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TraceClassVisitor.javaAPI DocGlassfish v2 API11347Thu Mar 02 11:51:18 GMT 2006oracle.toplink.libraries.asm.util

TraceClassVisitor

public class TraceClassVisitor extends PrintClassVisitor
A {@link PrintClassVisitor PrintClassVisitor} that prints a disassembled view of the classes it visits. This class visitor can be used alone (see the {@link #main main} method) to disassemble a class. It can also be used in the middle of class visitor chain to trace the class that is visited at a given point in this chain. This may be uselful for debugging purposes.

The trace printed when visiting the Hello class is the following: 

// compiled from Hello.java
public class Hello {

public static main ([Ljava/lang/String;)V
GETSTATIC java/lang/System out Ljava/io/PrintStream;
LDC "hello"
INVOKEVIRTUAL java/io/PrintStream println (Ljava/lang/String;)V
RETURN
MAXSTACK = 2
MAXLOCALS = 1

public <init> ()V
ALOAD 0
INVOKESPECIAL java/lang/Object <init> ()V
RETURN
MAXSTACK = 1
MAXLOCALS = 1

}
where Hello is defined by: 

public class Hello {

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

Fields Summary
protected final ClassVisitor
cv
The {@link ClassVisitor ClassVisitor} to which this visitor delegates calls. May be null.
Constructors Summary
public TraceClassVisitor(ClassVisitor cv, PrintWriter pw)
Constructs a new {@link TraceClassVisitor TraceClassVisitor} object.

param
cv the class visitor to which this adapter must delegate calls. May be null.
param
pw the print writer to be used to print the class.

    super(pw);
    this.cv = cv;
Methods Summary
private voidappendAccess(int access)
Appends a string representation of the given access modifiers to {@link #buf buf}.

param
access some access modifiers.

    if ((access & Constants.ACC_PUBLIC) != 0) {
      buf.append("public ");
    }
    if ((access & Constants.ACC_PRIVATE) != 0) {
      buf.append("private ");
    }
    if ((access & Constants.ACC_PROTECTED) != 0) {
      buf.append("protected ");
    }
    if ((access & Constants.ACC_FINAL) != 0) {
      buf.append("final ");
    }
    if ((access & Constants.ACC_STATIC) != 0) {
      buf.append("static ");
    }
    if ((access & Constants.ACC_SYNCHRONIZED) != 0) {
      buf.append("synchronized ");
    }
    if ((access & Constants.ACC_VOLATILE) != 0) {
      buf.append("volatile ");
    }
    if ((access & Constants.ACC_TRANSIENT) != 0) {
      buf.append("transient ");
    }
    // if ((access & Constants.ACC_NATIVE) != 0) {
    //   buf.append("native ");
    // }
    if ((access & Constants.ACC_ABSTRACT) != 0) {
      buf.append("abstract ");
    }
    if ((access & Constants.ACC_STRICT) != 0) {
      buf.append("strictfp ");
    }
public static voidmain(java.lang.String[] args)
Prints a disassembled view of the given class to the standard output.

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

param
args the command line arguments.
throws
Exception if the class cannot be found, or if an IO exception occurs.

    if (args.length < 1 || args.length > 2) {
      printUsage();
    }
    int i = 0;
    boolean skipDebug = true;
    if (args[0].equals("-debug")) {
      i = 1;
      skipDebug = false;
      if (args.length != 2) {
        printUsage();
      }
    }
    ClassReader cr;
    if (args[i].endsWith(".class")) {
      cr = new ClassReader(new FileInputStream(args[i]));
    } else {
      cr = new ClassReader(args[i]);
    }
    cr.accept(new TraceClassVisitor(
      null, new PrintWriter(System.out)), getDefaultAttributes(), skipDebug);
private static voidprintUsage()

    System.err.println("Prints a disassembled view of the given class.");
    System.err.println("Usage: TraceClassVisitor [-debug] " +
                       "<fully qualified class name or class file name>");
    System.exit(-1);
public voidvisit(int version, int access, java.lang.String name, java.lang.String superName, java.lang.String[] interfaces, java.lang.String sourceFile)

