org.apache.tapestry5.services
Interface ClassTransformation

All Superinterfaces:

AnnotationProvider

All Known Subinterfaces:

InternalClassTransformation

All Known Implementing Classes:

InternalClassTransformationImpl

public interface ClassTransformation
extends AnnotationProvider

Contains class-specific information used when transforming a raw component class into an executable component class. An executable class is one that has been transformed to work within Tapestry. This includes adding interfaces (Component) but also transforming access to fields, based on annotations and naming conventions. Most of the changes are provided by different implementations of ComponentClassTransformWorker.

Much of this information is somewhat like ordinary reflection, but applies to a class that has not yet been loaded. Field types, return types, parameter types and exception types are represented as string names, since any of them may be a class that has not yet been loaded and transformed as well.

Transformation is primarily about identifying annotations on fields and on methods and changing the class, adding new interfaces, fields and methods, and deleting some existing fields.

A ClassTransformation contains all the state data specific to a particular class being transformed. A number of workers will operate upon the ClassTransformation to effect the desired changes before the true class is loaded into memory.

Instances of this class are not designed to be thread safe, access to an instance should be restricted to a single thread. In fact, the design of this type is to allow stateless singletons in multiple threads to work on thread-specific data (within the ClassTransformation).

The majority of methods concern the declared members (field and methods) of a specific class, rather than any fields or methods inherited from a base class.

See Also:

org.apache.tapestry5.services.TapestryModule#contributeComponentClassTransformWorker(org.apache.tapestry5.ioc.OrderedConfiguration, org.apache.tapestry5.ioc.ObjectLocator, InjectionProvider, ComponentClassResolver)

Method Summary

void	addCatch(TransformMethodSignature methodSignature, String exceptionType, String body) Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.
void	addComponentEventHandler(String eventType, int minContextValues, String methodDescription, ComponentEventHandler handler) Adds advice to the Component.dispatchComponentEvent(org.apache.tapestry5.runtime.ComponentEvent) method.
String	addField(int modifiers, String type, String suggestedName) Deprecated. Use createField(int, String, String) instead
void	addImplementedInterface(Class interfaceClass) Transforms the class to implement the indicated interface.
<T> TransformField	addIndirectInjectedField(Class<T> type, String suggestedName, ComponentValueProvider<T> provider) Like addInjectedField(Class, String, Object), but instead of specifying the value, a provider for the value is specified.
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) Deprecated. Use getOrCreateMethod(TransformMethodSignature) instead. This method is non-functional as of Tapestry 5.2.
void	addTransformedMethod(TransformMethodSignature methodSignature, String methodBody) Deprecated. Use getOrCreateMethod(TransformMethodSignature) instead. This method is non-functional as of Tapestry 5.2.
void	advise(TransformMethodSignature methodSignature, ComponentMethodAdvice advice) Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead
void	claimField(String fieldName, Object tag) Deprecated. Use TransformField.claim(Object) instead
TransformField	createField(int modifiers, String type, String suggestedName) Defines a new declared field for the class.
void	extendConstructor(String statement) Deprecated. Use methods that create or inject fields (directly or indirectly)
void	extendExistingMethod(TransformMethodSignature methodSignature, String methodBody) Deprecated. Use instead. This method is non-functional as of Tapestry 5.2.
void	extendMethod(TransformMethodSignature methodSignature, String methodBody) Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.
List<String>	findFields(FieldFilter filter) Deprecated. Use matchFields(Predicate) instead
List<String>	findFieldsWithAnnotation(Class<? extends Annotation> annotationClass) Deprecated. Use matchFieldsWithAnnotation(Class) instead
List<TransformMethodSignature>	findMethods(MethodFilter filter) Deprecated. Use matchMethods(Predicate) instead
List<TransformMethodSignature>	findMethodsWithAnnotation(Class<? extends Annotation> annotationClass) Deprecated. Use matchMethodsWithAnnotation(Class) instead
List<String>	findUnclaimedFields() Deprecated. Use matchUnclaimedFields() instead
String	getClassName() Returns the fully qualified class name of the class being transformed.
TransformField	getField(String fieldName) Locates a declared field by its field name.
<T extends Annotation> T	getFieldAnnotation(String fieldName, Class<T> annotationClass) Deprecated. Use AnnotationProvider.getAnnotation(Class) instead
int	getFieldModifiers(String fieldName) Deprecated. Use TransformField.getModifiers() instead
String	getFieldType(String fieldName) Deprecated. Use TransformField.getType() instead
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 method, Class<T> annotationClass) Deprecated. Use AnnotationProvider.getAnnotation(Class) instead
String	getMethodIdentifier(TransformMethodSignature signature) Deprecated. Use TransformMethod.getMethodIdentifier() instead
TransformMethod	getOrCreateMethod(TransformMethodSignature signature) Locates and returns the method if declared in this class; If not, the method is added to the class.
String	getResourcesFieldName() Deprecated. Obtain the resources from ComponentResourcesAware.getComponentResources() or as passed to ComponentValueProvider.get(ComponentResources) instead
void	injectField(String fieldName, Object value) Deprecated. Use TransformField.inject(Object) instead
boolean	isDeclaredMethod(TransformMethodSignature signature) Determines if the class being transformed includes a declared (not inherited) method with the provided signature.
boolean	isField(String fieldName) Returns true if the indicated name is a private instance field.
boolean	isMethodOverride(TransformMethodSignature methodSignature) Deprecated. Use TransformMethod.isOverride() instead
boolean	isRootTransformation() Returns true if this transformation represents a root class (one that extends directly from Object), or false if this transformation is an sub-class of another transformed class.
void	makeReadOnly(String fieldName) Deprecated. Use TransformField.replaceAccess(TransformField) instead
List<TransformField>	matchFields(Predicate<TransformField> predicate) Finds all unclaimed fields matched by the provided predicate.
List<TransformField>	matchFieldsWithAnnotation(Class<? extends Annotation> annotationClass) Returns a sorted list of declared instance fields with the indicated annotation.
List<TransformMethod>	matchMethods(Predicate<TransformMethod> predicate) Finds all methods matched by the provided predicate.
List<TransformMethod>	matchMethodsWithAnnotation(Class<? extends Annotation> annotationType) Finds all methods matched by the provided predicate.
List<TransformField>	matchUnclaimedFields() Matches all fields that are not claimed.
String	newMemberName(String suggested) Returns the name of a new member (field or method).
String	newMemberName(String prefix, String baseName) As with newMemberName(String), but the suggested name is constructed from the prefix and base name.
void	prefixMethod(TransformMethodSignature methodSignature, String methodBody) Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.
void	removeField(String fieldName) Deprecated. This method is non-functional as of Tapestry 5.2
void	replaceReadAccess(String fieldName, String methodName) Deprecated. Use {@link TransformField#replaceAccess(ComponentValueProvider) instead
void	replaceWriteAccess(String fieldName, String methodName) Deprecated. Use {@link TransformField#replaceAccess(ComponentValueProvider) instead
Class	toClass(String type) Converts a type name into a corresponding class (possibly, a transformed class).

