org.mvel2.asm.util

Class TraceClassVisitor

java.lang.Object

org.mvel2.asm.ClassVisitor

org.mvel2.asm.util.TraceClassVisitor

public final class TraceClassVisitor
extends ClassVisitor

A ClassVisitor that prints the classes it visits with a Printer. This class visitor can be used in the middle of a class visitor chain to trace the class that is visited at a given point in this chain. This may be useful for debugging purposes.

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

 // class version 49.0 (49) // access flags 0x21 public class Hello {
 
 // compiled from: Hello.java
 
 // access flags 0x1 public <init> ()V ALOAD 0 INVOKESPECIAL
 java/lang/Object <init> ()V RETURN MAXSTACK = 1 MAXLOCALS = 1
 
 // access flags 0x9 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 }
 

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

Modifier and Type	Field and Description
Printer	p The object that actually converts visit events into text.

Fields inherited from class org.mvel2.asm.ClassVisitor

api, cv

Constructor Summary

Constructors

Constructor and Description
TraceClassVisitor(ClassVisitor cv, Printer p, PrintWriter pw) Constructs a new TraceClassVisitor.
TraceClassVisitor(ClassVisitor cv, PrintWriter pw) Constructs a new TraceClassVisitor.
TraceClassVisitor(PrintWriter pw) Constructs a new TraceClassVisitor.

Method Summary

Methods

Modifier and Type	Method and Description
void	visit(int version, int access, String name, String signature, String superName, String[] interfaces) Visits the header of the class.
AnnotationVisitor	visitAnnotation(String desc, boolean visible) Visits an annotation of the class.
void	visitAttribute(Attribute attr) Visits a non standard attribute of the class.
void	visitEnd() Visits the end of the class.
FieldVisitor	visitField(int access, String name, String desc, String signature, Object value) Visits a field of the class.
void	visitInnerClass(String name, String outerName, String innerName, int access) Visits information about an inner class.
MethodVisitor	visitMethod(int access, String name, String desc, String signature, String[] exceptions) Visits a method of the class.
void	visitOuterClass(String owner, String name, String desc) Visits the enclosing class of the class.
void	visitSource(String file, String debug) Visits the source of the class.
AnnotationVisitor	visitTypeAnnotation(int typeRef, TypePath typePath, String desc, boolean visible) Visits an annotation on a type in the class signature.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

p

public final Printer p

The object that actually converts visit events into text.

Constructor Detail

TraceClassVisitor

public TraceClassVisitor(PrintWriter pw)

Constructs a new TraceClassVisitor.

Parameters:

pw - the print writer to be used to print the class.

TraceClassVisitor

public TraceClassVisitor(ClassVisitor cv,
                 PrintWriter pw)

Constructs a new TraceClassVisitor.

Parameters:

cv - the ClassVisitor to which this visitor delegates calls. May be null.

pw - the print writer to be used to print the class.

TraceClassVisitor

public TraceClassVisitor(ClassVisitor cv,
                 Printer p,
                 PrintWriter pw)

Constructs a new TraceClassVisitor.

Parameters:

cv - the ClassVisitor to which this visitor delegates calls. May be null.

p - the object that actually converts visit events into text.

pw - the print writer to be used to print the class. May be null if you simply want to use the result via Printer.getText(), instead of printing it.

Method Detail

visit

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

Description copied from class: ClassVisitor

Visits the header of the class.

Overrides:

visit in class ClassVisitor

Parameters:

version - the class version.

access - the class's access flags (see Opcodes). This parameter also indicates if the class is deprecated.

name - the internal name of the class (see getInternalName).

signature - the signature of this class. May be null if the class is not a generic one, and does not extend or implement generic classes or interfaces.

superName - the internal of name of the super class (see getInternalName). For interfaces, the super class is Object. May be null, but only for the Object class.

interfaces - the internal names of the class's interfaces (see getInternalName). May be null.

visitSource

public void visitSource(String file,
               String debug)

Description copied from class: ClassVisitor

Visits the source of the class.

Overrides:

visitSource in class ClassVisitor

Parameters:

file - the name of the source file from which the class was compiled. May be null.

debug - additional debug information to compute the correspondance between source and compiled elements of the class. May be null.

visitOuterClass

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

Description copied from class: ClassVisitor

Visits the enclosing class of the class. This method must be called only if the class has an enclosing class.

Overrides:

visitOuterClass in class ClassVisitor

Parameters:

owner - internal name of the enclosing class of the class.

name - the name of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.

desc - the descriptor of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.

visitAnnotation

public AnnotationVisitor visitAnnotation(String desc,
                                boolean visible)

Description copied from class: ClassVisitor

Visits an annotation of the class.

Overrides:

visitAnnotation in class ClassVisitor

Parameters:

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitTypeAnnotation

public AnnotationVisitor visitTypeAnnotation(int typeRef,
                                    TypePath typePath,
                                    String desc,
                                    boolean visible)

Description copied from class: ClassVisitor

Visits an annotation on a type in the class signature.

Overrides:

visitTypeAnnotation in class ClassVisitor

Parameters:

typeRef - a reference to the annotated type. The sort of this type reference must be CLASS_TYPE_PARAMETER, CLASS_TYPE_PARAMETER_BOUND or CLASS_EXTENDS. See TypeReference.

typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.

desc - the class descriptor of the annotation class.

visible - true if the annotation is visible at runtime.

Returns:

a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitAttribute

public void visitAttribute(Attribute attr)

Description copied from class: ClassVisitor

Visits a non standard attribute of the class.

Overrides:

visitAttribute in class ClassVisitor

Parameters:

attr - an attribute.

visitInnerClass

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

Description copied from class: ClassVisitor

Visits information about an inner class. This inner class is not necessarily a member of the class being visited.

Overrides:

visitInnerClass in class ClassVisitor

Parameters:

name - the internal name of an inner class (see getInternalName).

outerName - the internal name of the class to which the inner class belongs (see getInternalName). May be null for not member classes.

innerName - the (simple) name of the inner class inside its enclosing class. May be null for anonymous inner classes.

access - the access flags of the inner class as originally declared in the enclosing class.

visitField

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

Description copied from class: ClassVisitor

Visits a field of the class.

Overrides:

visitField in class ClassVisitor

Parameters:

access - the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.

name - the field's name.

desc - the field's descriptor (see Type).

signature - the field's signature. May be null if the field's type does not use generic types.

value - the field's initial value. This parameter, which may be null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String (for int, float, long or String fields respectively). This parameter is only used for static fields. Its value is ignored for non static fields, which must be initialized through bytecode instructions in constructors or methods.

Returns:

a visitor to visit field annotations and attributes, or null if this class visitor is not interested in visiting these annotations and attributes.

visitMethod

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

Description copied from class: ClassVisitor

Visits a method of the class. This method must return a new MethodVisitor instance (or null) each time it is called, i.e., it should not return a previously returned visitor.

Overrides:

visitMethod in class ClassVisitor

Parameters:

access - the method's access flags (see Opcodes). This parameter also indicates if the method is synthetic and/or deprecated.

name - the method's name.

desc - the method's descriptor (see Type).

signature - the method's signature. May be null if the method parameters, return type and exceptions do not use generic types.

exceptions - the internal names of the method's exception classes (see getInternalName). May be null.

Returns:

an object to visit the byte code of the method, or null if this class visitor is not interested in visiting the code of this method.

visitEnd

public void visitEnd()

Description copied from class: ClassVisitor

Visits the end of the class. This method, which is the last one to be called, is used to inform the visitor that all the fields and methods of the class have been visited.

Overrides:

visitEnd in class ClassVisitor