Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.flink.runtime.util; import org.objectweb.asm.ClassReader; import org.objectweb.asm.Opcodes; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashSet; import java.util.List; import java.util.ArrayList; import java.util.Iterator; import java.util.Set; import java.util.jar.JarEntry; import java.util.jar.JarOutputStream; import java.util.jar.Manifest; /** * This is an auxiliary program which creates a jar file from a set of classes. * <p> * This class is thread-safe. * */ public class JarFileCreator { /** * The file extension of java classes. */ private static final String CLASS_EXTENSION = ".class"; /** * A set of classes which shall be included in the final jar file. */ private final Set<Class<?>> classSet = new HashSet<Class<?>>(); /** * The final jar file. */ private final File outputFile; /** * The namespace of the dependencies to be packaged. */ private final Set<String> packages = new HashSet<String>(); /** * Constructs a new jar file creator. * * @param outputFile * the file which shall contain the output data, i.e. the final jar file */ public JarFileCreator(final File outputFile) { this.outputFile = outputFile; } /** * Adds a {@link Class} object to the set of classes which shall eventually be included in the jar file. * * @param clazz * the class to be added to the jar file. */ public synchronized JarFileCreator addClass(final Class<?> clazz) { this.classSet.add(clazz); String name = clazz.getName(); int n = name.lastIndexOf('.'); if (n > -1) { name = name.substring(0, n); } return addPackage(name); } /** * Manually specify the package of the dependencies. * * @param p * the package to be included. */ public synchronized JarFileCreator addPackage(String p) { this.packages.add(p); return this; } /** * Manually specify the packages of the dependencies. * * @param packages * the packages to be included. */ public synchronized JarFileCreator addPackages(String[] packages) { for (String p : packages) { addPackage(p); } return this; } /** * Add the dependencies within the given packages automatically. * @throws IOException * throw if an error occurs while read the class file. */ private synchronized void addDependencies() throws IOException { List<String> dependencies = new ArrayList<String>(); for (Class clazz : classSet) { dependencies.add(clazz.getName()); } //Traverse the dependency tree using BFS. int head = 0; while (head != dependencies.size()) { DependencyVisitor v = new DependencyVisitor(Opcodes.ASM5); v.addNameSpace(this.packages); InputStream classInputStream = null; String name = dependencies.get(head); try { Class clazz = Class.forName(name); int n = name.lastIndexOf('.'); String className = null; if (n > -1) { className = name.substring(n + 1, name.length()); } classInputStream = clazz.getResourceAsStream(className + CLASS_EXTENSION); } catch (ClassNotFoundException e) { throw new RuntimeException(e.getMessage()); } new ClassReader(classInputStream).accept(v, 0); classInputStream.close(); //Update the BFS queue. Set<String> classPackages = v.getPackages(); for (String s : classPackages) { if (!dependencies.contains(s.replace('/', '.'))) { dependencies.add(s.replace('/', '.')); } } head++; } for (String dependency : dependencies) { try { this.classSet.add(Class.forName(dependency)); } catch (ClassNotFoundException e) { throw new RuntimeException(e.getMessage()); } } } /** * Creates a jar file which contains the previously added class. The content of the jar file is written to * <code>outputFile</code> which has been provided to the constructor. If <code>outputFile</code> already exists, it * is overwritten by this operation. * * @throws IOException * thrown if an error occurs while writing to the output file */ public synchronized void createJarFile() throws IOException { //Retrieve dependencies automatically addDependencies(); // Temporary buffer for the stream copy final byte[] buf = new byte[128]; // Check if output file is valid if (this.outputFile == null) { throw new IOException("Output file is null"); } // If output file already exists, delete it if (this.outputFile.exists()) { this.outputFile.delete(); } final JarOutputStream jos = new JarOutputStream(new FileOutputStream(this.outputFile), new Manifest()); final Iterator<Class<?>> it = this.classSet.iterator(); while (it.hasNext()) { final Class<?> clazz = it.next(); final String entry = clazz.getName().replace('.', '/') + CLASS_EXTENSION; jos.putNextEntry(new JarEntry(entry)); String name = clazz.getName(); int n = name.lastIndexOf('.'); String className = null; if (n > -1) { className = name.substring(n + 1, name.length()); } //Using the part after last dot instead of class.getSimpleName() could resolve the problem of inner class. final InputStream classInputStream = clazz.getResourceAsStream(className + CLASS_EXTENSION); int num = classInputStream.read(buf); while (num != -1) { jos.write(buf, 0, num); num = classInputStream.read(buf); } classInputStream.close(); jos.closeEntry(); } jos.close(); } }