org.apache.avalon.fortress.impl.factory
Class BCELCodeGenerator

java.lang.Object
  org.apache.avalon.fortress.impl.factory.BCELCodeGenerator

public final class BCELCodeGenerator
extends java.lang.Object

BCELCodeGenerator creates implementations for the Methods and Fields needed in creating a WrapperClass.

Author:

Avalon Development Team

Nested Class Summary

private static class

BCELCodeGenerator.MethodDesc

Field Summary

private static java.lang.String	ACCESSOR_METHOD_NAME The name of the field accessor used to ask the generated wrapper for the wrapped class instance.
private org.apache.bcel.generic.ClassGen	m_classGenerator The ClassGen instance to use for code generation.
private org.apache.bcel.classfile.JavaClass	m_classToWrap Class object holding the type of the object we want to create a wrapper for.
private org.apache.bcel.generic.Type	m_classToWrapType The Type of the class we want to create a wrapper for.
private org.apache.bcel.generic.ConstantPoolGen	m_constPoolGenerator The ConstantPoolGen instance to use for code generation.
private org.apache.bcel.generic.InstructionFactory	m_instructionFactory The InstructionFactory to use during code gereration.
private org.apache.bcel.generic.InstructionList	m_instructionList The InstructionList instance to use during code generation.
private boolean	m_isInitialized Flag indicating whether this instance is already initialized or not.
private java.lang.String	m_wrapperClassName The name of the wrapper class to be created.
private java.lang.String	m_wrapperSuperclassName The name of the superclass of the wrapper class to be generated.
private static java.lang.String	WRAPPED_CLASS_FN The name of the field holding the wrapped class in the generated wrapper, e.g.

Constructor Summary

BCELCodeGenerator()
Default constructor.

Method Summary

org.apache.bcel.classfile.Method	createDefaultConstructor() Create the wrapper class' default constructor:
org.apache.bcel.classfile.Method[]	createImplementation(org.apache.bcel.classfile.JavaClass[] interfacesToImplement) Creates an implementation for the supplied JavaClass instance representing an interface.
org.apache.bcel.classfile.Method	createMethodWrapper(BCELCodeGenerator.MethodDesc meth) Create a method declaration/definition of the form
org.apache.bcel.classfile.Method	createMethodWrapper(org.apache.bcel.classfile.Method methodToWrap) Create a method declaration/definition of the form
org.apache.bcel.classfile.Method	createWrappedClassAccessor() Create a field accessor for the wrapped class instance of the form
org.apache.bcel.classfile.Field	createWrappedClassField() Create a field declaration of the form
private org.apache.bcel.classfile.Method	extractMethod(org.apache.bcel.generic.MethodGen mg) Extracts the Method out of the supplied MethodGen instance, clears the InstructionList and returns the extracted Method.
(package private) static BCELCodeGenerator.MethodDesc[]	extractMethods(org.apache.bcel.classfile.JavaClass[] interfacesToImplement) Extracts the collection of Methods declared in the supplied JavaClass instance.
private static void	extractMethods(org.apache.bcel.classfile.JavaClass interfaceToImplement, java.util.Set methods)
private void	findImplementation(BCELCodeGenerator.MethodDesc meth)
void	init(java.lang.String wrapperClassName, java.lang.String wrapperSuperclassName, org.apache.bcel.classfile.JavaClass classToWrap, org.apache.bcel.generic.ClassGen classGenerator)
private boolean	isInitialized() Has this instance already been initialized?

Methods inherited from class java.lang.Object

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

Field Detail

WRAPPED_CLASS_FN

private static final java.lang.String WRAPPED_CLASS_FN

The name of the field holding the wrapped class in the generated wrapper, e.g.

  
      private final  WRAPPED_CLASS_FN;
  
 

See Also:

Constant Field Values

ACCESSOR_METHOD_NAME

private static final java.lang.String ACCESSOR_METHOD_NAME

The name of the field accessor used to ask the generated wrapper for the wrapped class instance.

See Also:

Constant Field Values

m_wrapperClassName

private java.lang.String m_wrapperClassName

The name of the wrapper class to be created.

m_wrapperSuperclassName

private java.lang.String m_wrapperSuperclassName

The name of the superclass of the wrapper class to be generated.

m_classToWrap

private org.apache.bcel.classfile.JavaClass m_classToWrap

Class object holding the type of the object we want to create a wrapper for.

m_classToWrapType

private org.apache.bcel.generic.Type m_classToWrapType

The Type of the class we want to create a wrapper for.

m_classGenerator

private org.apache.bcel.generic.ClassGen m_classGenerator

The ClassGen instance to use for code generation.

m_constPoolGenerator

private org.apache.bcel.generic.ConstantPoolGen m_constPoolGenerator

The ConstantPoolGen instance to use for code generation.

m_instructionList

private final org.apache.bcel.generic.InstructionList m_instructionList

The InstructionList instance to use during code generation.

m_instructionFactory

private org.apache.bcel.generic.InstructionFactory m_instructionFactory

The InstructionFactory to use during code gereration.

m_isInitialized

private boolean m_isInitialized

Flag indicating whether this instance is already initialized or not.