Methods inherited from interface org.apache.tapestry5.ioc.AnnotationProvider

getAnnotation

Method Detail

getClassName

String getClassName()

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

newMemberName

String newMemberName(String suggested)

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).

Parameters:

suggested - the suggested value for the member

Returns:

a unique name for the member

newMemberName

String newMemberName(String prefix,
                     String baseName)

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

Parameters:

prefix - for the generated name

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

Returns:

a unique name

findFieldsWithAnnotation

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

Deprecated. Use matchFieldsWithAnnotation(Class) instead

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.

matchFieldsWithAnnotation

List<TransformField> matchFieldsWithAnnotation(Class<? extends Annotation> annotationClass)

Returns a sorted list of declared instance fields with the indicated annotation. Non-private and static fields are ignored.

Since:

5.2.0

findMethodsWithAnnotation

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

Deprecated. Use matchMethodsWithAnnotation(Class) instead

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

Parameters:

annotationClass -

Returns:

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

See Also:

findMethods(MethodFilter)

findMethods

List<TransformMethodSignature> findMethods(MethodFilter filter)

Deprecated. Use matchMethods(Predicate) instead

Finds all methods matched by the provided filter.

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.

matchMethods

List<TransformMethod> matchMethods(Predicate<TransformMethod> predicate)

Finds all methods matched by the provided predicate.

Parameters:

predicate - Used to filter the list

Returns:

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

matchMethodsWithAnnotation

List<TransformMethod> matchMethodsWithAnnotation(Class<? extends Annotation> annotationType)

Finds all methods matched by the provided predicate.

Parameters:

annotationType - Used to filter the list

Returns:

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

findFields

List<String> findFields(FieldFilter filter)

Deprecated. Use matchFields(Predicate) instead

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

Parameters:

filter - passed each field name and field type

Returns:

the names of all matched fields, in ascending order

matchFields

List<TransformField> matchFields(Predicate<TransformField> predicate)

Finds all unclaimed fields matched by the provided predicate. Only considers instance fields. Added, removed and claimed fields are excluded.

