org.apache.tapestry5.internal.services
Class InternalClassTransformationImpl

java.lang.Object
  org.apache.tapestry5.internal.services.InternalClassTransformationImpl

All Implemented Interfaces:

InternalClassTransformation, AnnotationProvider, ClassTransformation

public final class InternalClassTransformationImpl
extends Object
implements InternalClassTransformation

Implementation of the InternalClassTransformation interface.

Constructor Summary

InternalClassTransformationImpl(ClassFactory classFactory, javassist.CtClass ctClass, ComponentClassCache componentClassCache, ComponentModel componentModel, CtClassSource classSource)
This is a constructor for a base class.

Method Summary

void	addCatch(TransformMethodSignature methodSignature, String exceptionType, String body) Adds a catch block to the method.
String	addField(int modifiers, String type, String suggestedName) Defines a new declared field for the class.
void	addImplementedInterface(Class interfaceClass) Transforms the class to implement the indicated interface.
String	addInjectedField(Class type, String suggestedName, Object value) Defines a new protected instance variable whose initial value is provided statically, via a constructor parameter.
void	addMethod(TransformMethodSignature signature, String methodBody) Adds a new method to the transformed class.
void	addTransformedMethod(TransformMethodSignature signature, String methodBody) As with ClassTransformation.addMethod(TransformMethodSignature, String), but field references inside the method will be transformed, and the method must not already exist.
void	advise(TransformMethodSignature methodSignature, ComponentMethodAdvice advice) Adds method advice for the indicated method.
void	claimField(String fieldName, Object tag) Claims a field so as to ensure that only a single annotation is applied to any single field.
void	copyMethod(TransformMethodSignature sourceMethod, int modifiers, String newMethodName) Creates a new method by copying the body of an existing method.
InternalClassTransformation	createChildTransformation(javassist.CtClass childClass, MutableComponentModel childModel)
Instantiator	createInstantiator() Called (after InternalClassTransformation.finish()) to construct an instantiator for the component.
void	extendConstructor(String statement) Adds a statement to the constructor.
void	extendExistingMethod(TransformMethodSignature methodSignature, String methodBody) Like ClassTransformation.extendMethod(TransformMethodSignature, String), but the extension does not mark the method as new, and field changes will be processed.
void	extendMethod(TransformMethodSignature methodSignature, String methodBody) Extends an existing method.
List<String>	findFields(FieldFilter filter) Finds all unclaimed fields matched by the provided filter.
List<String>	findFieldsWithAnnotation(Class<? extends Annotation> annotationClass) Generates a list of the names of declared instance fields that have the indicated annotation.
List<TransformMethodSignature>	findMethods(MethodFilter filter) Finds all methods matched by the provided filter.
List<TransformMethodSignature>	findMethodsWithAnnotation(Class<? extends Annotation> annotationClass) Finds all methods defined in the class that are marked with the provided annotation.
List<String>	findUnclaimedFields() Finds any declared instance fields that have not been claimed (via ClassTransformation.claimField(String, Object)) and returns the names of those fields.
void	finish() Invoked after all ComponentClassTransformWorkers have had their chance to work over the class.
<T extends Annotation> T	getAnnotation(Class<T> annotationClass) Searches for the specified annotation, returning the matching annotation instance.
List<Annotation>	getClassAnnotations()
String	getClassName() Returns the fully qualified class name of the class being transformed.
List<ConstructorArg>	getConstructorArgs() Returns a copy of the list of constructor arguments for this class.
<T extends Annotation> T	getFieldAnnotation(String fieldName, Class<T> annotationClass) Finds an annotation on a declared instance field.
int	getFieldModifiers(String fieldName) Returns the modifiers for the named field.
String	getFieldType(String fieldName) Obtains the type of a declared instance field.
IdAllocator	getIdAllocator() Returns a copy of the transformation's IdAllocator.
org.slf4j.Logger	getLogger() Returns a logger, based on the class name being transformed, to which warnings or errors concerning the class being transformed may be logged.
<T extends Annotation> T	getMethodAnnotation(TransformMethodSignature signature, Class<T> annotationClass) Finds an annotation on a declared method.
String	getMethodIdentifier(TransformMethodSignature signature) Converts a signature to a string used to identify the method; this consists of the TransformMethodSignature.getMediumDescription() appended with source file information and line number information (when available).
InternalClassTransformation	getParentTransformation() Returns the parent transformation, or null for a root class.
String	getResourcesFieldName() Returns the name of a field that provides the ComponentResources for the transformed component.
void	injectField(String fieldName, Object value) Converts the field into a read only field whose value is the provided value.
boolean	isField(String fieldName) Returns true if the indicated name is a private instance field.
boolean	isMethod(TransformMethodSignature signature) Returns true if the provided signature is a method implemented by the transformed class.
boolean	isMethodOverride(TransformMethodSignature methodSignature) Returns true if the method is an override of a method from the parent class.
boolean	isRootTransformation() Returns true if this transformation represents a root class (one that extends directly from Object), or false if this transformation is an extension of another transformed class.
void	makeReadOnly(String fieldName) Changes the field to be read only.
String	newMemberName(String suggested) Returns the name of a new member (field or method).
String	newMemberName(String prefix, String baseName) As with ClassTransformation.newMemberName(String), but the suggested name is constructed from the prefix and base name.
void	prefixMethod(TransformMethodSignature methodSignature, String methodBody) Inserts code at the beginning of a method body (i.e.
void	removeField(String fieldName) Removes a field entirely; this is useful for fields that are replaced entirely by computed values.
void	replaceReadAccess(String fieldName, String methodName) Replaces all read-references to the specified field with invocations of the specified method name.
void	replaceWriteAccess(String fieldName, String methodName) Replaces all write accesses to the specified field with invocations of the specified method name.
String	searchForPreviousInjection(InjectionKey key) Searchs for an existing injection of an object, returning the name of the protected field into which the value was injected.
Class	toClass(String type) Converts a type name into a corresponding class (possibly, a transformed class).
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

