Java tutorial
/******************************************************************************* * Copyright (c) 2012 Red Hat, Inc. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Red Hat, Inc. - initial API and implementation *******************************************************************************/ package org.eclipse.m2e.jdt.internal; import java.util.Arrays; import java.util.LinkedHashSet; import java.util.List; import java.util.Properties; import java.util.Set; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.eclipse.core.resources.IFile; import org.eclipse.core.resources.IFolder; import org.eclipse.core.resources.IProject; import org.eclipse.core.resources.IResource; import org.eclipse.core.resources.IResourceVisitor; import org.eclipse.core.runtime.CoreException; import org.eclipse.core.runtime.IPath; import org.eclipse.core.runtime.IProgressMonitor; import org.eclipse.jdt.core.IClasspathEntry; import org.eclipse.jdt.core.IJavaProject; import org.eclipse.jdt.core.JavaCore; import org.codehaus.plexus.util.xml.Xpp3Dom; import org.apache.maven.model.Build; import org.apache.maven.model.Model; import org.apache.maven.model.Plugin; import org.apache.maven.model.Resource; import org.eclipse.m2e.core.project.conversion.AbstractProjectConversionParticipant; /** * Converts existing Eclipse Java projects by setting the maven compiler source and target values. It also tries to best * match existing Java source directories with the corresponding source, test source, resource and test resource * directories of the Maven model. * * @author Fred Bricon */ public class JavaProjectConversionParticipant extends AbstractProjectConversionParticipant { private static final Logger log = LoggerFactory.getLogger(JavaProjectConversionParticipant.class); private static final String DEFAULT_JAVA_SOURCE = "src/main/java"; //$NON-NLS-1$ private static final String DEFAULT_RESOURCES = "src/main/resources"; //$NON-NLS-1$ private static final String DEFAULT_JAVA_TEST_SOURCE = "src/test/java"; //$NON-NLS-1$ private static final String DEFAULT_TEST_RESOURCES = "src/test/resources"; //$NON-NLS-1$ private static final String DEFAULT_JAVA_VERSION = "1.5"; //$NON-NLS-1$ private static final String COMPILER_GROUP_ID = "org.apache.maven.plugins"; //$NON-NLS-1$ private static final String COMPILER_ARTIFACT_ID = "maven-compiler-plugin"; //$NON-NLS-1$ private static final String DEFAULT_COMPILER_VERSION = "3.0"; //$NON-NLS-1$ private static final String TARGET_KEY = "target"; //$NON-NLS-1$ private static final String SOURCE_KEY = "source"; //$NON-NLS-1$ private static final String CONFIGURATION_KEY = "configuration"; //$NON-NLS-1$ public boolean accept(IProject project) throws CoreException { boolean accepts = project != null && project.isAccessible() && project.hasNature(JavaCore.NATURE_ID); return accepts; } public void convert(IProject project, Model model, IProgressMonitor monitor) throws CoreException { if (!accept(project)) { return; } IJavaProject javaProject = JavaCore.create(project); if (javaProject == null) { return; } log.debug("Applying Java conversion to " + project.getName()); //$NON-NLS-1$ configureBuildSourceDirectories(model, javaProject); //Read existing Eclipse compiler settings String source = javaProject.getOption(JavaCore.COMPILER_SOURCE, false); String target = javaProject.getOption(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, false); //We want to keep pom.xml configuration to a minimum so we rely on convention. If the java version == 1.5, //we shouldn't need to add anything as recent maven-compiler-plugin versions target Java 1.5 by default if (DEFAULT_JAVA_VERSION.equals(source) && DEFAULT_JAVA_VERSION.equals(target)) { return; } //Configure Java version boolean useProperties = false;//TODO Use preferences if (useProperties) { configureProperties(model, source, target); } else { configureCompilerPlugin(model, source, target); } } private void configureProperties(Model