Constructor Detail

BCELCodeGenerator

public BCELCodeGenerator()

Default constructor.

Method Detail

init

public void init(java.lang.String wrapperClassName,
                 java.lang.String wrapperSuperclassName,
                 org.apache.bcel.classfile.JavaClass classToWrap,
                 org.apache.bcel.generic.ClassGen classGenerator)
          throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

createWrappedClassField

public org.apache.bcel.classfile.Field createWrappedClassField()
                                                        throws java.lang.IllegalStateException

Create a field declaration of the form

  
      private  WRAPPED_CLASS_FN;
  
 

Returns:

Field

Throws:

java.lang.IllegalStateException - If this instance is not initialized.

createDefaultConstructor

public org.apache.bcel.classfile.Method createDefaultConstructor()
                                                          throws java.lang.IllegalStateException

Create the wrapper class' default constructor:

  
      public ( classToWrap)
      {
          this. = classToWrap;
      }
  
 

Returns:

The created default constructor

Throws:

java.lang.IllegalStateException - If this instance is not initialized.

createWrappedClassAccessor

public org.apache.bcel.classfile.Method createWrappedClassAccessor()
                                                            throws java.lang.IllegalStateException

Create a field accessor for the wrapped class instance of the form

  
      public Object ()
      {
          return this.;
      }
  
 

Returns:

Method

Throws:

java.lang.IllegalStateException

createMethodWrapper

public org.apache.bcel.classfile.Method createMethodWrapper(BCELCodeGenerator.MethodDesc meth)
                                                     throws java.lang.IllegalArgumentException,
                                                            java.lang.IllegalStateException

Create a method declaration/definition of the form

  
      public  ()
          throws 
      {
          return this..();
      }
  
 

Parameters:

meth - The method descriptor

Returns:

Method The Method object representing the created method

Throws:

java.lang.IllegalArgumentException - If any of the parameters passed in is null.

java.lang.IllegalStateException - If this instance is not initialized.

findImplementation

private void findImplementation(BCELCodeGenerator.MethodDesc meth)

createMethodWrapper

public org.apache.bcel.classfile.Method createMethodWrapper(org.apache.bcel.classfile.Method methodToWrap)
                                                     throws java.lang.IllegalArgumentException,
                                                            java.lang.IllegalStateException

Create a method declaration/definition of the form

  
      public  ()
          throws 
      {
          return this..();
      }
  
 

Parameters:

methodToWrap - The Method to create a wrapper for.

Returns:

Method The wrapper method.

Throws:

java.lang.IllegalArgumentException - If methodToWrao is null.

java.lang.IllegalStateException - If this instance is not initialized.

createImplementation

public org.apache.bcel.classfile.Method[] createImplementation(org.apache.bcel.classfile.JavaClass[] interfacesToImplement)
                                                        throws java.lang.Exception

Creates an implementation for the supplied JavaClass instance representing an interface.

Parameters:

interfacesToImplement - The interfaces we want to create an implementation for

Returns:

Method[] An array of Method instances representing the interface implementation.

Throws:

java.lang.IllegalArgumentException - If interfaceToImplement is null or does not represent an interface

java.lang.IllegalStateException - If this instance has not been initialized

java.lang.Exception

extractMethod

private org.apache.bcel.classfile.Method extractMethod(org.apache.bcel.generic.MethodGen mg)

Extracts the Method out of the supplied MethodGen instance, clears the InstructionList and returns the extracted Method.

Parameters:

mg - The MethodGen instance holding the Method to extract

Returns:

The extracted Method

isInitialized

private boolean isInitialized()

Has this instance already been initialized?

Returns:

TRUE, if this instance has already been initialized, FALSE otherwise

extractMethods

static BCELCodeGenerator.MethodDesc[] extractMethods(org.apache.bcel.classfile.JavaClass[] interfacesToImplement)
                                              throws java.lang.Exception

Extracts the collection of Methods declared in the supplied JavaClass instance. This instance is supposed to represent an interface.

Parameters:

interfacesToImplement - The JavaClass instances representing the interfaces we are asking for its methods.

Returns:

MethodDesc[] The array of Methods declared by the interface

Throws:

java.lang.IllegalArgumentException - If interfaceToImplement does not represent an interface

java.lang.NullPointerException - if the interfaceToImplement is null

java.lang.Exception

extractMethods

private static final void extractMethods(org.apache.bcel.classfile.JavaClass interfaceToImplement,
                                         java.util.Set methods)