Add 'classifier' property to Gradle plugin

The default behaviour doesn't change with this commit, but now
the user has the option to specify a 'classifier' property
either in springBoot { classifier = 'exec' } (i.e. globally
for all repackage tasks) or in each repackage task, e.g.
bootRepackage { classifier = 'exec' }. In that case the original
archive is not overwritten but copied into <file>-<classifier>.jar
(or .war etc.) and then enhanced.

Fixes gh-1113, fixes gh-141 also I believe.

spring-boot-tools/spring-boot-gradle-plugin/src/main/groovy/org/springframework/boot/gradle/SpringBootPluginExtension.groovy

@@ -58,12 +58,20 @@ public class SpringBootPluginExtension {
 	}
 
 	/**
-	 * The main class that should be run. If not specified the value from the
-	 * MANIFEST will be used, or if no manifest entry is the archive will be
+	 * The main class that should be run. Instead of setting this explicitly you can use the 
+	 * 'mainClassName' of the project or the 'main' of the 'run' task. If not specified the 
+	 * value from the MANIFEST will be used, or if no manifest entry is the archive will be
 	 * searched for a suitable class.
 	 */
 	String mainClass
 
+	/**
+	 * The classifier (file name part before the extension). Instead of setting this explicitly 
+	 * you can use the 'classifier' property of the 'bootRepackage' task. If not specified the archive
+	 * will be replaced instead of renamed.
+	 */
+	String classifier
+
 	/**
 	 * The name of the ivy configuration name to treat as 'provided' (when packaging
 	 * those dependencies in a separate path). If not specified 'providedRuntime' will

spring-boot-tools/spring-boot-gradle-plugin/src/main/groovy/org/springframework/boot/gradle/repackage/RepackagePluginFeatures.java

@@ -16,11 +16,17 @@
 
 package org.springframework.boot.gradle.repackage;
 
+import java.io.File;
+
+import org.gradle.api.Action;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.artifacts.Dependency;
 import org.gradle.api.plugins.BasePlugin;
+import org.gradle.api.tasks.bundling.Jar;
 import org.springframework.boot.gradle.PluginFeatures;
+import org.springframework.boot.gradle.SpringBootPluginExtension;
+import org.springframework.util.StringUtils;
 
 /**
  * {@link PluginFeatures} to add repackage support.
@@ -47,9 +53,19 @@ public class RepackagePluginFeatures implements PluginFeatures {
 		task.dependsOn(project.getConfigurations()
 				.getByName(Dependency.ARCHIVES_CONFIGURATION).getAllArtifacts()
 				.getBuildDependencies());
+		registerOutput(project, task);
 		ensureTaskRunsOnAssembly(project, task);
 	}
 
+	private void registerOutput(Project project, final RepackageTask task) {
+		project.afterEvaluate(new Action<Project>() {
+			@Override
+			public void execute(Project project) {
+				project.getTasks().withType(Jar.class, new OutputAction(task));	
+			}
+		});
+	}
+
 	private void ensureTaskRunsOnAssembly(Project project, Task task) {
 		project.getTasks().getByName(BasePlugin.ASSEMBLE_TASK_NAME).dependsOn(task);
 	}
@@ -62,4 +78,51 @@ public class RepackagePluginFeatures implements PluginFeatures {
 				.set("BootRepackage", RepackageTask.class);
 	}
 
+	private class OutputAction implements Action<Jar> {
+
+		private RepackageTask task;
+
+		public OutputAction(RepackageTask task) {
+			this.task = task;
+		}
+
+		@Override
+		public void execute(Jar archive) {
+			if ("".equals(archive.getClassifier())) {
+				setClassifier(task, archive);
+				File file = archive.getArchivePath();
+				String classifier = task.getClassifier();
+				if (classifier != null) {
+					String withClassifer = file.getName();
+					withClassifer = StringUtils.stripFilenameExtension(withClassifer)
+							+ "-" + classifier + "."
+							+ StringUtils.getFilenameExtension(withClassifer);
+					File out = new File(file.getParentFile(), withClassifer);
+					file = out;
+					task.getOutputs().file(file);
+					task.setOutputFile(file);
+				}
+			}
+
+		}
+
+		private void setClassifier(RepackageTask task, Jar archive) {
+			Project project = task.getProject();
+			String classifier = null;
+			SpringBootPluginExtension extension = project.getExtensions().getByType(
+					SpringBootPluginExtension.class);
+			if (task.getClassifier() != null) {
+				classifier = task.getClassifier();
+			}
+			else if (extension.getClassifier() != null) {
+				classifier = extension.getClassifier();
+			}
+			if (classifier != null) {
+				project.getLogger().info("Setting classifier: " + classifier);
+				task.setClassifier(classifier);
+			}
+		}
+
+	}
+
 }

