.each
{ logEntryRevisionId, logEntry ->
println "${logEntryRevisionId} : ${logEntry.author}/${logEntry.date} : ${logEntry.message}"
}

One thing that makes this script much easier to write is the ability of Subversion‘s log command to write its output in XML format with the –xml flag. Although XML has been the subject of significant criticism in recent years, one of the things I’ve liked about its availability is the widespread tool support for writing and reading XML. Subversion’s ability to write certain types of output in XML is a good example of this. Without XML, the script would have required custom parsing code to be written to parse the non-standard SVN log output. Because Subversion supports writing to the standard XML format for its output, any XML-aware tool can read it. In this case, I leveraged Groovy’s incredibly easy XML slurping (XML parsing) capability.

The script also uses Groovy’s enhanced (GDK) Process class as I briefly described in my recent post Sublime Simplicity of Scripting with Groovy.

Groovy’s built-in command-line support (CliBuilder) is used in the script to accept parameters for narrowing the search (such as applicable revisions, authors who committed, or strings to search the commit comments for). The one required parameter is the “target” which can be a file, directory, or URL.

The script references a Groovy class called LogEntry and the code listing for that class is shown next.

LogEntry.groovy


@groovy.transform.Canonical
class LogEntry
{
int revision
String author
String date
String message
}

That simple-looking LogEntry class is much more powerful than it might first appear. Because it’s Groovy, there are automatically setter/getter methods available for the four attributes. Thanks to the @Canonical annotation, it also supports a constructor, equals, hashCode, and toString methods. In other words, this class of under ten lines total has accessor and mutator methods as well as common class methods overridden appropriately for it.

Conclusion

Groovy offers numerous features to make script writing easier. In this post, I used an example of “searching” Subversion commits via the Subversion log command (and its --xml option) to demonstrate some of these useful Groovy scripting features (command line parameter parsing, native operating system integration, and easy XML parsing). Along the way, some of Groovy’s nice syntax advantages (closures, dynamic typing, GString value placeholders) were also used.

Original posting available at http://marxsoftware.blogspot.com/ (Inspired by Actual Events)

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Sublime Simplicity of Scripting with Groovy

Many of my blog posts are, as my blog’s title suggests, inspired by actual events. Three experiences this week have reminded me yet again of the simple simplicity of scripting with Groovy. In this post, I briefly look at each of these three events that are only related because they tie to Groovy and to scripting with Groovy.

Groovy Provides Easy Scripting for Java Developers

In the post I Use the main() Method, Bozhidar Bozhanov writes that he “[uses] a tool class with a main method” rather than scripting in Linux/bash or Windows PowerShell. Bozhanov goes explains this decision:

Java has a lot of powerful libraries that allow me to ditch the need of doing stuff in the shell or using bash scripts. And the good thing is – it’s Java, it can be versioned if needed, and it’s easy to use, with no additional learning curve, no man pages, etc.

Although I have been caught writing and maintaining Perl and have been known to use other scripting languages such as Ruby, Python, PHP, and shell/bash or PowerShell, I do also appreciate Bozhanov’s reasons for preferring a Java class with a main() function for developing tools. The JDK and JVM provide powerful and feature-rich libraries and capabilities and are familiar to me as a Java developer.

Groovy is a great scripting language for a person who is more comfortable with the JDK and JVM than with the underlying operating system. Groovy is easy for the Java developer to pick up and makes some things even easier than when written in Java. Groovy is particularly nice in providing “script-style” characteristics such as no need to write explicit objects, no need to write public static void main method definitions, no need to catch exceptions (checked or unchecked), built in command-line support, numerous useful GDK extensions of the JDK, dynamic typing, concise syntax (one-liners are extreme examples), easy access to root class loader for internal class loading, report-friendly output features, integrated Ant support, easy SQL access, easy XML parsing, improved regular expression support, and more.

One advantage of scripting with Groovy over some other scripting languages is the ability to run the Groovy scripts on any platform supporting a Java Virtual Machine.

Groovy Increases Java Knowledge

I have also blogged on using simple Java main classes to learn about the language. Earlier this week, a colleague ran into a surprising discovery related to Double.MIN_VALUE. When he asked if I knew what the value of Double.MIN_VALUE is, I told him that I don’t know off the top of my head, but then in a matter of seconds was able to tell him by running the following simple command on the command line:


groovy -e "println Double.MIN_VALUE"

The output of running this single line command was, as shown in the next screen snapshot, 4.9E-324. He asked me because he was (and now I was) surprised that it was not negative. After reading the Javadoc for Double.MIN_VALUE, this value made sense, but it was quicker for me to find the value by running that simple Groovy script than it was to access the Javadoc or even Google the question. I repeatedly find Groovy to be highly useful for quickly learning more about Java.

