jaxp/src/java.xml/share/classes/com/sun/org/apache/bcel/internal/util/BCELifier.java - platform/libcore - Git at Google

 /*
  * reserved comment block
  * DO NOT REMOVE OR ALTER!
  */
 /*
  * 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 com.sun.org.apache.bcel.internal.util;

 import com.sun.org.apache.bcel.internal.classfile.*;
 import com.sun.org.apache.bcel.internal.generic.*;
 import com.sun.org.apache.bcel.internal.Repository;
 import com.sun.org.apache.bcel.internal.Constants;
 import java.io.*;

 /**
  * 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.
  *
  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  */
 public class BCELifier extends com.sun.org.apache.bcel.internal.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 com.sun.org.apache.bcel.internal.generic.*;");
     _out.println("import com.sun.org.apache.bcel.internal.classfile.*;");
     _out.println("import com.sun.org.apache.bcel.internal.*;");
     _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();
   }
 }
	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* 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 com.sun.org.apache.bcel.internal.util;

	import com.sun.org.apache.bcel.internal.classfile.*;
	import com.sun.org.apache.bcel.internal.generic.*;
	import com.sun.org.apache.bcel.internal.Repository;
	import com.sun.org.apache.bcel.internal.Constants;
	import java.io.*;

	/**
	* 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.
	*
	* @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
	*/
	public class BCELifier extends com.sun.org.apache.bcel.internal.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 com.sun.org.apache.bcel.internal.generic.*;");
	_out.println("import com.sun.org.apache.bcel.internal.classfile.*;");
	_out.println("import com.sun.org.apache.bcel.internal.*;");
	_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();
	}
	}