org.objectweb.asm.util

Class ASMifierClassVisitor

Implemented Interfaces:
ClassVisitor

public class ASMifierClassVisitor
extends PrintClassVisitor

A PrintClassVisitor that prints the ASM code that generates the classes it visits. This class visitor can be used to quickly write ASM code to generate some given bytecode: The source code printed when visiting the Hello class is the following:

 import org.objectweb.asm.*;
 import java.io.FileOutputStream;

 public class Dump implements Constants {

 public static void main (String[] args) throws Exception {

 ClassWriter cw = new ClassWriter(false);
 CodeVisitor cv;

 cw.visit(ACC_PUBLIC + ACC_SUPER, "Hello", "java/lang/Object", null, "Hello.java");

 {
 cv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC, "main", "([Ljava/lang/String;)V", null, null);
 cv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
 cv.visitLdcInsn("hello");
 cv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V");
 cv.visitInsn(RETURN);
 cv.visitMaxs(2, 1);
 }
 {
 cv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
 cv.visitVarInsn(ALOAD, 0);
 cv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
 cv.visitInsn(RETURN);
 cv.visitMaxs(1, 1);
 }
 cw.visitEnd();

 FileOutputStream os = new FileOutputStream("Dumped.class");
 os.write(cw.toByteArray());
 os.close();
 }
 }
 
where Hello is defined by:

 public class Hello {

   public static void main (String[] args) {
     System.out.println("hello");
   }
 }
 
Author:
Eric Bruneton, Eugene Kuleshov

Field Summary

Fields inherited from class org.objectweb.asm.util.PrintClassVisitor

buf, pw, text

Constructor Summary

ASMifierClassVisitor(PrintWriter pw)
Constructs a new ASMifierClassVisitor object.

Method Summary

static void
main(String[] args)
Prints the ASM source code to generate the given class to the standard output.
void
visit(int version, int access, String name, String superName, String[] interfaces, String sourceFile)
void
visitAttribute(Attribute attr)
void
visitEnd()
void
visitField(int access, String name, String desc, Object value, Attribute attrs)
void
visitInnerClass(String name, String outerName, String innerName, int access)
CodeVisitor
visitMethod(int access, String name, String desc, String[] exceptions, Attribute attrs)

Methods inherited from class org.objectweb.asm.util.PrintClassVisitor

getDefaultAttributes, visitEnd

Constructor Details

ASMifierClassVisitor

public ASMifierClassVisitor(PrintWriter pw)
Parameters:
pw - the print writer to be used to print the class.

Method Details

main

public static void main(String[] args)
            throws Exception
Prints the ASM source code to generate the given class to the standard output.

Usage: ASMifierClassVisitor [-debug] <fully qualified class name or class file name>

Parameters:
args - the command line arguments.

visit

public void visit(int version,
                  int access,
                  String name,
                  String superName,
                  String[] interfaces,
                  String sourceFile)
Specified by:
visit in interface ClassVisitor

visitAttribute

public void visitAttribute(Attribute attr)
Specified by:
visitAttribute in interface ClassVisitor

visitEnd

public void visitEnd()
Specified by:
visitEnd in interface ClassVisitor
Overrides:
visitEnd in interface PrintClassVisitor

visitField

public void visitField(int access,
                       String name,
                       String desc,
                       Object value,
                       Attribute attrs)
Specified by:
visitField in interface ClassVisitor

visitInnerClass

public void visitInnerClass(String name,
                            String outerName,
                            String innerName,
                            int access)
Specified by:
visitInnerClass in interface ClassVisitor

visitMethod

public CodeVisitor visitMethod(int access,
                               String name,
                               String desc,
                               String[] exceptions,
                               Attribute attrs)
Specified by:
visitMethod in interface ClassVisitor