This plugin does a few things to make it easier/safer to use Java annotation processors in a Gradle build:
- it ensures the presence of configurations for your compile-time only dependencies (annotations, generally) and annotation processors, consistently across all supported Gradle versions;
- automatically configures the corresponding
JavaCompile
andGroovyCompile
tasks to make use of these configurations, when thejava
orgroovy
plugin is applied; - automatically configures IntelliJ IDEA and/or Eclipse when the
net.ltgt.apt-idea
ornet.ltgt.apt-eclipse
plugins are applied.
The plugin is published to the Plugin Portal; see instructions there: https://plugins.gradle.org/plugin/net.ltgt.apt
For each SourceSet
, three configurations are available:
<sourceSet>CompileOnly
(Gradle ≥ 2.12 already provides those configurations; note that this plugin doesn't provide a<sourceSet>CompileClasspath
like Gradle ≥ 2.12, but instead make it directly extend<sourceSet>Compile
)<sourceSet>AnnotationProcessor
, since version 0.14 (Gradle 4.6 already provides those configurations)<sourceSet>Apt
: those are provided for backwards compatibility with versions of this plugin up to 0.13, and are deprecated since version 0.14. The<sourceSet>AnnotationProcessor
configurations extend the respective<sourceSet>Apt
configurations to provide that compatibility.
As a result, the following configurations are available for any Java project:
compileOnly
, extendscompile
annotationProcessor
(andapt
)testCompileOnly
, extendstestCompile
testAnnotationProcessor
(andtestApt
)
The *Only
configurations are used to specify compile-time only dependencies such as annotations that will be processed by annotation processors. Annotation processors themselves are to be added to the annotationProcessor
and testAnnotationProcessor
configurations (or the apt
and testApt
configurations in version 0.13 and earlier).
The *Only
configurations are part of the classpath
of the JavaCompile
and GroovyCompile
tasks, whereas the apt
and testApt
configurations are turned into -processorpath
compiler arguments.
Note that up until version 0.7, if those configurations were empty, an empty processor path (-processorpath :
) would be passed to javac
; this was a breaking change compared to the normal behavior of Gradle, as it meant annotation processors wouldn't be looked up in the tasks' classpath
.
Starting with version 0.8, no -processorpath
will be passed if the <sourceSet>Apt
configuration is empty; this is to follow a proposal to add first-class support for annotation processing to Gradle proper, that has been added in Gradle 4.6.
Finally, note that those configurations don't extend each others: testCompileOnly
doesn't extend compileOnly
, and testAnnotationProcessor
doesn't extend annotationProcessor
; those configurations are only use for their respective JavaCompile
and GroovyCompile
tasks.
After applying the plugin following the above instructions, those added configurations can be used when declaring dependencies:
dependencies {
compile "com.google.dagger:dagger:2.14.1"
annotationProcessor "com.google.dagger:dagger-compiler:2.14.1"
// auto-factory contains both annotations and their processor, neither is needed at runtime
compileOnly "com.google.auto.factory:auto-factory:1.0-beta5"
annotationProcessor "com.google.auto.factory:auto-factory:1.0-beta5"
compileOnly "org.immutables:value:2.5.6:annotations"
annotationProcessor "org.immutables:value:2.5.6"
}
Starting with version 0.6, the plugin also configures GroovyCompile
tasks added when the groovy
plugin is applied.
It does not however configure annotation processing for Groovy sources, only for Java sources used in joint compilation.
To process annotations on Groovy sources, you'll have to configure your GroovyCompile
tasks; e.g.
compileGroovy {
groovyOptions.javaAnnotationProcessing = true
}
Compilation tasks are still cacheable with a few caveats:
- Only one language can be used per source set (i.e. either
src/main/java
orsrc/main/groovy
but not both), unless Groovy joint compilation is used (putting Java files insrc/main/groovy
), or tasks are configured to use distinct generated sources destination directories. - Groovy compilation tasks are only fully cacheable starting with Gradle 4.3.
In previous versions, the tasks won't be relocatable and will only be cacheable if files in the annotation processor path do not change (e.g. when using a project dependency and that project is rebuilt, even if the classes come from the build cache).
This due to a bug/limitation in Gradle preventing the plugin to rely on
options.annotationProcessorPath
, and having no mean to tell Gradle to use classpath normalization; this was fixed in Gradle 4.3.
Starting with version 0.15, the plugin provides Kotlin extensions to make configuration easier when using the Gradle Kotlin DSL.
The easiest is to import net.ltgt.gradle.apt.*
at the top of your *.gradle.kts
file.
Most APIs are the same as in Groovy, see below for differences.
