package org.aspectj.apache.bcel.util;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002 The Apache Software Foundation. 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. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache BCEL" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* "Apache BCEL", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.io.OutputStream;
import java.io.PrintWriter;
import org.aspectj.apache.bcel.Constants;
import org.aspectj.apache.bcel.Repository;
import org.aspectj.apache.bcel.classfile.ClassParser;
import org.aspectj.apache.bcel.classfile.ConstantValue;
import org.aspectj.apache.bcel.classfile.Field;
import org.aspectj.apache.bcel.classfile.JavaClass;
import org.aspectj.apache.bcel.classfile.Method;
import org.aspectj.apache.bcel.classfile.Utility;
import org.aspectj.apache.bcel.generic.ArrayType;
import org.aspectj.apache.bcel.generic.ConstantPoolGen;
import org.aspectj.apache.bcel.generic.MethodGen;
import org.aspectj.apache.bcel.generic.Type;
/**
* This class takes a given JavaClass object and converts it to a
* Java program that creates that very class using BCEL. This
* gives new users of BCEL a useful example showing how things
* are done with BCEL. It does not cover all features of BCEL,
* but tries to mimic hand-written code as close as possible.
*
* @version $Id: BCELifier.java,v 1.3 2004/11/22 08:31:27 aclement Exp $
* @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
*/
public class BCELifier extends org.aspectj.apache.bcel.classfile.EmptyVisitor {
private JavaClass _clazz;
private PrintWriter _out;
private ConstantPoolGen _cp;
/** @param clazz Java class to "decompile"
* @param out where to output Java program
*/
public BCELifier(JavaClass clazz, OutputStream out) {
_clazz = clazz;
_out = new PrintWriter(out);
_cp = new ConstantPoolGen(_clazz.getConstantPool());
}
/** Start Java code generation
*/
public void start() {
visitJavaClass(_clazz);
_out.flush();
}
public void visitJavaClass(JavaClass clazz) {
String class_name = clazz.getClassName();
String super_name = clazz.getSuperclassName();
String package_name = clazz.getPackageName();
String inter = Utility.printArray(clazz.getInterfaceNames(),
false, true);
if(!"".equals(package_name)) {
class_name = class_name.substring(package_name.length() + 1);
_out.println("package " + package_name + ";\n");
}
_out.println("import org.aspectj.apache.bcel.generic.*;");
_out.println("import org.aspectj.apache.bcel.classfile.*;");
_out.println("import org.aspectj.apache.bcel.*;");
_out.println("import java.io.*;\n");
_out.println("public class " + class_name + "Creator implements Constants {");
_out.println(" private InstructionFactory _factory;");
_out.println(" private ConstantPoolGen _cp;");
_out.println(" private ClassGen _cg;\n");
_out.println(" public " + class_name + "Creator() {");
_out.println(" _cg = new ClassGen(\"" +
(("".equals(package_name))? class_name :
package_name + "." + class_name) +
"\", \"" + super_name + "\", " +
"\"" + clazz.getSourceFileName() + "\", " +
printFlags(clazz.getAccessFlags(), true) + ", " +
"new String[] { " + inter + " });\n");
_out.println(" _cp = _cg.getConstantPool();");
_out.println(" _factory = new InstructionFactory(_cg, _cp);");
_out.println(" }\n");
printCreate();
Field[] fields = clazz.getFields();
if(fields.length > 0) {
_out.println(" private void createFields() {");
_out.println(" FieldGen field;");
for(int i=0; i < fields.length; i++) {
fields[i].accept(this);
}
_out.println(" }\n");
}
Method[] methods = clazz.getMethods();
for(int i=0; i < methods.length; i++) {
_out.println(" private void createMethod_" + i + "() {");
methods[i].accept(this);
_out.println(" }\n");
}
printMain();
_out.println("}");
}
private void printCreate() {
_out.println(" public void create(OutputStream out) throws IOException {");
