Examples of org.objectweb.asm.util.ASMifierClassVisitor

org.objectweb.asm.util.ASMifierClassVisitor

A {@link PrintClassVisitor PrintClassVisitor} that prints the ASM code thatgenerates 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 {@link ASMifierClassVisitor} visit this compiledclass (see the {@link #main 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.*; 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


    byte[] bytecode = ctx.getGeneratedBytecode();
    
    if (log.isLogging(LoggerLevelStandard.DEBUG)) {
      ClassReader cr = new ClassReader(bytecode);
      ASMifierClassVisitor asm = new ASMifierClassVisitor(
        new PrintWriter(log.getLoggingWriter(LoggerLevelStandard.DEBUG), true) // log.getLoggingWriter(LoggerLevelStandard.INFO), true)
      );
      cr.accept(asm, 0);
    }

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    }
    
    public static Handle createHandle(JRubyClassLoader classLoader, Method method, boolean debug) {
        ClassVisitor cv;
        if (debug) {
            cv = new ASMifierClassVisitor(new PrintWriter(System.out));
        } else {
            cv = new ClassWriter(ClassWriter.COMPUTE_MAXS);
        }


        Class returnType = method.getReturnType();

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  public void testAsmifier() throws Exception {
    URL classUrl = new URL( className);
    byte[] classData = getCode( classUrl.openStream());
    
    StringWriter sw = new StringWriter();
    ASMifierClassVisitor cv = new ASMifierClassVisitor( new PrintWriter( sw));
    
    ClassReader cr = new ClassReader( classData);
    cr.accept(cv, PrintClassVisitor.getDefaultAttributes(), false);


    String name = classUrl.getFile();

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        if (cr.b.length > 20000) {
            return;
        }


        StringWriter sw = new StringWriter();
        ASMifierClassVisitor cv = new ASMifierClassVisitor(new PrintWriter(sw));
        cr.accept(cv, new Attribute[] { new Comment(), new CodeComment() }, 0);


        String generated = sw.toString();


        byte[] generatorClassData;

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Related Classes of org.objectweb.asm.util.ASMifierClassVisitor

net.sourceforge.javautil.bytecode.BytecodeCompiler

org.jruby.compiler.util.HandleFactory

org.objectweb.asm.Attribute

org.objectweb.asm.attrs.AttrsAsmifierTest

org.objectweb.asm.ClassReader

org.objectweb.asm.util.ASMifierTest

java.io.FileInputStream

java.io.PrintWriter

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