org.objectweb.asm.util
Class TraceClassVisitor
- ClassVisitor
public class TraceClassVisitor
A
ClassVisitor
that prints a disassembled view of the classes it
visits. This class visitor can be used alone (see the
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:
// class version 49.0 (49)
// access flags 33
public class Hello {
// compiled from: Hello.java
// access flags 1
public <init> ()V
ALOAD 0
INVOKESPECIAL java/lang/Object <init> ()V
RETURN
MAXSTACK = 1
MAXLOCALS = 1
// access flags 9
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");
}
}
- Eric Bruneton
- Eugene Kuleshov
protected ClassVisitor | cv - The
ClassVisitor to which this visitor delegates calls.
|
protected PrintWriter | pw - The print writer to be used to print the class.
|
protected TraceFieldVisitor | createTraceFieldVisitor()
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protected TraceMethodVisitor | createTraceMethodVisitor()
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static void | main(String[] args) - Prints a disassembled view of the given class to the standard output.
|
void | visit(int version, int access, String name, String signature, String superName, String[] interfaces) - Visits the header of the class.
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AnnotationVisitor | visitAnnotation(String desc, boolean visible) - Visits an annotation of the class.
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void | visitAttribute(Attribute attr) - Visits a non standard attribute of the class.
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void | visitEnd() - Visits the end of the class.
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FieldVisitor | visitField(int access, String name, String desc, String signature, Object value) - Visits a field of the class.
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void | visitInnerClass(String name, String outerName, String innerName, int access) - Visits information about an inner class.
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MethodVisitor | visitMethod(int access, String name, String desc, String signature, String[] exceptions) - Visits a method of the class.
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void | visitOuterClass(String owner, String name, String desc) - Visits the enclosing class of the class.
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void | visitSource(String file, String debug) - Visits the source of the class.
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pw
protected final PrintWriter pw
The print writer to be used to print the class.
TraceClassVisitor
public TraceClassVisitor(PrintWriter pw)
pw
- the print writer to be used to print the class.
TraceClassVisitor
public TraceClassVisitor(ClassVisitor cv,
PrintWriter pw)
cv
- the ClassVisitor
to which this visitor delegates calls.
May be null.pw
- the print writer to be used to print the class.
main
public static void main(String[] args)
throws Exception
Prints a disassembled view of the given class to the standard output.
Usage: TraceClassVisitor [-debug] <fully qualified class name or class
file name >
args
- the command line arguments.
visit
public void visit(int version,
int access,
String name,
String signature,
String superName,
String[] interfaces)
Visits the header of the class.
- visit in interface ClassVisitor
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.
visitAnnotation
public AnnotationVisitor visitAnnotation(String desc,
boolean visible)
Visits an annotation of the class.
- visitAnnotation in interface ClassVisitor
- visitAnnotation in interface TraceAbstractVisitor
desc
- the class descriptor of the annotation class.visible
- true if the annotation is visible at runtime.
- a visitor to visit the annotation values, or null if
this visitor is not interested in visiting this annotation.
visitEnd
public void visitEnd()
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.
- visitEnd in interface ClassVisitor
- visitEnd in interface TraceAbstractVisitor
visitField
public FieldVisitor visitField(int access,
String name,
String desc,
String signature,
Object value)
Visits a field of the class.
- visitField in interface ClassVisitor
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.
- a visitor to visit field annotations and attributes, or
null if this class visitor is not interested in
visiting these annotations and attributes.
visitInnerClass
public void visitInnerClass(String name,
String outerName,
String innerName,
int access)
Visits information about an inner class. This inner class is not
necessarily a member of the class being visited.
- visitInnerClass in interface ClassVisitor
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.
visitMethod
public MethodVisitor visitMethod(int access,
String name,
String desc,
String signature,
String[] exceptions)
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.
- visitMethod in interface ClassVisitor
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.
- 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.
visitOuterClass
public void visitOuterClass(String owner,
String name,
String desc)
Visits the enclosing class of the class. This method must be called only
if the class has an enclosing class.
- visitOuterClass in interface ClassVisitor
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.
visitSource
public void visitSource(String file,
String debug)
Visits the source of the class.
- visitSource in interface ClassVisitor
debug
- additional debug information to compute the correspondance
between source and compiled elements of the class. May be
null.