InternalClassTransformationImpl

public InternalClassTransformationImpl(ClassFactory classFactory,
                                       javassist.CtClass ctClass,
                                       ComponentClassCache componentClassCache,
                                       ComponentModel componentModel,
                                       CtClassSource classSource)

This is a constructor for a base class.

Method Detail

createChildTransformation

public InternalClassTransformation createChildTransformation(javassist.CtClass childClass,
                                                             MutableComponentModel childModel)

Specified by:

createChildTransformation in interface InternalClassTransformation

getResourcesFieldName

public String getResourcesFieldName()

Description copied from interface: ClassTransformation

Returns the name of a field that provides the ComponentResources for the transformed component. This will be a protected field, accessible to the class and subclasses.

Specified by:

getResourcesFieldName in interface ClassTransformation

Returns:

name of field

getFieldAnnotation

public <T extends Annotation> T getFieldAnnotation(String fieldName,
                                                   Class<T> annotationClass)

Description copied from interface: ClassTransformation

Finds an annotation on a declared instance field.

Specified by:

getFieldAnnotation in interface ClassTransformation

Type Parameters:

T - constrains parameter and return value to Annotation types

Parameters:

fieldName - the name of the field, which must exist

annotationClass - the type of annotation to access

Returns:

the annotation if present, or null otherwise

getMethodAnnotation

public <T extends Annotation> T getMethodAnnotation(TransformMethodSignature signature,
                                                    Class<T> annotationClass)

Description copied from interface: ClassTransformation

Finds an annotation on a declared method.

Specified by:

getMethodAnnotation in interface ClassTransformation

Type Parameters:

T - constrains parameter and return value to Annotation types

Parameters:

signature - the method signature to search

annotationClass - the type of annotation to access

Returns:

the annotation if present, or null otherwise

getAnnotation

public <T extends Annotation> T getAnnotation(Class<T> annotationClass)

Description copied from interface: AnnotationProvider

Searches for the specified annotation, returning the matching annotation instance.

