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/*
* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package compiler.jsr292.methodHandleExceptions;
import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
/**
* A ByteClassLoader is used to define classes from collections of bytes, as
* well as loading classes in the usual way. It includes options to write the
* classes to files in a jar, or to read the classes from jars in a later or
* debugging run.
*
* If Boolean property byteclassloader.verbose is true, be chatty about jar
* file operations.
*
*/
public class ByteClassLoader extends URLClassLoader {
final static boolean verbose
= Boolean.getBoolean("byteclassloader.verbose");
final boolean read;
final JarOutputStream jos;
final String jar_name;
/**
* Make a new ByteClassLoader.
*
* @param jar_name Basename of jar file to be read/written by this classloader.
* @param read If true, read classes from jar file instead of from parameter.
* @param write If true, write classes to jar files for offline study/use.
*
* @throws FileNotFoundException
* @throws IOException
*/
public ByteClassLoader(String jar_name, boolean read, boolean write)
throws FileNotFoundException, IOException {
super(read
? new URL[]{new URL("file:" + jar_name + ".jar")}
: new URL[0]);
this.read = read;
this.jar_name = jar_name;
this.jos = write
? new JarOutputStream(
new BufferedOutputStream(
new FileOutputStream(jar_name + ".jar"))) : null;
if (read && write) {
throw new Error("At most one of read and write may be true.");
}
}
private static void writeJarredFile(JarOutputStream jos, String file, String suffix, byte[] bytes) {
String fileName = file.replace(".", "/") + "." + suffix;
JarEntry ze = new JarEntry(fileName);
try {
ze.setSize(bytes.length);
jos.putNextEntry(ze);
jos.write(bytes);
jos.closeEntry();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* (pre)load class name using classData for the definition.
*
* @param name
* @param classData
* @return
*/
public Class<?> loadBytes(String name, byte[] classData) throws ClassNotFoundException {
if (jos != null) {
if (verbose) {
System.out.println("ByteClassLoader: writing " + name);
}
writeJarredFile(jos, name, "class", classData);
}
Class<?> clazz = null;
if (read) {
if (verbose) {
System.out.println("ByteClassLoader: reading " + name + " from " + jar_name);
}
clazz = loadClass(name);
} else {
clazz = defineClass(name, classData, 0, classData.length);
resolveClass(clazz);
}
return clazz;
}
public void close() {
if (jos != null) {
try {
if (verbose) {
System.out.println("ByteClassLoader: closing " + jar_name);
}
jos.close();
} catch (IOException ex) {
}
}
}
}
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