Make plugin register the task rather than relying on doLast and project references

Author: marko-bekhta

README.md

@@ -4,7 +4,7 @@ version-injection-plugin
 Gradle plugin used by Hibernate to inject project version into compiled classes
 
 To use you'd simply apply the plugin (after making sure it is added to your buildscript classpath):
-```
+```groovy
 buildscript {
     ...
     dependencies {
@@ -16,9 +16,12 @@ apply plugin: 'version-injection'
 ```
 
 Then, you'd configure it.  Configuration mainly involves naming the Class member to inject the project version into:
-```
+```groovy
 versionInjection {
-    into( 'com.acme.Version', 'getVersionString' )
+    version.set('version')
+    targetMembers.set(List.of(
+            member('com.acme.Version', 'getVersionString')
+    ))
 }
 ```
 

src/main/java/org/hibernate/build/gradle/inject/InjectionPlugin.java

@@ -25,7 +25,8 @@
 
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
-import org.gradle.api.Task;
+import org.gradle.api.plugins.JavaPluginExtension;
+import org.gradle.api.tasks.TaskProvider;
 
 /**
  * Mainly used to apply the InjectionAction to the main compileJava task
@@ -39,15 +40,23 @@ public class InjectionPlugin implements Plugin<Project> {
 	public void apply(Project project) {
 		project.getPluginManager().apply( "java" );
 
-		// Allow user to configure
-		final InjectionSpec injectionSpec = new InjectionSpec( project );
-		project.getExtensions().add( EXTENSION_NAME, injectionSpec );
+		final InjectionSpec injectionSpec = project.getExtensions().create( EXTENSION_NAME, InjectionSpec.class, project );
 
-		// The action to run after compilation
-		final InjectionAction injectionAction = new InjectionAction( injectionSpec );
-		final Task compileJava = project.getTasks().getByName( "compileJava" );
-		compileJava.getInputs().property( "version-injection-targets", injectionSpec.getTargetMembers() );
-		compileJava.doLast( injectionAction );
+		final TaskProvider<InjectionTask> injectionTaskProvider = project.getTasks().register(
+				InjectionTask.TASK_NAME, InjectionTask.class, task -> {
+					JavaPluginExtension javaExtension = (JavaPluginExtension) project.getExtensions().getByName( "java" );
+
+					task.getVersion().set( injectionSpec.getVersion() );
+					task.getInjectionTargets().set( injectionSpec.getTargetMembers() );
+
+					task.getClasspath().setFrom(
+							javaExtension.getSourceSets().getByName( "main" ).getOutput().getClassesDirs()
+					);
+
+					task.dependsOn( project.getTasks().named( "compileJava" ) );
+				}
+		);
+		project.getTasks().named( "classes" ).configure( classes -> classes.dependsOn( injectionTaskProvider ) );
 	}
 
 }

src/main/java/org/hibernate/build/gradle/inject/InjectionSpec.java

@@ -3,33 +3,20 @@
 import javax.inject.Inject;
 
 import org.gradle.api.Project;
-import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.provider.ListProperty;
+import org.gradle.api.provider.Property;
 
 /**
  * @author Steve Ebersole
  */
-public class InjectionSpec {
-	private final ListProperty<TargetMember> targetMembers;
+public abstract class InjectionSpec {
 
-	@Inject
-	public InjectionSpec(ObjectFactory objects) {
-		targetMembers = objects.listProperty( TargetMember.class );
-	}
+	public abstract Property<String> getVersion();
 
-	public InjectionSpec(Project project) {
-		this( project.getObjects() );
-	}
+	public abstract ListProperty<TargetMember> getTargetMembers();
 
-	public ListProperty<TargetMember> getTargetMembers() {
-		return targetMembers;
-	}
-
-	public void into(String className, String member) {
-		into( new TargetMember( className, member ) );
+	@Inject
+	public InjectionSpec(Project project) {
 	}
 
-	private void into(TargetMember targetMember) {
-		targetMembers.add( targetMember );
-	}
 }

src/main/java/org/hibernate/build/gradle/inject/InjectionAction.java renamed to src/main/java/org/hibernate/build/gradle/inject/InjectionTask.java

@@ -33,6 +33,9 @@
 import java.net.URLClassLoader;
 import java.util.ArrayList;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import javassist.ClassPool;
 import javassist.CtClass;
 import javassist.CtField;
@@ -43,64 +46,62 @@
 import javassist.bytecode.ClassFile;
 import javassist.bytecode.ConstantAttribute;
 import javassist.bytecode.FieldInfo;
-import org.gradle.api.Action;
-import org.gradle.api.Project;
-import org.gradle.api.Task;
-import org.gradle.api.tasks.SourceSet;
-import org.gradle.api.tasks.SourceSetContainer;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.gradle.api.DefaultTask;
+import org.gradle.api.file.ConfigurableFileCollection;
+import org.gradle.api.provider.ListProperty;
+import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.Input;
+import org.gradle.api.tasks.InputFiles;
+import org.gradle.api.tasks.TaskAction;
 
 /**
- * Responsible for coordinating the actual injection of project version.  Runs as a Gradle Action (doLast typically
- * to the main CompileJava task)
+ * Responsible for coordinating the actual injection of project version.
  *
  * @author Steve Ebersole
  */
-public class InjectionAction implements Action<Task> {
-	private static final Logger log = LoggerFactory.getLogger( InjectionAction.class );
+public abstract class InjectionTask extends DefaultTask {
+	static final String TASK_NAME = "injectVersion";
+	private static final Logger log = LoggerFactory.getLogger( InjectionTask.class );
 
 	private LoaderClassPath loaderClassPath;
 	private ClassPool classPool;
 
