net.sf.morph.transform.transformers
Class SimpleDelegatingTransformer

java.lang.Object
  net.sf.morph.transform.transformers.BaseTransformer
      net.sf.morph.transform.transformers.BaseCompositeTransformer
          net.sf.morph.transform.transformers.SimpleDelegatingTransformer

All Implemented Interfaces:

java.lang.Cloneable, net.sf.composite.Component, net.sf.composite.Composite, net.sf.composite.SimpleComposite, net.sf.composite.SpecializableComposite, net.sf.composite.StrictlyTypedComposite, Converter, Copier, DecoratedConverter, DecoratedCopier, DecoratedTransformer, ExplicitTransformer, ImpreciseTransformer, Transformer

Direct Known Subclasses:

DefaultToBooleanConverter, DefaultToTextConverter, TypeChangingGraphTransformer

public class SimpleDelegatingTransformer
extends BaseCompositeTransformer
implements net.sf.composite.SpecializableComposite, ExplicitTransformer, Transformer, DecoratedCopier, DecoratedConverter, java.lang.Cloneable, ImpreciseTransformer

Delegates transformations to a list of transformers. The transformers are tried in the order in which they appear in the components property of this transformer.

By default this transformer is initialized with a set of transformers that will meet basic needs. This list of transformers is subject to change in future versions of Morph, but we do not anticipate removing transformers, only adding new ones or modifying existing ones. This means if a transformation works in an older version of Morph it will also work in a newer version. A transformation's behavior may in some cases change between releases, but we will avoid this whenever possible.

The default set of transformers includes both converters and copiers. For calls to copy methods, only the copiers will be used. For calls to convert methods, the converters and the copiers will be used, since all Copiers provided by the Morph framework are also Converters.

Any delegates which implement NodeCopier will automatically have this transformer marked as the parent transformer. This is important for performing deep copies of object graphs. Note that it is safe for a SimpleDelegatingTransformer to implement the NodeCopier interface only if all its components do so.

Since:

Dec 12, 2004

Author:

Matt Sgarlata

Field Summary

Fields inherited from class net.sf.morph.transform.transformers.BaseCompositeTransformer

components

Fields inherited from class net.sf.morph.transform.transformers.BaseTransformer

destinationClasses, log, sourceClasses

Fields inherited from interface net.sf.morph.transform.Transformer

TRANSFORMATION_TYPE_CONVERT, TRANSFORMATION_TYPE_COPY

Fields inherited from interface net.sf.morph.transform.Transformer

TRANSFORMATION_TYPE_CONVERT, TRANSFORMATION_TYPE_COPY

Fields inherited from interface net.sf.morph.transform.Transformer

TRANSFORMATION_TYPE_CONVERT, TRANSFORMATION_TYPE_COPY

Fields inherited from interface net.sf.morph.transform.Transformer

TRANSFORMATION_TYPE_CONVERT, TRANSFORMATION_TYPE_COPY

Fields inherited from interface net.sf.morph.transform.Transformer

TRANSFORMATION_TYPE_CONVERT, TRANSFORMATION_TYPE_COPY

Constructor Summary

SimpleDelegatingTransformer()
Construct a new SimpleDelegatingTransformer.

SimpleDelegatingTransformer(Transformer[] components)
Construct a new SimpleDelegatingTransformer.

SimpleDelegatingTransformer(Transformer[] components, boolean appendDefaultComponents)
Construct a new SimpleDelegatingTransformer.