Specified by:

getAnnotation in interface AnnotationProvider

Parameters:

annotationClass - used to select the annotation to return�

Returns:

the annotation, or null if not found

newMemberName

public String newMemberName(String suggested)

Description copied from interface: ClassTransformation

Returns the name of a new member (field or method). Ensures that the resulting name does not conflict with any existing member (declared by the underlying class, or inherited from a base class).

Specified by:

newMemberName in interface ClassTransformation

Parameters:

suggested - the suggested value for the member

Returns:

a unique name for the member

newMemberName

public String newMemberName(String prefix,
                            String baseName)

Description copied from interface: ClassTransformation

As with ClassTransformation.newMemberName(String), but the suggested name is constructed from the prefix and base name. An underscore will seperate the prefix from the base name.

Specified by:

newMemberName in interface ClassTransformation

Parameters:

prefix - for the generated name

baseName - an name, often of an existing field or method

Returns:

a unique name

addImplementedInterface

public void addImplementedInterface(Class interfaceClass)

Description copied from interface: ClassTransformation

Transforms the class to implement the indicated interface. If the class (or its super class) does not already implement the interface, then the interface is added, and default implementations of any methods of the interface are added.

TODO: Checking that the names of methods in the interface do not conflict with the names of methods present in the (unmodified) class.

Specified by:

addImplementedInterface in interface ClassTransformation

Parameters:

interfaceClass - the interface to be implemented by the class

claimField

public void claimField(String fieldName,
                       Object tag)

Description copied from interface: ClassTransformation

Claims a field so as to ensure that only a single annotation is applied to any single field. When a transformation occurs (driven by a field annotation), the field is claimed (using the annotation object as the tag). If a field has multiple conflicting annotations, this will be discovered when the code attempts to claim the field a second time.

Specified by:

claimField in interface ClassTransformation

Parameters:

fieldName - the name of the field that is being claimed

tag - a non-null object that represents why the field is being tagged (this is typically a specific annotation on the field)

addMethod

public void addMethod(TransformMethodSignature signature,
                      String methodBody)

Description copied from interface: ClassTransformation

Adds a new method to the transformed class. Replaces any existing method declared for the class. When overriding a super-class method, you should use ClassTransformation.extendMethod(TransformMethodSignature, String), or you should remember to invoke the super class implemetation explicitly. Use this method to control when the super-class implementation is invoked.

Specified by:

addMethod in interface ClassTransformation

addTransformedMethod

public void addTransformedMethod(TransformMethodSignature signature,
                                 String methodBody)

Description copied from interface: ClassTransformation

As with ClassTransformation.addMethod(TransformMethodSignature, String), but field references inside the method will be transformed, and the method must not already exist.

Specified by:

addTransformedMethod in interface ClassTransformation

extendMethod

public void extendMethod(TransformMethodSignature methodSignature,
                         String methodBody)

Description copied from interface: ClassTransformation

Extends an existing method. The provided method body is inserted at the end of the existing method (i.e. CtBehavior.insertAfter(java.lang.String)). To access or change the return value, use the $_ pseudo variable.

The method may be declared in the class, or may be inherited from a super-class. For inherited methods, a method is added that first invokes the super implementation. Use ClassTransformation.addMethod(TransformMethodSignature, String) when it is necessary to control when the super-class method is invoked.

The extended method is considered new. New methods are not scanned for ClassTransformation.removeField(String) removed}, ClassTransformation.replaceReadAccess(String, String) read replaced}, or write replaced fields. Generally that's what you want!

Specified by:

extendMethod in interface ClassTransformation

Parameters:

methodSignature - the signature of the method to extend

methodBody - the body of code

See Also:

ClassTransformation.extendExistingMethod(TransformMethodSignature, String)

extendExistingMethod

public void extendExistingMethod(TransformMethodSignature methodSignature,
                                 String methodBody)

Description copied from interface: ClassTransformation

Like ClassTransformation.extendMethod(TransformMethodSignature, String), but the extension does not mark the method as new, and field changes will be processed.

