Class ASMifierClassVisitor

A ClassVisitor 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:

• write the Java source code equivalent to the bytecode you want to generate;
• compile it with javac;
• make a ASMifierClassVisitor visit this compiled class (see the main method);
• edit the generated source code, if necessary.

The source code printed when visiting the Hello class is the following:

 import org.objectweb.asm.*;
 
 public class HelloDump implements Opcodes {
 
     public static byte[] dump() throws Exception {
 
         ClassWriter cw = new ClassWriter(false);
         FieldVisitor fv;
         MethodVisitor mv;
         AnnotationVisitor av0;
 
         cw.visit(49,
                 ACC_PUBLIC + ACC_SUPER,
                 "Hello",
                 null,
                 "java/lang/Object",
                 null);
 
         cw.visitSource("Hello.java", null);
 
         {
             mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
             mv.visitVarInsn(ALOAD, 0);
             mv.visitMethodInsn(INVOKESPECIAL,
                     "java/lang/Object",
                     "<init>",
                     "()V");
             mv.visitInsn(RETURN);
             mv.visitMaxs(1, 1);
             mv.visitEnd();
         }
         {
             mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
                     "main",
                     "([Ljava/lang/String;)V",
                     null,
                     null);
             mv.visitFieldInsn(GETSTATIC,
                     "java/lang/System",
                     "out",
                     "Ljava/io/PrintStream;");
             mv.visitLdcInsn("hello");
             mv.visitMethodInsn(INVOKEVIRTUAL,
                     "java/io/PrintStream",
                     "println",
                     "(Ljava/lang/String;)V");
             mv.visitInsn(RETURN);
             mv.visitMaxs(2, 1);
             mv.visitEnd();
         }
         cw.visitEnd();
 
         return cw.toByteArray();
     }
 }
 
 

where Hello is defined by:

 public class Hello {
 
     public static void main(String[] args) {
         System.out.println("hello");
     }
 }
 

protected final PrintWriter pw

public ASMifierClassVisitor(PrintWriter pw)

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

public void visit(int version,
                  int access,
                  String name,
                  String signature,
                  String superName,
                  String[] interfaces)

public AnnotationVisitor visitAnnotation(String desc,
                                         boolean visible)

public void visitEnd()

public FieldVisitor visitField(int access,
                               String name,
                               String desc,
                               String signature,
                               Object value)

public void visitInnerClass(String name,
                            String outerName,
                            String innerName,
                            int access)

public MethodVisitor visitMethod(int access,
                                 String name,
                                 String desc,
                                 String signature,
                                 String[] exceptions)

public void visitOuterClass(String owner,
                            String name,
                            String desc)

public void visitSource(String file,
                        String debug)