Java tutorial
/* * Copyright 2010-2012 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.cloudfoundry.tools.compiler; import java.io.File; import java.io.InputStream; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.Writer; import java.nio.charset.Charset; import java.util.ArrayList; import java.util.Collections; import java.util.EnumSet; import java.util.Iterator; import java.util.List; import java.util.Locale; import java.util.Set; import javax.annotation.processing.Processor; import javax.lang.model.SourceVersion; import javax.tools.DiagnosticListener; import javax.tools.JavaCompiler; import javax.tools.JavaFileManager; import javax.tools.JavaFileObject; import javax.tools.StandardJavaFileManager; import javax.tools.StandardLocation; import org.eclipse.jdt.internal.compiler.batch.Main; import org.eclipse.jdt.internal.compiler.impl.CompilerOptions; import org.eclipse.jdt.internal.compiler.tool.EclipseBatchCompiler; import org.eclipse.jdt.internal.compiler.tool.EclipseFileManager; import org.eclipse.jdt.internal.compiler.tool.Options; import org.springframework.util.Assert; import org.springframework.util.StringUtils; /** * {@link JavaCompiler} implementation compatible with cloud foundry. * * @author Phillip Webb */ public class CloudFoundryJavaCompiler implements JavaCompiler { private static final Set<SourceVersion> SOURCE_VERSIONS; static { SOURCE_VERSIONS = Collections .unmodifiableSet(EnumSet.range(SourceVersion.RELEASE_0, SourceVersion.RELEASE_6)); } @Override public Set<SourceVersion> getSourceVersions() { return SOURCE_VERSIONS; } @Override public StandardJavaFileManager getStandardFileManager( DiagnosticListener<? super JavaFileObject> diagnosticListener, Locale locale, Charset charset) { return new EclipseFileManager(locale, charset); } @Override @SuppressWarnings("unchecked") public CompilationTask getTask(Writer out, JavaFileManager fileManager, DiagnosticListener<? super JavaFileObject> diagnosticListener, Iterable<String> options, Iterable<String> classes, Iterable<? extends JavaFileObject> compilationUnits) { if (fileManager == null) { fileManager = this.getStandardFileManager(diagnosticListener, null, null); } PrintWriter writer = createPrintWriter(out); EclipseBatchCompiler batchCompiler = new EclipseBatchCompiler(writer, writer, false); batchCompiler.options.put(CompilerOptions.OPTION_Compliance, CompilerOptions.VERSION_1_6); batchCompiler.options.put(CompilerOptions.OPTION_Source, CompilerOptions.VERSION_1_6); batchCompiler.options.put(CompilerOptions.OPTION_TargetPlatform, CompilerOptions.VERSION_1_6); batchCompiler.diagnosticListener = diagnosticListener; batchCompiler.fileManager = fileManager; batchCompiler.setCompilationUnits(compilationUnits); if (options != null) { for (Iterator<String> iterator = options.iterator(); iterator.hasNext();) { batchCompiler.fileManager.handleOption(iterator.next(), iterator); } } batchCompiler.configure(getArgumentsForBatchCompiler(asList(options), asList(classes))); if (fileManager instanceof StandardJavaFileManager) { Iterable<? extends File> location = ((StandardJavaFileManager) fileManager) .getLocation(StandardLocation.CLASS_OUTPUT); if (location != null) { batchCompiler.setDestinationPath(location.iterator().next().getAbsolutePath()); } } return new CompilationTaskImpl(batchCompiler); } /** * Adapt any tasks options for use with the eclipse batch compiler. * * @param options the source options (never null) * @param classes the class (never null) * @return a set of options that can be applied to the {@link EclipseBatchCompiler} */ private String[] getArgumentsForBatchCompiler(List<String> options, List<String> classes) { ArrayList<String> arguments = new ArrayList<String>(); arguments.addAll(options); if (!classes.isEmpty()) { arguments.add("-classNames"); arguments.add(StringUtils.collectionToCommaDelimitedString(classes)); } return arguments.toArray(new String[arguments.size()]); } @Override public int isSupportedOption(String option) { return Options.processOptions(option); } @Override public int run(InputStream in, OutputStream out, OutputStream err, String... arguments) { Main compiler = new Main(createPrintWriter(out), createPrintWriter(err), true, null, null); boolean succeed = compiler.compile(arguments); return succeed ? 0 : -1; } /** * Create a new {@link PrintWriter} for the specified output stream. * * @param outputStream the output stream * @return a print writer */ private PrintWriter createPrintWriter(OutputStream outputStream) { Assert.notNull(outputStream, "OutputStream must not be null"); return createPrintWriter(new OutputStreamWriter(outputStream)); } /** * Create a new {@link PrintWriter} for the specified (optional) writer. If the writer is not specified * {@link System#err} will be used. * * @param writer a writer or <tt>null</tt> * @return a print writer */ private PrintWriter createPrintWriter(Writer writer) { if (writer != null) { return new PrintWriter(writer); } return new PrintWriter(System.err); } /** * Adapt an iterable to a list. If the iterable is <tt>null</tt> an empty list is returned. * * @param iterable the iterable to convert * @return a list containing all items from the iterable */ private static <T> List<T> asList(Iterable<T> iterable) { if (iterable == null) { return Collections.emptyList(); } List<T> list = new ArrayList<T>(); for (T item : iterable) { list.add(item); } return list; } /** * The compilation task implementation. */ private static class CompilationTaskImpl implements CompilationTask { private final EclipseBatchCompiler compiler; private boolean called = false; public CompilationTaskImpl(EclipseBatchCompiler compiler) { this.compiler = compiler; } @Override public void setLocale(Locale locale) { this.compiler.setLocale(locale); } @Override public void setProcessors(Iterable<? extends Processor> processors) { List<? extends Processor> processorsList = asList(processors); Processor[] processorsArray = processorsList.toArray(new Processor[processorsList.size()]); this.compiler.setProcessors(processorsArray); } @Override public Boolean call() { try { Assert.state(!this.called, "The compilation task has already been called"); return this.compiler.call(); } finally { this.called = true; } } } }