Method Summary

protected void	clearVisitedSourceToDestinationMapIfNecessary() If we have popped everybody off the stack, clear the cache.
java.lang.Object	clone()
protected java.lang.Object	convertImpl(java.lang.Class destinationType, java.lang.Object source, java.util.Locale locale) The implementation of the convert method, which may omit the invalid argument checks already performed by this base class.
protected void	copyImpl(java.lang.Object destination, java.lang.Object source, java.util.Locale locale, java.lang.Integer preferredTransformationType) Implementation of the copy method.
protected Transformer[]	createDefaultComponents() Create the default set of Transformer components.
protected java.lang.Object	createReusableSource(java.lang.Class destinationClass, java.lang.Object source) NodeCopier.createReusableSource(Class, Object)
protected void	decrementStackDepth() Decrement the depth of the nested copy stack.
protected java.lang.Object	getCachedResult(java.lang.Object source, java.lang.Class destinationType) Get the cached object in the process of being transformed
java.lang.Object[]	getComponents()
protected Copier	getCopier(java.lang.Class destinationClass, java.lang.Class sourceClass) Finds a Copier that is capable of transforming sourceClass to destinationClass.
protected java.lang.Class[]	getDestinationClassesImpl() Transformer.getDestinationClasses() implementation template method.
protected java.lang.Class[]	getSourceClassesImpl() Transformer.getSourceClasses() implementation template method.
net.sf.composite.specialize.Specializer	getSpecializer() Get the Specializer for this SDT.
protected Transformer	getTransformer(java.lang.Class destinationClass, java.lang.Class sourceClass) Finds a Transformer that is capable of transforming sourceClass to destinationClass.
protected Transformer	getTransformer(java.util.Map registry, java.lang.Class transformerType, java.lang.Class destinationClass, java.lang.Class sourceClass) Finds a transformer of type transformerType that is capable of transforming sourceClass to destinationClass.
Transformer[]	getTransformers() Get our components as a typesafe Transformer array.
protected java.util.Map	getVisitedSourceToDestinationMap() Gets a Map of all the nodes in the object graph that have been transformed so far by this transformer.
protected boolean	hasVisited(java.lang.Object source, java.lang.Class destinationType) Avoid recursion by checking whether we have already begun a conversion of the specified source object to the specified destination class.
protected boolean	hasVisitedDestination(java.lang.Object source, java.lang.Object destination) Avoid recursion by checking whether we have already begun a copy of the specified source object to the specified destination object.
protected void	incrementStackDepth() Increment the depth of the nested copy stack.
protected void	initializeImpl() Gives subclasses a chance to perform any computations needed to initialize the transformer.
protected boolean	isAutomaticallyHandlingNulls() Indicates whether null values will automatically be converted to null by this base class before even calling the subclass's BaseTransformer.convertImpl(Class, Object, Locale) method.
protected boolean	isImpreciseTransformationImpl(java.lang.Class destinationClass, java.lang.Class sourceClass) Implementation of isImpreciseTransformation
protected boolean	isPerformingLogging() Let the delegate do the logging
boolean	isPreferPreciseTransformers() Get the preferPreciseTransformers.
boolean	isSpecializable(java.lang.Class type)
protected boolean	isTransformableImpl(java.lang.Class destinationType, java.lang.Class sourceType) Determines if one of the delegate transformers is capable of performing the given transformation.
protected void	recordVisit(java.lang.Object source, java.lang.Class destinationType, java.lang.Object destination) Cache destination object for this source/destination class combination.
void	setComponents(java.lang.Object[] components)
void	setPreferPreciseTransformers(boolean preferPreciseTransformers) Set the preferPreciseTransformers.
void	setSpecializer(net.sf.composite.specialize.Specializer specializer) Set the Specializer for this SDT.
java.lang.Object	specialize(java.lang.Class compositeType)

Methods inherited from class net.sf.morph.transform.transformers.BaseCompositeTransformer

getComponentType, getComponentValidator, isNarrowingComponentArray, isWrappingRuntimeExceptions, setComponentValidator, setNestedTransformer, updateNestedTransformerComponents