Specified by:

extendExistingMethod in interface ClassTransformation

Parameters:

methodSignature - signature of the method to extend

methodBody - the body of code

See Also:

ClassTransformation.prefixMethod(TransformMethodSignature, String)

copyMethod

public void copyMethod(TransformMethodSignature sourceMethod,
                       int modifiers,
                       String newMethodName)

Description copied from interface: InternalClassTransformation

Creates a new method by copying the body of an existing method. This is part of the scheme for providing method advice.

Specified by:

copyMethod in interface InternalClassTransformation

Parameters:

sourceMethod - method to be copied

modifiers - modifiers for the new method

newMethodName - name of new method to create

addCatch

public void addCatch(TransformMethodSignature methodSignature,
                     String exceptionType,
                     String body)

Description copied from interface: ClassTransformation

Adds a catch block to the method. The body should end with a return or a throw. The special Javassist variable $e is the exception instance.

Specified by:

addCatch in interface ClassTransformation

Parameters:

methodSignature - method to be extended.

exceptionType - fully qualified class name of exception

body - code to execute

prefixMethod

public void prefixMethod(TransformMethodSignature methodSignature,
                         String methodBody)

Description copied from interface: ClassTransformation

Inserts code at the beginning of a method body (i.e. CtBehavior.insertBefore(String).

The method may be declared in the class, or may be inherited from a super-class. For inherited methods, a method is added that first invokes the super implementation. Use ClassTransformation.addMethod(TransformMethodSignature, String) when it is necessary to control when the super-class method is invoked.

Like ClassTransformation.extendExistingMethod(TransformMethodSignature, String), this method is generally used to "wrap" an existing method adding additional functionality such as caching or transaction support.

Specified by:

prefixMethod in interface ClassTransformation

findFieldsWithAnnotation

public List<String> findFieldsWithAnnotation(Class<? extends Annotation> annotationClass)

Description copied from interface: ClassTransformation

Generates a list of the names of declared instance fields that have the indicated annotation. Non-private and static fields are ignored. Only the names of private instance fields are returned.

Specified by:

findFieldsWithAnnotation in interface ClassTransformation

findFields

public List<String> findFields(FieldFilter filter)

Description copied from interface: ClassTransformation

Finds all unclaimed fields matched by the provided filter. Only considers private instance fields.

Specified by:

findFields in interface ClassTransformation

Parameters:

filter - passed each field name and field type

Returns:

the names of all matched fields, in ascending order

findMethodsWithAnnotation

public List<TransformMethodSignature> findMethodsWithAnnotation(Class<? extends Annotation> annotationClass)

Description copied from interface: ClassTransformation

Finds all methods defined in the class that are marked with the provided annotation.

Specified by:

findMethodsWithAnnotation in interface ClassTransformation

Returns:

a list of method signature (which may be empty) in ascending order

See Also:

ClassTransformation.findMethods(MethodFilter)

findMethods

public List<TransformMethodSignature> findMethods(MethodFilter filter)

Description copied from interface: ClassTransformation

Finds all methods matched by the provided filter.

Specified by:

findMethods in interface ClassTransformation

Parameters:

filter - Passed each method signature, it may include or exclude each potential

Returns:

a list of matching method signatures (which may be empty) in ascending order (by method name), but descending order (by parameter count) within overrides of a single method name.

findUnclaimedFields

public List<String> findUnclaimedFields()

Description copied from interface: ClassTransformation

Finds any declared instance fields that have not been claimed (via ClassTransformation.claimField(String, Object)) and returns the names of those fields. May return an empty array.

Specified by:

findUnclaimedFields in interface ClassTransformation

getFieldType

public String getFieldType(String fieldName)

Description copied from interface: ClassTransformation

Obtains the type of a declared instance field.