    int major = version & 0xFFFF;
    int minor = version >>> 16;
    buf.setLength(0);
    buf.append("// class version " + major + "." + minor + " (" + version + ")\n");
    if ((access & Constants.ACC_DEPRECATED) != 0) {
      buf.append("// DEPRECATED\n");
    }
    if (sourceFile != null) {
      buf.append("// compiled from ").append(sourceFile).append("\n");
    }
    buf.append("// access flags ").append(access).append("\n");
    appendAccess(access & ~Constants.ACC_SUPER);
    if ((access & Constants.ACC_ANNOTATION) != 0) {
      buf.append("@interface ");
    } else if ((access & Constants.ACC_INTERFACE) != 0) {
        buf.append("interface ");
    } else if ((access & Constants.ACC_ENUM) != 0) {
      buf.append("enum ");
    } else {
      buf.append("class ");
    }
    buf.append(name).append(" ");
    if (superName != null && !superName.equals("java/lang/Object")) {
      buf.append("extends ").append(superName).append(" ");
    }
    if (interfaces != null && interfaces.length > 0) {
      buf.append("implements ");
      for (int i = 0; i < interfaces.length; ++i) {
        buf.append(interfaces[i]).append(" ");
      }
    }
    buf.append("{\n\n");
    text.add(buf.toString());

    if (cv != null) {
      cv.visit(version, access, name, superName, interfaces, sourceFile);
    }
public voidvisitAttribute(oracle.toplink.libraries.asm.Attribute attr)

    buf.setLength(0);
    buf.append("  CLASS ATTRIBUTE ").append(attr.type).append(" : ")
      .append(attr.toString()).append("\n");
    text.add(buf.toString());

    if (cv != null) {
      cv.visitAttribute(attr);
    }
public voidvisitEnd()

    text.add("}\n");

    if (cv != null) {
      cv.visitEnd();
    }

    super.visitEnd();
public voidvisitField(int access, java.lang.String name, java.lang.String desc, java.lang.Object value, oracle.toplink.libraries.asm.Attribute attrs)

    buf.setLength(0);
    if ((access & Constants.ACC_DEPRECATED) != 0) {
      buf.append("  // DEPRECATED\n");
    }
    buf.append("  // access flags ").append(access).append("\n");
    buf.append("  ");
    appendAccess(access);
    if ((access & Constants.ACC_ENUM) != 0) {
      buf.append("enum ");
    }
    buf.append(desc)
      .append(" ")
      .append(name);
    if (value != null) {
      buf.append(" = ");
      if (value instanceof String) {
        buf.append("\"").append(value).append("\"");
      } else {
        buf.append(value);
      }
    }
    Attribute attr = attrs;
    while (attr != null) {
      buf.append("  FIELD ATTRIBUTE ").append(attr.type).append(" : ")
        .append(attr.toString()).append("\n");
      attr = attr.next;
    }
    buf.append("\n");
    text.add(buf.toString());

    if (cv != null) {
      cv.visitField(access, name, desc, value, attrs);
    }
public voidvisitInnerClass(java.lang.String name, java.lang.String outerName, java.lang.String innerName, int access)

    buf.setLength(0);
    buf.append("  INNERCLASS ")
      .append(name)
      .append(" ")
      .append(outerName)
      .append(" ")
      .append(innerName)
      .append(" ");
    appendAccess(access & ~Constants.ACC_SUPER);
    if ((access & Constants.ACC_ENUM) != 0) {
      buf.append("enum ");
    }
    buf.append("\n");
    text.add(buf.toString());

    if (cv != null) {
      cv.visitInnerClass(name, outerName, innerName, access);
    }
public oracle.toplink.libraries.asm.CodeVisitorvisitMethod(int access, java.lang.String name, java.lang.String desc, java.lang.String[] exceptions, oracle.toplink.libraries.asm.Attribute attrs)

    buf.setLength(0);
    if ((access & Constants.ACC_DEPRECATED) != 0) {
      buf.append("  // DEPRECATED\n");
    }
    buf.append("  // access flags ").append(access).append("\n");
    buf.append("  ");
    appendAccess(access);
    if ((access & Constants.ACC_NATIVE) != 0) {
      buf.append("native ");
    }
    if ((access & Constants.ACC_VARARGS) != 0) {
      buf.append("varargs ");
    }
    if ((access & Constants.ACC_BRIDGE) != 0) {
      buf.append("bridge ");
    }
    buf.append(name).
      append(" ").
      append(desc);
    if (exceptions != null && exceptions.length > 0) {
      buf.append(" throws ");
      for (int i = 0; i < exceptions.length; ++i) {
        buf.append(exceptions[i]).append(" ");
      }
    }
    buf.append("\n");
    text.add(buf.toString());
    Attribute attr = attrs;
    while (attr != null) {
      buf.setLength(0);
      buf.append("    METHOD ATTRIBUTE ").append(attr.type).append(" : ")
        .append(attr.toString()).append("\n");
      text.add(buf.toString());
      attr = attr.next;
    }

    CodeVisitor cv;
    if (this.cv != null) {
      cv = this.cv.visitMethod(access, name, desc, exceptions, attrs);
    } else {
      cv = null;
    }
    PrintCodeVisitor pcv = new TraceCodeVisitor(cv);
    text.add(pcv.getText());
    return pcv;