Methods inherited from class net.sf.morph.transform.transformers.BaseTransformer

convert, convert, copy, copy, createDefaultReflector, createNewInstance, createNewInstanceImpl, equals, equals, equalsUnidirectionalTest, getDestinationClasses, getInstantiatingReflector, getLocale, getLog, getNestedTransformer, getReflector, getReflector, getSourceClasses, getTransformableCallCache, getTransformerName, initialize, isCachingIsTransformableCalls, isImpreciseTransformation, isInitialized, isTransformable, setCachingIsTransformableCalls, setDestinationClasses, setInitialized, setLog, setReflector, setSourceClasses, setTransformableCallCache, setTransformerName, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.morph.transform.ExplicitTransformer

isTransformable

Methods inherited from interface net.sf.morph.transform.Transformer

getDestinationClasses, getSourceClasses

Methods inherited from interface net.sf.morph.transform.DecoratedCopier

copy

Methods inherited from interface net.sf.morph.transform.Copier

copy

Methods inherited from interface net.sf.morph.transform.Transformer

getDestinationClasses, getSourceClasses

Methods inherited from interface net.sf.morph.transform.Transformer

getDestinationClasses, getSourceClasses

Methods inherited from interface net.sf.morph.transform.ExplicitTransformer

isTransformable

Methods inherited from interface net.sf.morph.transform.DecoratedConverter

convert, equals, equals

Methods inherited from interface net.sf.morph.transform.Converter

convert

Methods inherited from interface net.sf.morph.transform.Transformer

getDestinationClasses, getSourceClasses

Methods inherited from interface net.sf.morph.transform.Transformer

getDestinationClasses, getSourceClasses

Methods inherited from interface net.sf.morph.transform.ExplicitTransformer

isTransformable

Methods inherited from interface net.sf.morph.transform.ImpreciseTransformer

isImpreciseTransformation

Constructor Detail

SimpleDelegatingTransformer

public SimpleDelegatingTransformer()

Construct a new SimpleDelegatingTransformer.

SimpleDelegatingTransformer

public SimpleDelegatingTransformer(Transformer[] components)

Construct a new SimpleDelegatingTransformer.

Parameters:

components -

SimpleDelegatingTransformer

public SimpleDelegatingTransformer(Transformer[] components,
                                   boolean appendDefaultComponents)

Construct a new SimpleDelegatingTransformer.

Parameters:

components -

appendDefaultComponents -

Method Detail

createDefaultComponents

protected Transformer[] createDefaultComponents()

Create the default set of Transformer components.

Returns:

Transformer[]

initializeImpl

protected void initializeImpl()
                       throws java.lang.Exception

Gives subclasses a chance to perform any computations needed to initialize the transformer.

Overrides:

initializeImpl in class BaseCompositeTransformer

Throws:

java.lang.Exception

See Also:

BaseCompositeTransformer.initializeImpl()

isTransformableImpl

protected boolean isTransformableImpl(java.lang.Class destinationType,
                                      java.lang.Class sourceType)
                               throws java.lang.Exception

Determines if one of the delegate transformers is capable of performing the given transformation. This method is necessary because otherwise the delegating transformer would be too eager in what it says it can convert. For example, if a delegate transformer was capable of transforming A to B and another delegate was capable of transforming C to D, this transformer would incorrectly state that transforming A to D and C to B was possible even though they are not.

Overrides:

isTransformableImpl in class BaseTransformer

Parameters:

destinationType - the destination type to test

sourceType - the source type to test

Returns:

whether the destination type is transformable to the source type

Throws:

TransformationException - if it could not be determined if sourceType is transformable into destinationType

java.lang.Exception

isImpreciseTransformationImpl

protected boolean isImpreciseTransformationImpl(java.lang.Class destinationClass,
                                                java.lang.Class sourceClass)

Implementation of isImpreciseTransformation

Overrides:

isImpreciseTransformationImpl in class BaseTransformer

Returns:

boolean

getSourceClassesImpl

protected java.lang.Class[] getSourceClassesImpl()
                                          throws java.lang.Exception

Transformer.getSourceClasses() implementation template method.

Specified by:

getSourceClassesImpl in class BaseTransformer

Returns:

Class[]

Throws:

java.lang.Exception

See Also:

BaseTransformer.getSourceClassesImpl()

getDestinationClassesImpl

protected java.lang.Class[] getDestinationClassesImpl()
                                               throws java.lang.Exception

Transformer.getDestinationClasses() implementation template method.