IDE configuration is provided on a best-effort basis.
Starting with version 0.11, applying the net.ltgt.apt-eclipse
plugin will auto-configure the generated files to enable annotation processing in Eclipse.
In prior versions (until 0.10), that configuration would automatically happen whenever both the net.ltgt.apt
and eclipse
were applied (the new net.ltgt.apt-eclipse
plugin will also automatically apply the net.ltgt.apt
and eclipse
plugins).
From version 0.11 onwards, Eclipse annotation processing can be configured through a DSL, as an extension to the Eclipse JDT DSL (presented here with the default values):
eclipse {
jdt {
apt {
// whether annotation processing is enabled in Eclipse
// (isAptEnabled in Kotlin)
aptEnabled = compileJava.aptOptions.annotationProcessing
// where Eclipse will output the generated sources; value is interpreted as per project.file()
genSrcDir = file('.apt_generated')
// whether annotation processing is enabled in the editor
// (isReconcileEnabled in Kotlin)
reconcileEnabled = true
// a map of annotation processor options; a null value will pass the argument as -Akey rather than -Akey=value
processorOptions = compileJava.aptOptions.processorArgs
file {
whenMerged { jdtApt ->
// you can tinker with the JdtApt here
}
withProperties { properties ->
// you can tinker with the Properties here
}
}
}
}
factorypath {
plusConfigurations = [ configurations.apt, configurations.testApt ]
minusConfigurations = []
file {
whenMerged { factorypath ->
// you can tinker with the Factorypath here
}
withXml { node ->
// you can tinker with the Node here
}
}
}
}
When using Buildship, you'll have to manually run the eclipseJdtApt
and eclipseFactorypath
tasks to generate the Eclipse configuration files, then either run the eclipseJdt
task or manually enable annotation processing: in the project properties → Java Compiler → Annotation Processing, check Enable Annotation Processing
. Note that while all those tasks are depended on by the eclipse
task, that one is incompatible with Buildship, so you have to explicitly run the two or three aforementioned tasks and not run the eclipse
task.
Note that Eclipse does not distinguish main and test sources, and will process all of them using the same factory path and processor options, and the same generated source directory.
In any case, the net.ltgt.apt-eclipse
plugin (or simply eclipse
plugin up until version 0.10) has to be applied to the project.
This can be configured system-wide for all projects using the net.ltgt.apt
plugin by using an init script similar to the following:
allprojects { project ->
project.plugins.withId("net.ltgt.apt") {
// automatically apply net.ltgt.apt-eclipse whenever net.ltgt.apt is used
try {
project.apply plugin: "net.ltgt.apt-eclipse"
} catch (UnknownPluginException) {
// ignore, in case an older version of net.ltgt.apt is being used
// that doesn't come with net.ltgt.apt-eclipse.
}
}
}
Starting with version 0.11, applying the net.ltgt.apt-idea
plugin will auto-configure the generated files to enable annotation processing in IntelliJ IDEA.
In prior versions (until 0.10), that configuration would automatically happen whenever both the net.ltgt.apt
and idea
were applied (the new net.ltgt.apt-idea
plugin will also automatically apply the net.ltgt.apt
and idea
plugins).
When using the Gradle integration in IntelliJ IDEA (rather than the idea
task), it is recommended to delegate the IDE build actions to Gradle itself starting with IDEA 2016.3: https://www.jetbrains.com/help/idea/gradle.html#delegate_build_gradle
Otherwise, you'll have to manually enable annotation processing: in Settings… → Build, Execution, Deployment → Compiler → Annotation Processors, check Enable annotation processing
and Obtain processors from project classpath
(you'll have to make sure idea.module.apt.addAptDependencies
is enabled, starting with version 0.12). To mimic the Gradle behavior and generated files behavior, you can configure the production and test sources directories to build/generated/source/apt/main
and build/generated/source/apt/test
respectively and choose to Store generated sources relative to:
Module content root
.
Note that starting with IntelliJ IDEA 2016.1, and unless you delegate build actions to Gradle, you'll have to uncheck Create separate module per source set
when importing the project.
From version 0.12 onwards, IntelliJ IDEA annotation processing can be configured through a DSL, as an extension to the IDEA DSL (presented here with the default values):
idea {
project {
// experimental: whether annotation processing will be configured in the IDE; only actually used with the 'idea' task.
configureAnnotationProcessing = true
}
module {
apt {
// whether generated sources dirs are added as generated sources root
addGeneratedSourcesDirs = true
// whether the annotationProcessor/apt and testAnnotationProcessor/testApt dependencies are added as module dependencies
addAptDependencies = true
// The following are mostly internal details; you shouldn't ever need to configure them.