Parameters:

predicate - used for matching

Returns:

sorted list of matching fields

Since:

5.2.0

getFieldAnnotation

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

Deprecated. Use AnnotationProvider.getAnnotation(Class) instead

Finds an annotation on a declared instance field.

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

Throws:

IllegalArgumentException - if the fieldName does not correspond to a declared field

getField

TransformField getField(String fieldName)

Locates a declared field by its field name. The field must exist.

Parameters:

name - of declared field

Returns:

field information

Throws:

RuntimeException - if no such field

Since:

5.2.0

getMethodAnnotation

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

Deprecated. Use AnnotationProvider.getAnnotation(Class) instead

Finds an annotation on a declared method.

Type Parameters:

T - constrains parameter and return value to Annotation types

Parameters:

method - the method signature to search

annotationClass - the type of annotation to access

Returns:

the annotation if present, or null otherwise

Throws:

IllegalArgumentException - if the method signature does not correspond to a declared method

claimField

void claimField(String fieldName,
                Object tag)

Deprecated. Use TransformField.claim(Object) instead

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.

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)

Throws:

IllegalArgumentException - if the fieldName does not correspond to a declared instance field

IllegalStateException - if the field is already claimed for some other tag

makeReadOnly

void makeReadOnly(String fieldName)

Deprecated. Use TransformField.replaceAccess(TransformField) instead

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

Parameters:

fieldName - name of field to so change

See Also:

ReadOnlyFieldValueConduit

findUnclaimedFields

List<String> findUnclaimedFields()

Deprecated. Use matchUnclaimedFields() instead

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

matchUnclaimedFields

List<TransformField> matchUnclaimedFields()

Matches all fields that are not claimed. This may include static fields and final fields, but will not include fields that have been added as part of the transformation.

Returns:

sorted list of unclaimed fields

Since:

5.2.0

getFieldType

String getFieldType(String fieldName)

Deprecated. Use TransformField.getType() instead

Obtains the type of a declared instance field.

Parameters:

fieldName -

Returns:

the type of the field, as a string

Throws:

RuntimeException - if the fieldName does not correspond to a declared instance field

isField

boolean isField(String fieldName)

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

Parameters:

fieldName -

Returns:

true if field exists

addField

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

Deprecated. Use createField(int, String, String) instead

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

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

createField

TransformField createField(int modifiers,
                           String type,
                           String suggestedName)

Defines a new declared field for the class. Suggested name may be modified to ensure uniqueness.

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:

new field instance

addInjectedField

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

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. This is primarily used to inject service dependencies into components, though it has a number of other uses as well.

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

addIndirectInjectedField

<T> TransformField addIndirectInjectedField(Class<T> type,
                                            String suggestedName,
                                            ComponentValueProvider<T> provider)

Like addInjectedField(Class, String, Object), but instead of specifying the value, a provider for the value is specified. In the generated class' constructor, the provider will be passed the ComponentResources and will return the final value; thus each component instance will receive a matching unique instance via the provider.

Type Parameters:

T -

Parameters:

type - type of value to inject

suggestedName - suggested name for the new field

provider - injected into the component to provide the value

Returns:

the actual name of the injected field

Since:

5.2.0

injectField

void injectField(String fieldName,
                 Object value)

Deprecated. Use TransformField.inject(Object) instead

Converts an existing 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.

Parameters:

fieldName - name of field to convert

value - the value provided by the field

addImplementedInterface

void addImplementedInterface(Class interfaceClass)

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.

Parameters:

interfaceClass - the interface to be implemented by the class

Throws:

IllegalArgumentException - if the interfaceClass argument does not represent an interface

extendMethod

void extendMethod(TransformMethodSignature methodSignature,
                  String methodBody)

Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.

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 body is added that first invokes the super implementation. Use 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 removeField(String) removed}, replaceReadAccess(String, String) read replaced}, or write replaced fields. Generally that's what you want!

Parameters:

methodSignature - the signature of the method to extend

methodBody - the body of code

Throws:

MethodCompileException - if the provided Javassist method body can not be compiled

extendExistingMethod

void extendExistingMethod(TransformMethodSignature methodSignature,
                          String methodBody)

Deprecated. Use instead. This method is non-functional as of Tapestry 5.2.

Like extendMethod(TransformMethodSignature, String), but the extension does not mark the method as new, and field changes will be processed. Note: at some point, this is not longer true; extend and extendMethod work identically.