Specified by:

getDestinationClassesImpl in class BaseTransformer

Returns:

Class[]

Throws:

java.lang.Exception

See Also:

BaseTransformer.getDestinationClassesImpl()

copyImpl

protected void copyImpl(java.lang.Object destination,
                        java.lang.Object source,
                        java.util.Locale locale,
                        java.lang.Integer preferredTransformationType)
                 throws java.lang.Exception

Implementation of the copy method. By default, this method throws UnsupportedOperationException.

Overrides:

copyImpl in class BaseTransformer

Throws:

java.lang.Exception

See Also:

BaseTransformer.copyImpl(java.lang.Object, java.lang.Object, java.util.Locale, java.lang.Integer)

convertImpl

protected java.lang.Object convertImpl(java.lang.Class destinationType,
                                       java.lang.Object source,
                                       java.util.Locale locale)
                                throws java.lang.Exception

The implementation of the convert method, which may omit the invalid argument checks already performed by this base class. By default, this method creates a new instance of the destinationClass and copies information from the source to the destination. This implementation should be fine as-is for Copiers, but Converters will need to implement this method since they will not be implementing the copy method.

Overrides:

convertImpl in class BaseTransformer

locale - the locale in which the conversion should take place. for converters that are not locale-aware, the local argument can simply be ignored

Throws:

java.lang.Exception

See Also:

BaseTransformer.convertImpl(java.lang.Class, java.lang.Object, java.util.Locale)

incrementStackDepth

protected void incrementStackDepth()

Increment the depth of the nested copy stack.

decrementStackDepth

protected void decrementStackDepth()

Decrement the depth of the nested copy stack.

clearVisitedSourceToDestinationMapIfNecessary

protected void clearVisitedSourceToDestinationMapIfNecessary()

If we have popped everybody off the stack, clear the cache.

recordVisit

protected void recordVisit(java.lang.Object source,
                           java.lang.Class destinationType,
                           java.lang.Object destination)

Cache destination object for this source/destination class combination.

Parameters:

source -

destinationType -

destination -

hasVisited

protected boolean hasVisited(java.lang.Object source,
                             java.lang.Class destinationType)

Avoid recursion by checking whether we have already begun a conversion of the specified source object to the specified destination class.

Parameters:

source -

destinationType -

Returns:

boolean

hasVisitedDestination

protected boolean hasVisitedDestination(java.lang.Object source,
                                        java.lang.Object destination)

Avoid recursion by checking whether we have already begun a copy of the specified source object to the specified destination object.

Parameters:

source -

destination -

Returns:

boolean

getCachedResult

protected java.lang.Object getCachedResult(java.lang.Object source,
                                           java.lang.Class destinationType)

Get the cached object in the process of being transformed

Parameters:

source -

destinationType -

Returns:

specialize

public java.lang.Object specialize(java.lang.Class compositeType)

Specified by:

specialize in interface net.sf.composite.SpecializableComposite

See Also:

SpecializableComposite.specialize(java.lang.Class)

isSpecializable

public boolean isSpecializable(java.lang.Class type)
                        throws net.sf.composite.CompositeException

Specified by:

isSpecializable in interface net.sf.composite.SpecializableComposite

Throws:

net.sf.composite.CompositeException

See Also:

SpecializableComposite.isSpecializable(java.lang.Class)

getTransformer

protected Transformer getTransformer(java.util.Map registry,
                                     java.lang.Class transformerType,
                                     java.lang.Class destinationClass,
                                     java.lang.Class sourceClass)

Finds a transformer of type transformerType that is capable of transforming sourceClass to destinationClass. Caches results in the registry.

Parameters:

registry - a cache that remembers which transformers can be used for which transformations

transformerType - the type of the returned transformer

destinationClass - the destinationClass of the transformation

sourceClass - the sourceClass of the transformation

Returns:

the transformer of the requested type capable of performing the requested transformation

Throws:

TransformationException - if no suitable transformer could be found

getCopier

protected Copier getCopier(java.lang.Class destinationClass,
                           java.lang.Class sourceClass)

Finds a Copier that is capable of transforming sourceClass to destinationClass.