spring-boot-tools/spring-boot-gradle-plugin/src/main/groovy/org/springframework/boot/gradle/repackage/RepackageTask.java

@@ -27,6 +27,7 @@ import org.gradle.api.tasks.TaskAction;
 import org.gradle.api.tasks.bundling.Jar;
 import org.springframework.boot.gradle.SpringBootPluginExtension;
 import org.springframework.boot.loader.tools.Repackager;
+import org.springframework.util.FileCopyUtils;
 
 /**
  * Repackage task.
@@ -44,6 +45,10 @@ public class RepackageTask extends DefaultTask {
 
 	private String mainClass;
 
+	private String classifier;
+
+	private File outputFile;
+
 	public void setCustomConfiguration(String customConfiguration) {
 		this.customConfiguration = customConfiguration;
 	}
@@ -55,11 +60,19 @@ public class RepackageTask extends DefaultTask {
 	public void setMainClass(String mainClass) {
 		this.mainClass = mainClass;
 	}
-	
+
 	public String getMainClass() {
 		return mainClass;
 	}
 
+	public String getClassifier() {
+		return classifier;
+	}
+
+	public void setClassifier(String classifier) {
+		this.classifier = classifier;
+	}
+
 	@TaskAction
 	public void repackage() {
 		Project project = getProject();
@@ -102,13 +115,24 @@ public class RepackageTask extends DefaultTask {
 				File file = archive.getArchivePath();
 				if (file.exists()) {
 					Repackager repackager = new LoggingRepackager(file);
+					File out = RepackageTask.this.outputFile;
+					if (out != null) {
+						try {
+							FileCopyUtils.copy(file, out);
+						}
+						catch (IOException e) {
+							throw new IllegalStateException(e.getMessage(), e);
+						}
+						file = out;
+					}
+					RepackageTask.this.outputFile = file;
 					setMainClass(repackager);
 					if (this.extension.convertLayout() != null) {
 						repackager.setLayout(this.extension.convertLayout());
 					}
 					repackager.setBackupSource(this.extension.isBackupSource());
 					try {
-						repackager.repackage(this.libraries);
+						repackager.repackage(file, this.libraries);
 					}
 					catch (IOException ex) {
 						throw new IllegalStateException(ex.getMessage(), ex);
@@ -121,10 +145,13 @@ public class RepackageTask extends DefaultTask {
 			String mainClass = (String) getProject().property("mainClassName");
 			if (RepackageTask.this.mainClass != null) {
 				mainClass = RepackageTask.this.mainClass;
-			} else if (this.extension.getMainClass() != null) {
+			}
+			else if (this.extension.getMainClass() != null) {
 				mainClass = this.extension.getMainClass();
-			} else if (getProject().getTasks().getByName("run").hasProperty("main")) {
-				mainClass = (String) getProject().getTasks().getByName("run").property("main");
+			}
+			else if (getProject().getTasks().getByName("run").hasProperty("main")) {
+				mainClass = (String) getProject().getTasks().getByName("run")
+						.property("main");
 			}
 			getLogger().info("Setting mainClass: " + mainClass);
 			repackager.setMainClass(mainClass);
@@ -154,4 +181,9 @@ public class RepackageTask extends DefaultTask {
 			}
 		};
 	}
+
+	void setOutputFile(File file) {
+		this.outputFile = file;
+	}
+
 }