com.github.randomcodeorg.ppplugin.ppdefaults

Class ByteCodeHelper

java.lang.Object

com.github.randomcodeorg.ppplugin.ppdefaults.ByteCodeHelper

public class ByteCodeHelper
extends java.lang.Object

A helper class to simplify the modification of generated class files. Please see the documentation of the edit(CtClass, Class) method.

Author:

Marcel Singer

Constructor Summary

Constructors

Constructor and Description
ByteCodeHelper(com.github.randomcodeorg.ppplugin.PContext context) Creates a new ByteCodeHelper using the given context.

Method Summary

Modifier and Type	Method and Description
void	commit() The same as ByteCodeHelper#commit(true).
void	commit(boolean continueOnException) Compiles the changes and applies them to the corresponding .class-files.
boolean	edit(javassist.CtClass cl, java.lang.Class<?> runtimeClass) Marks the given class as edited.
static javassist.CtMethod	findMethod(javassist.CtClass clazz, java.lang.reflect.Method m) Finds the Method corresponding to the given javassist CtMethod.
javassist.ClassPool	getClassPool() Returns the javassist ClassPool used by this instance.
javassist.CtField	getOrCreateField(javassist.CtClass ctClass, java.lang.String typeName, java.lang.String fieldPrefix, java.lang.String visibility, boolean isStatic, boolean isFinal, java.lang.String initValue) Returns a existing field or creates one.
void	releaseResources() Releases the resources of created by this instance.

Methods inherited from class java.lang.Object

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

Constructor Detail

ByteCodeHelper

public ByteCodeHelper(com.github.randomcodeorg.ppplugin.PContext context)

Creates a new ByteCodeHelper using the given context.

Parameters:

context - The context to be used by this ByteCodeHelper.

Method Detail

findMethod

public static javassist.CtMethod findMethod(javassist.CtClass clazz,
                                            java.lang.reflect.Method m)

Finds the Method corresponding to the given javassist CtMethod.

Parameters:

clazz - The CtClass that contains the CtMethod.

m - The reflection Method thats corresponding CtMethod should be returned.

Returns:

The CtMethod with the same name and input parameters as the given reflection Method.

getClassPool

public javassist.ClassPool getClassPool()
                                 throws javassist.NotFoundException

Returns the javassist ClassPool used by this instance.

Returns:

The javassist ClassPool used by this instance.

Throws:

javassist.NotFoundException - If the class pool could not be created.

edit

public boolean edit(javassist.CtClass cl,
                    java.lang.Class<?> runtimeClass)
             throws java.lang.IllegalStateException

Marks the given class as edited. A future call to commit() will compile and save the changes of this class.

Note: Some processors in this project (AbstractClassModificationProcessor, AbstractLoggingProcessor, ...) will call the commit() method automatically.

Parameters:

cl - The CtClass to edit.

runtimeClass - The corresponding reflection Class.

Returns:

false if the given class is already marked as edited.

Throws:

java.lang.IllegalStateException - Is thrown if there is no ClassPool for this instance. See getClassPool().

getOrCreateField

public javassist.CtField getOrCreateField(javassist.CtClass ctClass,
                                          java.lang.String typeName,
                                          java.lang.String fieldPrefix,
                                          java.lang.String visibility,
                                          boolean isStatic,
                                          boolean isFinal,
                                          java.lang.String initValue)
                                   throws javassist.CannotCompileException

Returns a existing field or creates one.

Note: This method will not call edit(CtClass, Class). One should do this himself.

Parameters:

ctClass - The CtClass that contains the field.

typeName - A string containing the canonical type of the field to return.

fieldPrefix - The prefix of the fields name.

visibility - The visibility of the field (public, private, protected).

isStatic - true if the field is static.

isFinal - true if the field is final.

initValue - The initial value of the field (4, new java.lang.Object(), new java.lang.StringBuilder()) or null.

Returns:

The found or created field.

Throws:

javassist.CannotCompileException - If the field could not be found and the creation failed.

commit

public void commit(boolean continueOnException)
            throws javassist.CannotCompileException,
                   java.io.IOException

Compiles the changes and applies them to the corresponding .class-files.

Note: Some processors in this project (AbstractClassModificationProcessor, AbstractLoggingProcessor, ...) will call the commit() method automatically.

Parameters:

continueOnException - false if the process should abort if an exception is thrown. true if the process should continue if an exception is thrown (in this case the exception will be logged).

Throws:

javassist.CannotCompileException - Is thrown if the changes could not be compiled and continueOnException is false.

java.io.IOException - Is thrown if the changes could not be written to the corresponding .class-files and continueOnException is false.

commit

public void commit()

The same as ByteCodeHelper#commit(true).

releaseResources

public void releaseResources()

Releases the resources of created by this instance.