Parameters:

destinationClass - the destinationClass of the transformation

sourceClass - the sourceClass of the transformation

Returns:

the transformer of the requested type capable of performing the requested transformation

Throws:

TransformationException - if no suitable copier could be found

getTransformer

protected Transformer getTransformer(java.lang.Class destinationClass,
                                     java.lang.Class sourceClass)

Finds a Transformer that is capable of transforming sourceClass to destinationClass.

Parameters:

destinationClass - the destinationClass of the transformation

sourceClass - the sourceClass of the transformation

Returns:

the transformer of the requested type capable of performing the requested transformation

Throws:

TransformationException - if no suitable transformer could be found

getTransformers

public Transformer[] getTransformers()

Get our components as a typesafe Transformer array.

Returns:

Transformer[]

getComponents

public java.lang.Object[] getComponents()

Description copied from class: BaseCompositeTransformer

Specified by:

getComponents in interface net.sf.composite.SimpleComposite

Overrides:

getComponents in class BaseCompositeTransformer

See Also:

SimpleComposite.getComponents()

setComponents

public void setComponents(java.lang.Object[] components)

Description copied from class: BaseCompositeTransformer

Specified by:

setComponents in interface net.sf.composite.SimpleComposite

Overrides:

setComponents in class BaseCompositeTransformer

See Also:

SimpleComposite.setComponents(java.lang.Object[])

isPerformingLogging

protected boolean isPerformingLogging()

Let the delegate do the logging

Overrides:

isPerformingLogging in class BaseTransformer

Returns:

boolean

isAutomaticallyHandlingNulls

protected boolean isAutomaticallyHandlingNulls()

Indicates whether null values will automatically be converted to null by this base class before even calling the subclass's BaseTransformer.convertImpl(Class, Object, Locale) method. Subclasses which depend on this behavior (which is all subclasses, by default) should include null as one of their source and destination classes so that the actual behavior of the transformer is consistent with the values that are returned by the BaseTransformer.isTransformable(Class, Class) method. The conversions will happen automatically even if the source and destination classes don't contain null, but for the sake of consistency the nulls should be included.

Overrides:

isAutomaticallyHandlingNulls in class BaseTransformer

Returns:

whether null values will automatically be converted to null by this base class before even calling the subclass's BaseTransformer.convertImpl(Class, Object, Locale) method

See Also:

BaseTransformer.isAutomaticallyHandlingNulls()

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Overrides:

clone in class BaseTransformer

Throws:

java.lang.CloneNotSupportedException

See Also:

BaseTransformer.clone()

getVisitedSourceToDestinationMap

protected java.util.Map getVisitedSourceToDestinationMap()

Gets a Map of all the nodes in the object graph that have been transformed so far by this transformer. The keys in the Map are the visited source nodes, and the values are the converted representation of the node.

Returns:

a Map of all the nodes in the object graph that have been transformed so far by this transformer

getSpecializer

public net.sf.composite.specialize.Specializer getSpecializer()

Get the Specializer for this SDT.

Returns:

Specializer

setSpecializer

public void setSpecializer(net.sf.composite.specialize.Specializer specializer)

Set the Specializer for this SDT.

Parameters:

specializer -

createReusableSource

protected java.lang.Object createReusableSource(java.lang.Class destinationClass,
                                                java.lang.Object source)

NodeCopier.createReusableSource(Class, Object)

Overrides:

createReusableSource in class BaseTransformer

Returns:

See Also:

BaseTransformer.createReusableSource(java.lang.Class, java.lang.Object)

isPreferPreciseTransformers

public boolean isPreferPreciseTransformers()

Get the preferPreciseTransformers.

Returns:

boolean

setPreferPreciseTransformers

public void setPreferPreciseTransformers(boolean preferPreciseTransformers)

Set the preferPreciseTransformers. Default false.

Parameters:

preferPreciseTransformers - the boolean to set