Parameters:

methodSignature - signature of the method to extend

methodBody - the body of code

Throws:

MethodCompileException - if the provided method body can not be compiled

See Also:

prefixMethod(TransformMethodSignature, String)

prefixMethod

void prefixMethod(TransformMethodSignature methodSignature,
                  String methodBody)

Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.

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 addMethod(TransformMethodSignature, String) when it is necessary to control when the super-class method is invoked.

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

Parameters:

methodSignature -

methodBody -

Throws:

MethodCompileException - if the provided method body can not be compiled

getResourcesFieldName

String getResourcesFieldName()

Deprecated. Obtain the resources from ComponentResourcesAware.getComponentResources() or as passed to ComponentValueProvider.get(ComponentResources) instead

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.

Returns:

name of field

addMethod

void addMethod(TransformMethodSignature signature,
               String methodBody)

Deprecated. Use getOrCreateMethod(TransformMethodSignature) instead. This method is non-functional as of Tapestry 5.2.

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 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.

addTransformedMethod

void addTransformedMethod(TransformMethodSignature methodSignature,
                          String methodBody)

Deprecated. Use getOrCreateMethod(TransformMethodSignature) instead. This method is non-functional as of Tapestry 5.2.

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

extendConstructor

void extendConstructor(String statement)

Deprecated. Use methods that create or inject fields (directly or indirectly)

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

Parameters:

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

See Also:

ComponentValueProvider

replaceReadAccess

void replaceReadAccess(String fieldName,
                       String methodName)

Deprecated. Use {@link TransformField#replaceAccess(ComponentValueProvider) instead

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

replaceWriteAccess

void replaceWriteAccess(String fieldName,
                        String methodName)

Deprecated. Use {@link TransformField#replaceAccess(ComponentValueProvider) instead

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 addMethod(TransformMethodSignature, String) or extendMethod(TransformMethodSignature, String).

removeField

void removeField(String fieldName)

Deprecated. This method is non-functional as of Tapestry 5.2

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

Parameters:

fieldName - the name of the field to remove

See Also:

replaceReadAccess(String, String), replaceWriteAccess(String, String)

toClass

Class toClass(String type)

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

getLogger

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.

getFieldModifiers

int getFieldModifiers(String fieldName)

Deprecated. Use TransformField.getModifiers() instead

Returns the modifiers for the named field.

getMethodIdentifier

String getMethodIdentifier(TransformMethodSignature signature)

Deprecated. Use TransformMethod.getMethodIdentifier() instead

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).

Parameters:

signature -

Returns:

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

isRootTransformation

boolean isRootTransformation()

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

Returns:

true if root class, false if sub-class

addCatch

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

Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead. This method is non-functional as of Tapestry 5.2.

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.

Parameters:

methodSignature - method to be extended.

exceptionType - fully qualified class name of exception

body - code to execute

advise

void advise(TransformMethodSignature methodSignature,
            ComponentMethodAdvice advice)

Deprecated. Use TransformMethod.addAdvice(ComponentMethodAdvice) instead

Adds method advice for the indicated method.

isMethodOverride

boolean isMethodOverride(TransformMethodSignature methodSignature)

Deprecated. Use TransformMethod.isOverride() instead

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

Parameters:

methodSignature - signature of method to check

Returns:

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

getOrCreateMethod

TransformMethod getOrCreateMethod(TransformMethodSignature signature)

Locates and returns the method if declared in this class; If not, the method is added to the class. If the method is an override of a base class method, then the method will delegate to the base class method (invoke it, return its value). If the method is entirely new, it will ignore its parameters and return a default value (null, 0 or false).

Parameters:

signature - identifies the method to locate, override or create

Since:

5.2.0

isDeclaredMethod

boolean isDeclaredMethod(TransformMethodSignature signature)

Determines if the class being transformed includes a declared (not inherited) method with the provided signature.

Parameters:

signature - identifies method to search for

Returns:

true if a such a method exists

Since:

5.2.0

addComponentEventHandler

void addComponentEventHandler(String eventType,
                              int minContextValues,
                              String methodDescription,
                              ComponentEventHandler handler)

Adds advice to the Component.dispatchComponentEvent(org.apache.tapestry5.runtime.ComponentEvent) method. If the handler is invoked, the return value of the method will be overriden to true. Updates the model to indicate that there is a handler for the named event. Existing handlers, or super-class handlers, are invoked first.

Parameters:

eventType - name of event to be handled

minContextValues - minimum number of event context values required to invoke the method

methodDescription - Text description of what the handler does (used with Event.setMethodDescription(String))

handler - the handler to invoke

Since:

5.2.0