Specified by:

getFieldType in interface ClassTransformation

Returns:

the type of the field, as a string

isField

public boolean isField(String fieldName)

Description copied from interface: ClassTransformation

Returns true if the indicated name is a private instance field.

Specified by:

isField in interface ClassTransformation

Returns:

true if field exists

getFieldModifiers

public int getFieldModifiers(String fieldName)

Description copied from interface: ClassTransformation

Returns the modifiers for the named field.

Specified by:

getFieldModifiers in interface ClassTransformation

addField

public String addField(int modifiers,
                       String type,
                       String suggestedName)

Description copied from interface: ClassTransformation

Defines a new declared field for the class. The suggestedName may be modified to ensure uniqueness.

Specified by:

addField in interface ClassTransformation

Parameters:

modifiers - modifiers for the field (typically, Modifier.PRIVATE)

type - the type for the field, as a string

suggestedName - the desired name for the field, which may be modified (for uniqueness) when returned

Returns:

the (uniqued) name for the field

addInjectedField

public String addInjectedField(Class type,
                               String suggestedName,
                               Object value)

Description copied from interface: ClassTransformation

Defines a new protected instance variable whose initial value is provided statically, via a constructor parameter. The transformation caches the result, so calling this method repeatedly with the same type and value will return the same field name. Caching extends to the parent transformation, so that a value injected into a parent class will be available (via the protected instance variable) to subclasses.

Specified by:

addInjectedField in interface ClassTransformation

Parameters:

type - the type of object to inject

suggestedName - the suggested name for the new field

value - to be injected. This value is retained.

Returns:

the actual name of the injected field

searchForPreviousInjection

public String searchForPreviousInjection(InjectionKey key)

Description copied from interface: InternalClassTransformation

Searchs for an existing injection of an object, returning the name of the protected field into which the value was injected.

TODO: Howard sayz: Uggh! At least define a real key (MultiKey is intended for internal use, never part of an API). Is this necessary? The cost of re-injection is tiny.

Specified by:

searchForPreviousInjection in interface InternalClassTransformation

advise

public void advise(TransformMethodSignature methodSignature,
                   ComponentMethodAdvice advice)

Description copied from interface: ClassTransformation

Adds method advice for the indicated method.

Specified by:

advise in interface ClassTransformation

isMethodOverride

public boolean isMethodOverride(TransformMethodSignature methodSignature)

Description copied from interface: ClassTransformation

Returns true if the method is an override of a method from the parent class.

Specified by:

isMethodOverride in interface ClassTransformation

Parameters:

methodSignature - signature of method to check

Returns:

true if the parent class contains a method with the name signature

getParentTransformation

public InternalClassTransformation getParentTransformation()

Description copied from interface: InternalClassTransformation

Returns the parent transformation, or null for a root class.

Specified by:

getParentTransformation in interface InternalClassTransformation

isMethod

public boolean isMethod(TransformMethodSignature signature)

Description copied from interface: InternalClassTransformation

Returns true if the provided signature is a method implemented by the transformed class.

Specified by:

isMethod in interface InternalClassTransformation

Returns:

true if implemented

injectField

public void injectField(String fieldName,
                        Object value)

Description copied from interface: ClassTransformation

Converts the field into a read only field whose value is the provided value. This is used when converting an existing field into a read-only injected value.

Specified by:

injectField in interface ClassTransformation

Parameters:

fieldName - name of field to convert

value - the value provided by the field

finish

public void finish()

Description copied from interface: InternalClassTransformation

Invoked after all ComponentClassTransformWorkers have had their chance to work over the class. This performs any final operations for the class transformation, which includes coming up with the final constructor method for the class.

Specified by:

finish in interface InternalClassTransformation

createInstantiator

public Instantiator createInstantiator()

Description copied from interface: InternalClassTransformation

Called (after InternalClassTransformation.finish()) to construct an instantiator for the component.