By the way, the Javadoc for Double.MIN_VALUE states (I added the emphasis), “A constant holding the smallest positive nonzero value of type double, 2-1074. It is equal to the hexadecimal floating-point literal 0x0.0000000000001P-1022 and also equal to Double.longBitsToDouble(0x1L).” I had assumed it was a negative number because I had never used it before and because of my previous experiences with negative values for Integer.MIN_VALUE and Long.MIN_VALUE. A great discussion on the reason for this selection of Double.MIN_VALUE (and applicable to Float.MIN_VALUE) is available on the StackOverflow thread Minimum values and Double.MIN_VALUE in Java?

Groovy Simplifies Native Integration

Although one of the advantages of scripting with Groovy is the ability to run Groovy scripts on any platform that supports a JVM, there are many times when scripts need to access the native operating system. Groovy has access to the native operating system via Java’s java.lang.Runtime and java.lang.Process. Groovy simplifies use of these classes through its GDK extension of the Process class.

The JDK Process class has a waitFor() method whose Javadoc description states (I added emphasis):

Causes the current thread to wait, if necessary, until the process represented by this Process object has terminated. This method returns immediately if the subprocess has already terminated. If the subprocess has not yet terminated, the calling thread will be blocked until the subprocess exits.

The class-level Javadoc for Process more clearly outlines the potential negative impact (I added emphasis):

Because some native platforms only provide limited buffer size for standard input and output streams, failure to promptly write the input stream or read the output stream of the subprocess may cause the subprocess to block, or even deadlock.

The excellent 2000 JavaWorld article When Runtime.exec() won’t shows examples of using Java code to write input and read output to avoid the block or deadlock, but Groovy’s Process GDK enhancement makes this far simpler to apply. For example, the Groovy GDK Process.waitForProcessOutput(Appendable, Appendable) method allows two StringBuilder instances, for example, representing standard output and standard error buffers to prevent “the process from blocking due to a full output buffer.”

The next two code listings and associated screen snapshots with the scripts’ outputs demonstrate this.

demoDeadlock.groovy – Process.waitFor() Deadlocks


#!/usr/bin/env groovy
def recursiveDirCmd = "cmd /c dir /s ${args[0]}"
println "Running command ${recursiveDirCmd}..."
def result = recursiveDirCmd.execute()
result.waitFor()
println result.in.text

demoNoDeadlock.groovy – Process.waitForProcessOutput(Appendable, Appendable) Does Not Deadlock


#!/usr/bin/env groovy
def recursiveDirCmd = "cmd /c dir /s ${args[0]}"
println "Running command ${recursiveDirCmd}..."
StringBuilder standard = new StringBuilder(450000)
StringBuilder error = new StringBuilder(450000)
def result = recursiveDirCmd.execute()
result.waitForProcessOutput(standard, error)
println standard

The above code listing and associated screen snapshots demonstrate that Groovy’s GDK extension of Process makes it easy to avoid blocking on commands executed against the underlying operating system. A good article on calling shell commands from Groovy code is Executing shell commands in Groovy.

Conclusion

Three different events this week reinforced my opinion of Groovy delivering a combination of Java’s power with Groovy’s scripting simplicity.

Original posting available at http://marxsoftware.blogspot.com/ (Inspired by Actual Events)

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Listening and Logging Ant Output in Groovy

In the comments section of my post Executing Ant Build File Targets from Groovy, CRC recently asked, “I’ve used your script and it seems to work but I could’t see any output at the console (I’m calling a echo task in build.xml), why?” This is a great q… Continue reading

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Uncompressing 7-Zip Files with Groovy and 7-Zip-JBinding

This post demonstrates a Groovy script for uncompressing files with the 7-Zip archive format. The two primary objectives of this post are to demonstrate uncompressing 7-Zip files with Groovy and the handy 7-Zip-JBinding and to call out and demonstrate … Continue reading

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Groovy Sql and Oracle ‘Invalid column index’ SQLException

There are some minor potential dangers associated with Groovy’s def keyword. The Groovy style and language feature guidelines for Java developers provides some warnings about use of def. In this blog post, I demonstrate an advantage of being more expli… Continue reading

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Escaping XML with Groovy 2.1

When posting source code to my blog, I often need to convert less than signs (<), and greater than signs (>) to their respective entity references so that they are not confused as HTML tags when the browser renders the output. I have often done t… Continue reading

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Enhanced Groovy-based JAR/Manifest Diff Tool

This brief blog post provides another Groovy script that provides simple differencing of two JAR (or WAR or EAR) files and their MANIFEST.MF files. It represents a combination of the JAR comparison script I blogged on earlier, Rick’s addition of Groovy… Continue reading

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