// whether the compileOnly and testCompileOnly dependencies are added as module dependencies
addCompileOnlyDependencies = false // defaults to true in Gradle < 2.12
// the dependency scope used for apt and/or compileOnly dependencies (when enabled above)
mainDependenciesScope = "PROVIDED" // defaults to "COMPILE" in Gradle < 3.4, or when using the Gradle integration in IntelliJ IDEA
}
}
}
If you always delegate build actions to Gradle, you can thus disable idea.module.apt.addAptDependencies
system-wide (there's unfortunately no way to detect this when importing the project in IDEA, so the plugin cannot configure itself automatically), by putting the following in an init script, e.g. ~/.gradle/init.d/apt-idea.gradle
:
allprojects { project ->
project.plugins.withType(JavaPlugin) {
project.plugins.withId("net.ltgt.apt-idea") {
project.afterEvaluate {
project.idea.module.apt.addAptDependencies = false
}
}
}
}
In any case, the net.ltgt.apt-idea
plugin (or simply idea
plugin up until version 0.10) has to be applied to the project.
This can be configured system-wide for all projects using the net.ltgt.apt
plugin by using an init script similar to the following:
allprojects { project ->
project.plugins.withId("net.ltgt.apt") {
try {
// automatically apply net.ltgt.apt-idea whenever net.ltgt.apt is used
project.apply plugin: "net.ltgt.apt-idea"
// disable addAptDependencies (if you delegate build actions to Gradle)
project.plugins.withType(JavaPlugin) {
project.afterEvaluate {
project.idea.module.apt.addAptDependencies = false
}
}
} catch (UnknownPluginException) {
// ignore, in case an older version of net.ltgt.apt is being used
// that doesn't come with net.ltgt.apt-idea.
}
}
}
Starting with version 0.8, the plugin makes many things configurable by enhancing source sets and tasks. Some of those enhancements have been added to Gradle proper, sometimes with different names. Starting with version 0.14, you're encouraged to use the built-in Gradle properties, and the equivalent ones added by this plugin are deprecated (and will emit deprecation messages to the console.)
Each source set has a few properties:
compileOnlyConfigurationName
(read-onlyString
) returning the<sourceSet>CompileOnly
configuration name (Gradle ≥ 2.12 already provides that property natively, this plugin contributes it for earlier Gradle versions)annotationProcessorConfigurationName
(read-onlyString
) returning the<sourceSet>AnnotationProcessor>
configuration name, starting with version 0.14 (Gradle ≥ 4.6 already provides that property natively, this plugin contributes it for earlier Gradle versions)aptConfigurationName
(read-onlyString
) returning the<sourceSet>Apt
configuration name, deprecated in version 0.14, replaced withannotationProcessorConfigurationName
. There's no Kotlin extension for this property.annotationProcessorPath
, aFileCollection
defaulting to the<sourceSet>AnnotationProcessor
configuration, starting with version 0.14processorpath
, aFileCollection
defaulting to the<sourceSet>Apt
configuration, deprecated in version 0.14, replaced withannotationProcessorPath
. There's no Kotlin extension for this property.
Each source set output
gains a generatedSourcesDir
property, a File
defaulting to ${project.buildDir}/generated/source/apt/${sourceSet.name}
.
Each JavaCompile
and GroovyCompile
task gains a couple properties:
generatedSourcesDestinationDir
, corresponding to the-s
compiler argument, i.e. whether (if set) and where to write sources files generated by annotation processors. This property is deprecated starting with version 0.14 when using Gradle ≥ 4.3, please useoptions.annotationProcessorGeneratedSourcesDirectory
instead. There's no Kotlin extension for this property.aptOptions
(read-only), itself with 4 properties:annotationProcessing
, aboolean
setting whether annotation processing is enabled or not; this maps to the-proc:none
compiler argument, and defaults totrue
(meaning that argument is not passed in, and annotation processing is enabled)processorpath
, aFileCollection
corresponding to the-processorpath
compiler argument; this property is deprecated starting with version 0.14 when using Gradle ≥ 3.4, please useoptions.annotationProcessorPath
insteadprocessors
, a list of annotation processor class names, mapping to the-processor
compiler argumentprocessorArgs
, a map of annotation processor options, each entry mapping to a-Akey=value
compiler argument
For each source set, the corresponding JavaCompile
and GroovyCompile
tasks are configured such that:
generatedSourcesDestinationDir
maps to the source set'soutput.generatedSourcesDir
aptOptions.processorpath
maps to the source set'sannotationProcessorPath