Specified by:

createInstantiator in interface InternalClassTransformation

Returns:

the component's instantiator

getIdAllocator

public IdAllocator getIdAllocator()

Description copied from interface: InternalClassTransformation

Returns a copy of the transformation's IdAllocator. Used when creating a child class transformation. May only be invoked on a frozen transformation.

Specified by:

getIdAllocator in interface InternalClassTransformation

getConstructorArgs

public List<ConstructorArg> getConstructorArgs()

Description copied from interface: InternalClassTransformation

Returns a copy of the list of constructor arguments for this class.

Specified by:

getConstructorArgs in interface InternalClassTransformation

getClassAnnotations

public List<Annotation> getClassAnnotations()

toString

public String toString()

Overrides:

toString in class Object

makeReadOnly

public void makeReadOnly(String fieldName)

Description copied from interface: ClassTransformation

Changes the field to be read only. Any existing code that changes the field will cause a runtime exception.

Specified by:

makeReadOnly in interface ClassTransformation

Parameters:

fieldName - name of field to so change

removeField

public void removeField(String fieldName)

Description copied from interface: ClassTransformation

Removes a field entirely; this is useful for fields that are replaced entirely by computed values.

Specified by:

removeField in interface ClassTransformation

Parameters:

fieldName - the name of the field to remove

See Also:

ClassTransformation.replaceReadAccess(String, String), ClassTransformation.replaceWriteAccess(String, String)

replaceReadAccess

public void replaceReadAccess(String fieldName,
                              String methodName)

Description copied from interface: ClassTransformation

Replaces all read-references to the specified field with invocations of the specified method name. Replacements do not occur in methods added via ClassTransformation.addMethod(TransformMethodSignature, String) or ClassTransformation.extendMethod(TransformMethodSignature, String).

Specified by:

replaceReadAccess in interface ClassTransformation

replaceWriteAccess

public void replaceWriteAccess(String fieldName,
                               String methodName)

Description copied from interface: ClassTransformation

Replaces all write accesses to the specified field with invocations of the specified method name. The method should take a single parameter of the same type as the field. Replacements do not occur in methods added via ClassTransformation.addMethod(TransformMethodSignature, String) or ClassTransformation.extendMethod(TransformMethodSignature, String).

Specified by:

replaceWriteAccess in interface ClassTransformation

toClass

public Class toClass(String type)

Description copied from interface: ClassTransformation

Converts a type name into a corresponding class (possibly, a transformed class). Primitive type names are returned as wrapper types.

Specified by:

toClass in interface ClassTransformation

getClassName

public String getClassName()

Description copied from interface: ClassTransformation

Returns the fully qualified class name of the class being transformed.

Specified by:

getClassName in interface ClassTransformation

getLogger

public org.slf4j.Logger getLogger()

Description copied from interface: ClassTransformation

Returns a logger, based on the class name being transformed, to which warnings or errors concerning the class being transformed may be logged.

Specified by:

getLogger in interface ClassTransformation

extendConstructor

public void extendConstructor(String statement)

Description copied from interface: ClassTransformation

Adds a statement to the constructor. The statement is added as is, though a newline is added.

Specified by:

extendConstructor in interface ClassTransformation

Parameters:

statement - the statement to add, which should end with a semicolon

getMethodIdentifier

public String getMethodIdentifier(TransformMethodSignature signature)

Description copied from interface: ClassTransformation

Converts a signature to a string used to identify the method; this consists of the TransformMethodSignature.getMediumDescription() appended with source file information and line number information (when available).

Specified by:

getMethodIdentifier in interface ClassTransformation

Returns:

a string that identifies the class, method name, types of parameters, source file and source line number

isRootTransformation

public boolean isRootTransformation()

Description copied from interface: ClassTransformation

Returns true if this transformation represents a root class (one that extends directly from Object), or false if this transformation is an extension of another transformed class.

Specified by:

isRootTransformation in interface ClassTransformation

Returns:

true if root class, false if sub-class