-	private final InjectionSpec injectionSpec;
+	@InputFiles
+	abstract ConfigurableFileCollection getClasspath();
 
-	public InjectionAction(InjectionSpec injectionSpec) {
-		this.injectionSpec = injectionSpec;
-	}
+	@Input
+	public abstract Property<String> getVersion();
+
+	@Input
+	public abstract ListProperty<TargetMember> getInjectionTargets();
 
-	@Override
-	public void execute(Task task) {
-		final ClassLoader runtimeScopeClassLoader = buildRuntimeScopeClassLoader( task.getProject() );
+	@TaskAction
+	public void execute() {
+		final ClassLoader runtimeScopeClassLoader = buildRuntimeScopeClassLoader();
 		loaderClassPath = new LoaderClassPath( runtimeScopeClassLoader );
 		classPool = new ClassPool( true );
 		classPool.appendClassPath( loaderClassPath );
 
-		performInjections( task.getProject() );
+		performInjections();
 	}
 
-	private ClassLoader buildRuntimeScopeClassLoader(Project project) {
+	private ClassLoader buildRuntimeScopeClassLoader() {
 		final ArrayList<URL> classPathUrls = new ArrayList<>();
-		final SourceSet mainSourceSet = project
-				.getExtensions()
-				.getByType( SourceSetContainer.class )
-				.getByName( SourceSet.MAIN_SOURCE_SET_NAME );
-		for ( File file : mainSourceSet.getRuntimeClasspath() ) {
+		getClasspath().forEach( file -> {
 			try {
 				classPathUrls.add( file.toURI().toURL() );
 			}
 			catch (MalformedURLException e) {
 				throw new InjectionException( "Could not determine artifact URL [" + file.getPath() + "]", e );
 			}
-		}
+		} );
 		return new URLClassLoader( classPathUrls.toArray( URL[]::new ), getClass().getClassLoader() );
 	}
 
-	private void performInjections(Project project) {
-		final String projectVersion = project.getVersion().toString();
+	private void performInjections() {
+		final String projectVersion = getVersion().get();
 
-		for ( TargetMember targetMember : injectionSpec.getTargetMembers().get() ) {
+		for ( TargetMember targetMember : getInjectionTargets().get() ) {
 			resolveInjectionTarget( targetMember ).inject( projectVersion );
 		}
 	}
@@ -113,7 +114,7 @@ private InjectionTarget resolveInjectionTarget(TargetMember targetMember) {
 				CtField field = ctClass.getField( targetMember.getMemberName() );
 				return new FieldInjectionTarget( targetMember, ctClass, field );
 			}
-			catch( NotFoundException ignore ) {
+			catch (NotFoundException ignore) {
 			}
 
 			// see if it is a method...
@@ -133,7 +134,7 @@ private InjectionTarget resolveInjectionTarget(TargetMember targetMember) {
 			// finally throw an exception
 			throw new InjectionException( "Unknown member [" + targetMember.getQualifiedName() + "]" );
 		}
-		catch ( Throwable e ) {
+		catch (Throwable e) {
 			throw new InjectionException( "Unable to resolve class [" + targetMember.getClassName() + "]", e );
 		}
 	}
@@ -146,14 +147,13 @@ private interface InjectionTarget {
 		 * Inject the given value per this target's strategy.
 		 *
 		 * @param value The value to inject.
-		 *
 		 * @throws org.hibernate.build.gradle.inject.InjectionException Indicates a problem performing the injection.
 		 */
 		void inject(String value);
 	}
 
 	private abstract class BaseInjectionTarget implements InjectionTarget {
-		@SuppressWarnings( {"UnusedDeclaration"})
+		@SuppressWarnings({ "UnusedDeclaration" })
 		private final TargetMember targetMember;
 		private final CtClass ctClass;
 		private final File classFileLocation;
@@ -164,7 +164,7 @@ protected BaseInjectionTarget(TargetMember targetMember, CtClass ctClass) {
 			try {
 				classFileLocation = new File( loaderClassPath.find( targetMember.getClassName() ).toURI() );
 			}
-			catch ( Throwable e ) {
+			catch (Throwable e) {
 				throw new InjectionException( "Unable to resolve class file path", e );
 			}
 		}
@@ -205,7 +205,7 @@ private class FieldInjectionTarget extends BaseInjectionTarget {
 		private FieldInjectionTarget(TargetMember targetMember, CtClass ctClass, CtField ctField) {
 			super( targetMember, ctClass );
 			this.ctField = ctField;
-			if ( ! Modifier.isStatic( ctField.getModifiers() ) ) {
+			if ( !Modifier.isStatic( ctField.getModifiers() ) ) {
 				throw new InjectionException( "Field is not static [" + targetMember.getQualifiedName() + "]" );
 			}
 		}
@@ -237,7 +237,7 @@ protected void doInjection(String value) {
 			try {
 				ctMethod.setBody( "{return \"" + value + "\";}" );
 			}
-			catch ( Throwable t ) {
+			catch (Throwable t) {
 				throw new InjectionException( "Unable to replace method body", t );
 			}
 		}

src/main/java/org/hibernate/build/gradle/inject/TargetMember.java

@@ -33,11 +33,15 @@ public class TargetMember implements Serializable {
 	private final String className;
 	private final String memberName;
 
-	public TargetMember(String className, String memberName) {
+	private TargetMember(String className, String memberName) {
 		this.className = className;
 		this.memberName = memberName;
 	}
 
+	public static TargetMember member(String className, String memberName) {
+		return new TargetMember( className, memberName );
+	}
+
 	public String getClassName() {
 		return className;
 	}