javassist.tools.reflect

Class Reflection

java.lang.Object

javassist.tools.reflect.Reflection

All Implemented Interfaces:

Translator

public class Reflection
extends Object
implements Translator

The class implementing the behavioral reflection mechanism.

If a class is reflective, then all the method invocations on every instance of that class are intercepted by the runtime metaobject controlling that instance. The methods inherited from the super classes are also intercepted except final methods. To intercept a final method in a super class, that super class must be also reflective.

To do this, the original class file representing a reflective class:

 class Person {
   public int f(int i) { return i + 1; }
   public int value;
 }
 

is modified so that it represents a class:

 class Person implements Metalevel {
   public int _original_f(int i) { return i + 1; }
   public int f(int i) { delegate to the metaobject }

   public int value;
   public int _r_value() { read "value" }
   public void _w_value(int v) { write "value" }

   public ClassMetaobject _getClass() { return a class metaobject }
   public Metaobject _getMetaobject() { return a metaobject }
   public void _setMetaobject(Metaobject m) { change a metaobject }
 }
 

See Also:

ClassMetaobject, Metaobject, Loader, Compiler

Field Summary

Fields

Modifier and Type	Field and Description
protected ClassPool	classPool
protected CodeConverter	converter
protected CtClass[]	readParam
protected CtMethod	trapMethod
protected CtMethod	trapRead
protected CtMethod	trapStaticMethod
protected CtMethod	trapWrite

Constructor Summary

Constructors

Constructor and Description
Reflection() Constructs a new Reflection object.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	makeReflective(Class clazz, Class metaobject, Class metaclass) Produces a reflective class.
boolean	makeReflective(CtClass clazz, CtClass metaobject, CtClass metaclass) Produces a reflective class.
boolean	makeReflective(String classname, String metaobject, String metaclass) Produces a reflective class.
void	onLoad(ClassPool pool, String classname) Inserts hooks for intercepting accesses to the fields declared in reflective classes.
void	rebuildClassFile(ClassFile cf)
void	start(ClassPool pool) Initializes the object.

Methods inherited from class java.lang.Object

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

Field Detail

trapMethod

protected CtMethod trapMethod

trapStaticMethod

protected CtMethod trapStaticMethod

trapRead

protected CtMethod trapRead

trapWrite

protected CtMethod trapWrite

readParam

protected CtClass[] readParam

classPool

protected ClassPool classPool

converter

protected CodeConverter converter

Constructor Detail

Reflection

public Reflection()

Constructs a new Reflection object.

Method Detail

start

public void start(ClassPool pool)
           throws NotFoundException

Initializes the object.

Specified by:

start in interface Translator

Parameters:

pool - the ClassPool that this translator should use.

Throws:

NotFoundException - if a CtClass cannot be found.

See Also:

Loader

onLoad

public void onLoad(ClassPool pool,
          String classname)
            throws CannotCompileException,
                   NotFoundException

Inserts hooks for intercepting accesses to the fields declared in reflective classes.

Specified by:

onLoad in interface Translator

Parameters:

pool - the ClassPool that this translator should use.

classname - the name of the class being loaded.

Throws:

CannotCompileException - if the code transformation by this method fails.

NotFoundException - if a CtClass cannot be found.

See Also:

Loader

makeReflective

public boolean makeReflective(String classname,
                     String metaobject,
                     String metaclass)
                       throws CannotCompileException,
                              NotFoundException

Produces a reflective class. If the super class is also made reflective, it must be done before the sub class.

Parameters:

classname - the name of the reflective class

metaobject - the class name of metaobjects.

metaclass - the class name of the class metaobject.

Returns:

false if the class is already reflective.

Throws:

CannotCompileException

NotFoundException

See Also:

Metaobject, ClassMetaobject

makeReflective

public boolean makeReflective(Class clazz,
                     Class metaobject,
                     Class metaclass)
                       throws CannotCompileException,
                              NotFoundException

Produces a reflective class. If the super class is also made reflective, it must be done before the sub class.

Parameters:

clazz - the reflective class.

metaobject - the class of metaobjects. It must be a subclass of Metaobject.

metaclass - the class of the class metaobject. It must be a subclass of ClassMetaobject.

Returns:

false if the class is already reflective.

Throws:

CannotCompileException

NotFoundException

See Also:

Metaobject, ClassMetaobject

makeReflective

public boolean makeReflective(CtClass clazz,
                     CtClass metaobject,
                     CtClass metaclass)
                       throws CannotCompileException,
                              CannotReflectException,
                              NotFoundException

Produces a reflective class. It modifies the given CtClass object and makes it reflective. If the super class is also made reflective, it must be done before the sub class.

Parameters:

clazz - the reflective class.

metaobject - the class of metaobjects. It must be a subclass of Metaobject.

metaclass - the class of the class metaobject. It must be a subclass of ClassMetaobject.

Returns:

false if the class is already reflective.

Throws:

CannotCompileException

CannotReflectException

NotFoundException

See Also:

Metaobject, ClassMetaobject

rebuildClassFile

public void rebuildClassFile(ClassFile cf)
                      throws BadBytecode

Throws:

BadBytecode