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.commons.jci.classes; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.Label; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; public class ExtendedDump implements Opcodes { public static byte[] dump() throws Exception { ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS); MethodVisitor mv; cw.visit(V1_4, ACC_PUBLIC + ACC_SUPER, "jci/Extended", null, "jci/Simple", null); cw.visitSource("Extended.java", null); { mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null); mv.visitCode(); Label l0 = new Label(); mv.visitLabel(l0); mv.visitLineNumber(3, l0); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, "jci/Simple", "<init>", "()V"); mv.visitInsn(RETURN); Label l1 = new Label(); mv.visitLabel(l1); mv.visitLocalVariable("this", "Ljci/Extended;", null, l0, l1, 0); mv.visitMaxs(1, 1); mv.visitEnd(); } { mv = cw.visitMethod(ACC_PUBLIC, "toString", "()Ljava/lang/String;", null, null); mv.visitCode(); Label l0 = new Label(); mv.visitLabel(l0); mv.visitLineNumber(6, l0); mv.visitTypeInsn(NEW, "java/lang/StringBuffer"); mv.visitInsn(DUP); mv.visitLdcInsn("Extended:"); mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuffer", "<init>", "(Ljava/lang/String;)V"); mv.visitVarInsn(ALOAD, 0); mv.visitMethodInsn(INVOKESPECIAL, "jci/Simple", "toString", "()Ljava/lang/String;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuffer", "append", "(Ljava/lang/String;)Ljava/lang/StringBuffer;"); mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuffer", "toString", "()Ljava/lang/String;"); mv.visitInsn(ARETURN); Label l1 = new Label(); mv.visitLabel(l1); mv.visitLocalVariable("this", "Ljci/Extended;", null, l0, l1, 0); mv.visitMaxs(3, 1); mv.visitEnd(); } cw.visitEnd(); return cw.toByteArray(); } }