/***
* ASM examples: examples showing how ASM can be used
* Copyright (c) 2000-2007 INRIA, France Telecom
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
import org.ow2.asm.Attribute;
import org.ow2.asm.FieldVisitor;
import org.ow2.asm.ClassAdapter;
import org.ow2.asm.ClassReader;
import org.ow2.asm.ClassVisitor;
import org.ow2.asm.ClassWriter;
import org.ow2.asm.MethodVisitor;
import org.ow2.asm.Opcodes;
import org.ow2.asm.Label;
import org.ow2.asm.ByteVector;
import org.ow2.asm.util.TraceClassVisitor;
import java.io.FileOutputStream;
import java.io.PrintWriter;
/**
* @author Eric Bruneton
*/
public class Attributes extends ClassLoader {
public static void main(final String args[]) throws Exception {
// loads the original class and adapts it
ClassReader cr = new ClassReader("CommentAttribute");
ClassWriter cw = new ClassWriter(0);
ClassVisitor cv = new AddCommentClassAdapter(cw);
cr.accept(cv, new Attribute[] { new CommentAttribute("") }, 0);
byte[] b = cw.toByteArray();
// stores the adapted class on disk
FileOutputStream fos = new FileOutputStream("CommentAttribute.class.new");
try {
fos.write(b);
} finally {
fos.close();
}
// "disassembles" the adapted class
cr = new ClassReader(b);
cv = new TraceClassVisitor(new PrintWriter(System.out));
cr.accept(cv, new Attribute[] { new CommentAttribute("") }, 0);
}
}
class AddCommentClassAdapter extends ClassAdapter implements Opcodes {
public AddCommentClassAdapter(final ClassVisitor cv) {
super(cv);
}
@Override
public void visit(
final int version,
final int access,
final String name,
final String signature,
final String superName,
final String[] interfaces)
{
super.visit(version, access, name, signature, superName, interfaces);
visitAttribute(new CommentAttribute("this is a class comment"));
}
@Override
public FieldVisitor visitField(
final int access,
final String name,
final String desc,
final String signature,
final Object value)
{
FieldVisitor fv = super.visitField(access, name, desc, signature, value);
fv.visitAttribute(new CommentAttribute("this is a field comment"));
return fv;
}
@Override
public MethodVisitor visitMethod(
final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions)
{
MethodVisitor mv = cv.visitMethod(access,
name,
desc,
signature,
exceptions);
if (mv != null) {
mv.visitAttribute(new CommentAttribute("this is a method comment"));
}
return mv;
}
}
class CommentAttribute extends Attribute {
private String comment;
public CommentAttribute(final String comment) {
super("Comment");
this.comment = comment;
}
public String getComment() {
return comment;
}
@Override
public boolean isUnknown() {
return false;
}
@Override
protected Attribute read(
final ClassReader cr,
final int off,
final int len,
final char[] buf,
final int codeOff,
final Label[] labels)
{
return new CommentAttribute(cr.readUTF8(off, buf));
}
@Override
protected ByteVector write(
final ClassWriter cw,
final byte[] code,
final int len,
final int maxStack,
final int maxLocals)
{
return new ByteVector().putShort(cw.newUTF8(comment));
}
}