eu.stratosphere.nephele.util.JarFileCreator Maven / Gradle / Ivy
/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.nephele.util;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashSet;
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.
*
* 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> classSet = new HashSet>();
/**
* The final jar file.
*/
private final File outputFile;
/**
* 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 void addClass(final Class clazz) {
this.classSet.add(clazz);
}
/**
* Creates a jar file which contains the previously added class. The content of the jar file is written to
* outputFile which has been provided to the constructor. If outputFile 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 {
// 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> 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));
final InputStream classInputStream = clazz.getResourceAsStream(clazz.getSimpleName() + 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();
}
}