asm4/test/conform/org/objectweb/asm/commons/AdviceAdapterUnitTest.java

/***
 * ASM tests
 * Copyright (c) 2000-2011 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
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package org.objectweb.asm.commons;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.objectweb.asm.AbstractTest;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * Simple example of using AdviceAdapter to implement tracing callback
 * 
 * @author Eugene Kuleshov
 */
public class AdviceAdapterUnitTest extends AbstractTest {

    @Override
    public void test() throws Exception {
        Class<?> c = getClass();
        String name = c.getName();
        AdvisingClassLoader cl = new AdvisingClassLoader(name + "$");
        Class<?> cc = cl.loadClass(name + "$B");
        Method m = cc.getMethod("run", new Class<?>[] { Integer.TYPE });
        try {
            m.invoke(null, new Object[] { new Integer(0) });
        } catch (InvocationTargetException e) {
            throw (Exception) e.getTargetException();
        }
    }

    private static class AdvisingClassLoader extends ClassLoader {
        private String prefix;

        public AdvisingClassLoader(final String prefix) throws IOException {
            this.prefix = prefix;
        }

        @Override
        public Class<?> loadClass(final String name)
                throws ClassNotFoundException {
            if (name.startsWith(prefix)) {
                try {
                    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
                    ClassReader cr = new ClassReader(getClass()
                            .getResourceAsStream(
                                    "/" + name.replace('.', '/') + ".class"));
                    cr.accept(new AdviceClassAdapter(cw),
                            ClassReader.EXPAND_FRAMES);
                    byte[] bytecode = cw.toByteArray();
                    return super
                            .defineClass(name, bytecode, 0, bytecode.length);
                } catch (IOException ex) {
                    throw new ClassNotFoundException("Load error: "
                            + ex.toString(), ex);
                }
            }
            return super.loadClass(name);
        }

    }

    // test callback
    private static int n = 0;

    public static void enter(final String msg) {
        System.err.println(off().append("enter ").append(msg).toString());
        n++;
    }

    public static void exit(final String msg) {
        n--;
        System.err.println(off().append("<").toString());
    }

    private static StringBuffer off() {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < n; i++) {
            sb.append("  ");
        }
        return sb;
    }

    static class AdviceClassAdapter extends ClassVisitor implements Opcodes {
        String cname;

        public AdviceClassAdapter(final ClassVisitor cv) {
            super(Opcodes.ASM4, cv);
        }

        @Override
        public void visit(final int version, final int access,
                final String name, final String signature,
                final String superName, final String[] interfaces) {
            this.cname = name;
            super.visit(version, access, name, signature, superName, interfaces);
        }

        @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
                    || (access & (Opcodes.ACC_ABSTRACT | Opcodes.ACC_NATIVE)) > 0) {
                return mv;
            }

            return new AdviceAdapter(Opcodes.ASM4, mv, access, name, desc) {

                @Override
                protected void onMethodEnter() {
                    mv.visitLdcInsn(cname + "." + name + desc);
                    mv.visitMethodInsn(INVOKESTATIC,
                            "org/objectweb/asm/commons/AdviceAdapterUnitTest",
                            "enter", "(Ljava/lang/String;)V");
                }

                @Override
                protected void onMethodExit(final int opcode) {
                    mv.visitLdcInsn(cname + "." + name + desc);
                    mv.visitMethodInsn(INVOKESTATIC,
                            "org/objectweb/asm/commons/AdviceAdapterUnitTest",
                            "exit", "(Ljava/lang/String;)V");
                }

            };
        }
    }

    // TEST CLASSES

    public static class A {
        final String s;

        public A(final String s) {
            this.s = s;
        }

        public A(final A a) {
            this.s = a.s;
        }
    }

    public static class B extends A {

        public B() {
            super(new B(""));
            test(this);
        }

        public B(final A a) {
            super(a);
            test(this);
        }

        public B(final String s) {
            super(s == null ? new A("") : new A(s));
            test(this);
        }

        private static A aa;

        public B(final String s, final A a) {
            this(s == null ? aa = new A(s) : a);
            A aa = new A("");
            test(aa);
        }

        public B(final String s, final String s1) {
            super(s != null ? new A(getA(s1).s) : new A(s));
            test(this);
        }

        private void test(final Object b) {
        }

        private static A getA(final String s) {
            return new A(s);
        }

        // execute all
        public static void run(final int n) {
            new B();
            new B(new A(""));
            new B(new B());
            new B("", new A(""));
            new B("", "");
        }

    }
}