Field[] fields = _clazz.getFields();
if(fields.length > 0) {
_out.println(" createFields();");
}
Method[] methods = _clazz.getMethods();
for(int i=0; i < methods.length; i++) {
_out.println(" createMethod_" + i + "();");
}
_out.println(" _cg.getJavaClass().dump(out);");
_out.println(" }\n");
}
private void printMain() {
String class_name = _clazz.getClassName();
_out.println(" public static void main(String[] args) throws Exception {");
_out.println(" " + class_name + "Creator creator = new " +
class_name + "Creator();");
_out.println(" creator.create(new FileOutputStream(\"" + class_name +
".class\"));");
_out.println(" }");
}
public void visitField(Field field) {
_out.println("\n field = new FieldGen(" +
printFlags(field.getAccessFlags()) +
", " + printType(field.getSignature()) + ", \"" +
field.getName() + "\", _cp);");
ConstantValue cv = field.getConstantValue();
if(cv != null) {
String value = cv.toString();
_out.println(" field.setInitValue(" + value + ")");
}
_out.println(" _cg.addField(field.getField());");
}
public void visitMethod(Method method) {
MethodGen mg = new MethodGen(method, _clazz.getClassName(), _cp);
Type result_type = mg.getReturnType();
Type[] arg_types = mg.getArgumentTypes();
_out.println(" InstructionList il = new InstructionList();");
_out.println(" MethodGen method = new MethodGen(" +
printFlags(method.getAccessFlags()) +
", " + printType(result_type) +
", " + printArgumentTypes(arg_types) + ", " +
"new String[] { " +
Utility.printArray(mg.getArgumentNames(), false, true) +
" }, \"" + method.getName() + "\", \"" +
_clazz.getClassName() + "\", il, _cp);\n");
BCELFactory factory = new BCELFactory(mg, _out);
factory.start();
_out.println(" method.setMaxStack();");
_out.println(" method.setMaxLocals();");
_out.println(" _cg.addMethod(method.getMethod());");
_out.println(" il.dispose();");
}
static String printFlags(int flags) {
return printFlags(flags, false);
}
static String printFlags(int flags, boolean for_class) {
if(flags == 0)
return "0";
StringBuffer buf = new StringBuffer();
for(int i=0, pow=1; i <= Constants.MAX_ACC_FLAG; i++) {
if((flags & pow) != 0) {
if((pow == Constants.ACC_SYNCHRONIZED) && for_class)
buf.append("ACC_SUPER | ");
else
buf.append("ACC_" + Constants.ACCESS_NAMES[i].toUpperCase() + " | ");
}
pow <<= 1;
}
String str = buf.toString();
return str.substring(0, str.length() - 3);
}
static String printArgumentTypes(Type[] arg_types) {
if(arg_types.length == 0)
return "Type.NO_ARGS";
StringBuffer args = new StringBuffer();
for(int i=0; i < arg_types.length; i++) {
args.append(printType(arg_types[i]));
if(i < arg_types.length - 1)
args.append(", ");
}
return "new Type[] { " + args.toString() + " }";
}
static String printType(Type type) {
return printType(type.getSignature());
}
static String printType(String signature) {
Type type = Type.getType(signature);
byte t = type.getType();
if(t <= Constants.T_VOID) {
return "Type." + Constants.TYPE_NAMES[t].toUpperCase();
} else if(type.toString().equals("java.lang.String")) {
return "Type.STRING";
} else if(type.toString().equals("java.lang.Object")) {
return "Type.OBJECT";
} else if(type.toString().equals("java.lang.StringBuffer")) {
return "Type.STRINGBUFFER";
} else if(type instanceof ArrayType) {
ArrayType at = (ArrayType)type;
return "new ArrayType(" + printType(at.getBasicType()) +
", " + at.getDimensions() + ")";
} else {
return "new ObjectType(\"" + Utility.signatureToString(signature, false) +
"\")";
}
}
/** Default main method
*/
public static void main(String[] argv) throws Exception {
JavaClass java_class;
String name = argv[0];
if((java_class = Repository.lookupClass(name)) == null)
java_class = new ClassParser(name).parse(); // May throw IOException
BCELifier bcelifier = new BCELifier(java_class, System.out);
bcelifier.start();
}
}