org.objectweb.asm.util

Class ASMifierClassVisitor

public class ASMifierClassVisitor extends ASMifierAbstractVisitor implements ClassVisitor

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: 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(0);
         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");
     }
 }
 

Author: Eric Bruneton Eugene Kuleshov

Field Summary
protected PrintWriterpw
The print writer to be used to print the class.
Constructor Summary
ASMifierClassVisitor(PrintWriter pw)
Constructs a new ASMifierClassVisitor object.
Method Summary
protected ASMifierMethodVisitorcreateASMifierMethodVisitor()
static voidmain(String[] args)
Prints the ASM source code to generate the given class to the standard output.
voidvisit(int version, int access, String name, String signature, String superName, String[] interfaces)
AnnotationVisitorvisitAnnotation(String desc, boolean visible)
voidvisitEnd()
FieldVisitorvisitField(int access, String name, String desc, String signature, Object value)
voidvisitInnerClass(String name, String outerName, String innerName, int access)
MethodVisitorvisitMethod(int access, String name, String desc, String signature, String[] exceptions)
voidvisitOuterClass(String owner, String name, String desc)
voidvisitSource(String file, String debug)

Field Detail

pw

protected final PrintWriter pw
The print writer to be used to print the class.

Constructor Detail

ASMifierClassVisitor

public ASMifierClassVisitor(PrintWriter pw)
Constructs a new ASMifierClassVisitor object.

Parameters: pw the print writer to be used to print the class.

Method Detail

createASMifierMethodVisitor

protected ASMifierMethodVisitor createASMifierMethodVisitor()

main

public static void main(String[] args)
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.

Throws: Exception if the class cannot be found, or if an IO exception occurs.

visit

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

visitAnnotation

public AnnotationVisitor visitAnnotation(String desc, boolean visible)

visitEnd

public void visitEnd()

visitField

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

visitInnerClass

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

visitMethod

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

visitOuterClass

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

visitSource

public void visitSource(String file, String debug)