model, String source, String target) { Properties properties = model.getProperties(); if (properties == null) { properties = new Properties(); model.setProperties(properties); } properties.setProperty("maven.compiler.source", source); //$NON-NLS-1$ properties.setProperty("maven.compiler.target", target); //$NON-NLS-1$ } private void configureCompilerPlugin(Model model, String source, String target) { Build build = getOrCreateBuild(model); model.setBuild(build); Plugin compiler = getOrCreateCompilerPlugin(build); Xpp3Dom configuration = (Xpp3Dom) compiler.getConfiguration(); if (configuration == null) { configuration = new Xpp3Dom(CONFIGURATION_KEY); compiler.setConfiguration(configuration); } Xpp3Dom sourceDom = configuration.getChild(SOURCE_KEY); if (sourceDom == null) { sourceDom = new Xpp3Dom(SOURCE_KEY); configuration.addChild(sourceDom); } sourceDom.setValue(source); Xpp3Dom targetDom = configuration.getChild(TARGET_KEY); if (targetDom == null) { targetDom = new Xpp3Dom(TARGET_KEY); configuration.addChild(targetDom); } targetDom.setValue(target); compiler.setConfiguration(configuration); } private Plugin getOrCreateCompilerPlugin(Build build) { build.flushPluginMap();//We need to force the re-generation of the plugin map as it may be stale Plugin compiler = build.getPluginsAsMap().get(COMPILER_GROUP_ID + ":" + COMPILER_ARTIFACT_ID); //$NON-NLS-1$ if (compiler == null) { compiler = build.getPluginsAsMap().get(COMPILER_ARTIFACT_ID); } if (compiler == null) { compiler = new Plugin(); compiler.setGroupId(COMPILER_GROUP_ID); compiler.setArtifactId(COMPILER_ARTIFACT_ID); compiler.setVersion(getCompilerVersion()); build.addPlugin(compiler); } return compiler; } private void configureBuildSourceDirectories(Model model, IJavaProject javaProject) throws CoreException { IClasspathEntry[] entries = javaProject.getRawClasspath(); Set<String> sources = new LinkedHashSet<String>(); Set<String> potentialTestSources = new LinkedHashSet<String>(); Set<String> potentialResourceDirectories = new LinkedHashSet<String>(); Set<String> potentialTestResourceDirectories = new LinkedHashSet<String>(); IPath projectPath = javaProject.getPath(); for (int i = 0; i < entries.length; i++) { if (entries[i].getEntryKind() == IClasspathEntry.CPE_SOURCE) { IPath path = entries[i].getPath().makeRelativeTo(projectPath); if (path.isAbsolute()) { //We only support paths relative to the project root, so we skip this one continue; } String portablePath = path.toPortableString(); boolean isPotentialTestSource = isPotentialTestSource(path); boolean isResource = false; if (isPotentialTestSource) { if (DEFAULT_TEST_RESOURCES.equals(portablePath)) { isResource = potentialTestResourceDirectories.add(portablePath); } else { potentialTestSources.add(portablePath); } } else { if (DEFAULT_RESOURCES.equals(portablePath)) { isResource = potentialResourceDirectories.add(portablePath); } else { sources.add(portablePath); } } if (!isResource) { //For source folders not already flagged as resource folder, check if // they contain non-java sources, so we can add them as resources too boolean hasNonJavaResources = false; IFolder folder = javaProject.getProject().getFolder(path); if (folder.isAccessible()) { NonJavaResourceVisitor nonJavaResourceVisitor = new NonJavaResourceVisitor(); try { folder.accept(nonJavaResourceVisitor); } catch (NonJavaResourceFoundException ex) { //Expected hasNonJavaResources = true; } catch (CoreException ex) { //385666 ResourceException is thrown in Helios if (ex.getCause() instanceof NonJavaResourceFoundException) { hasNonJavaResources = true; } else { log.error("An error occured while analysing {} : {}", folder, ex.getMessage()); } } } if (hasNonJavaResources) { if (isPotentialTestSource) { potentialTestResourceDirectories.add(portablePath); } else { potentialResourceDirectories.add(portablePath); } } } } } Build build = getOrCreateBuild(model); if (!sources.isEmpty()) { if (sources.size() > 1) { //We don't know how to handle multiple sources, i.e. how to map to a resource or test source directory //That should be dealt by setting the build-helper-plugin config (http://mojo.codehaus.org/build-helper-maven-plugin/usage.html) log.warn("{} has multiple source entries, this is not supported yet", model.getArtifactId()); //$NON-NLS-1$ } String sourceDirectory = sources.iterator().next(); if (!DEFAULT_JAVA_SOURCE.equals(sourceDirectory)) { build.setSourceDirectory(sourceDirectory); } for (String resourceDirectory : potentialResourceDirectories) { if (!DEFAULT_RESOURCES.equals(resourceDirectory) || potentialResourceDirectories.size() > 1) { build.addResource(createResource(resourceDirectory)); } } } if (!potentialTestSources.isEmpty()) { if (potentialTestSources.size() > 1) { log.warn("{} has multiple test source entries, this is not supported yet", model.getArtifactId()); //$NON-NLS-1$ } String testSourceDirectory = potentialTestSources.iterator().next(); if (!DEFAULT_JAVA_TEST_SOURCE.equals(testSourceDirectory)) { build.setTestSourceDirectory(testSourceDirectory); } for (String resourceDirectory : potentialTestResourceDirectories) { if (!DEFAULT_TEST_RESOURCES.equals(resourceDirectory) || potentialTestResourceDirectories.size() > 1) { build.addTestResource(createResource(resourceDirectory)); } } } //Ensure we don't attach a new empty build definition to the model if (build.getSourceDirectory() != null || build.getTestSourceDirectory() != null || !build.getResources().isEmpty() || !build.getTestResources().isEmpty()) { model.setBuild(build); } } private Resource createResource(String resourceDirectory) { Resource r = new Resource(); r.setDirectory(resourceDirectory); r.addExclude("**/*.java"); //$NON-NLS-1$ return r; } /** * Checks if a given path has one of its segment ending with test or tests */ private boolean isPotentialTestSource(IPath path) { for (String segment : path.segments()) { String folderName = segment.toLowerCase(); if (folderName.matches(".*tests?")) { //$NON-NLS-1$ return true; } } return false; //TODO Maybe check if the folder has java files with a Test or TestSuite suffix? } private Build getOrCreateBuild(Model model) { Build build = model.getBuild(); if (build == null) { build = new Build(); } return build; } /** * Visitor implementation looking for non-Java resources. as soon as such resource is found, a * {@link NonJavaResourceFoundException} is thrown. */ private static class NonJavaResourceVisitor implements IResourceVisitor { //TODO either declare a complete list of extensions or switch to // a different "ignore resource" strategy private static final List<String> IGNORED_EXTENSIONS = Arrays.asList(".svn"); //$NON-NLS-1$ public NonJavaResourceVisitor() { } @SuppressWarnings("unused") public boolean visit(IResource resource) throws CoreException { String resourceName = resource.getProjectRelativePath().lastSegment(); if (resource.isHidden() || isIgnored(resourceName)) { return false; } if (resource instanceof IFile) { IFile file = (IFile) resource; if (!"java".equals(file.getFileExtension())) { throw new NonJavaResourceFoundException(); } } return true; } private boolean isIgnored(String resourceName) { for (String extension : IGNORED_EXTENSIONS) { if (resourceName.endsWith(extension)) { return true; } } return false; } } private static class NonJavaResourceFoundException extends RuntimeException { private static final long serialVersionUID = 1L; public NonJavaResourceFoundException() { } @Override public Throwable fillInStackTrace() { //Overriding fillInStackTrace() reduces the stacktrace creation overhead, //unneeded since this exception is used for flow control. return this; } } private String getCompilerVersion() { //FIXME Workaround until we can get the version from JDT conversion preferences instead //Useful for test purposes. return System.getProperty("org.eclipse.m2e.jdt.conversion.compiler.version", DEFAULT_COMPILER_VERSION); } }