Module org.eclipse.persistence.core
Package org.eclipse.persistence.internal.indirection

Class IndirectionPolicy

java.lang.Object
org.eclipse.persistence.internal.indirection.IndirectionPolicy
All Implemented Interfaces:
Serializable, Cloneable
Direct Known Subclasses:
BasicIndirectionPolicy, NoIndirectionPolicy, TransparentIndirectionPolicy
public abstract class IndirectionPolicy extends Object implements Cloneable, Serializable

Purpose

:

An IndirectionPolicy acts as a 'rules' holder that determines the behavior of a ForeignReferenceMapping (or TransformationMapping) with respect to indirection, or lack thereof.

Description

:

IndirectionPolicy is an abstract class that defines the protocol to be implemented by subclasses so that the assorted DatabaseMappings can use an assortment of indirection policies:

  • no indirection policy (read everything from database)
  • basic indirection policy (use ValueHolders)
  • transparent indirection policy (collections only)
  • proxy indirection policy (transparent 1:1 indirection using JDK 1.3's Proxy)

Responsibilities

:
  • instantiate the various IndirectionPolicies
Since:
TOPLink/Java 2.5
See Also:

  • Field Details

  • Constructor Details

    • IndirectionPolicy

      protected IndirectionPolicy()
      INTERNAL: Construct a new indirection policy.

  • Method Details

    • backupCloneAttribute

      public Object backupCloneAttribute(Object attributeValue, Object clone, Object backup, UnitOfWorkImpl unitOfWork)
      INTERNAL: Return a backup clone of the attribute.

    • buildCascadeQuery

      protected ReadObjectQuery buildCascadeQuery(MergeManager mergeManager)
      INTERNAL Return true if the refresh should refresh on this mapping or not.

    • buildIndirectObject

      public abstract Object buildIndirectObject(ValueHolderInterface valueHolder)
      INTERNAL: This method can be used when an Indirection Object is required to be built from a provided ValueHolderInterface object. This may be used for custom value holder types. Certain policies like the TransparentIndirectionPolicy may wrap the valueholder in another object.

    • clone

      public Object clone()
      INTERNAL: Clones itself.
      Overrides:
      clone in class Object

    • cloneAttribute

      public abstract Object cloneAttribute(Object attributeValue, Object original, CacheKey cacheKey, Object clone, Integer refreshCascade, AbstractSession cloningSession, boolean buildDirectlyFromRow)
      INTERNAL: Return a clone of the attribute.
      Parameters:
      buildDirectlyFromRow - indicates that we are building the clone directly from a row as opposed to building the original from the row, putting it in the shared cache, and then cloning the original.

    • extractPrimaryKeyForReferenceObject

      public Object extractPrimaryKeyForReferenceObject(Object referenceObject, AbstractSession session)
      INTERNAL: Return the primary key for the reference object (i.e. the object object referenced by domainObject and specified by mapping). This key will be used by a RemoteValueHolder.

    • extractReferenceRow

      public abstract AbstractRecord extractReferenceRow(Object referenceObject)
      INTERNAL: Return the reference row for the reference object. This allows the new row to be built without instantiating the reference object. Return null if the object has already been instantiated.

    • fixObjectReferences

      public abstract void fixObjectReferences(Object object, Map<Object,ObjectDescriptor> objectDescriptors, Map<Object,Object> processedObjects, ObjectLevelReadQuery query, DistributedSession session)
      INTERNAL: An object has been serialized from the server to the client. Replace the transient attributes of the remote value holders with client-side objects.

    • getCollectionMapping

      protected CollectionMapping getCollectionMapping()
      INTERNAL: Reduce casting clutter....

    • getForeignReferenceMapping

      protected ForeignReferenceMapping getForeignReferenceMapping()
      INTERNAL: Reduce casting clutter....

    • getMapping

      public DatabaseMapping getMapping()
      INTERNAL: Return the database mapping that uses the indirection policy.

    • getOneToOneMapping

      protected ObjectReferenceMapping getOneToOneMapping()
      INTERNAL: Reduce casting clutter....

    • getOriginalIndirectionObject

      public abstract Object getOriginalIndirectionObject(Object unitOfWorkIndirectionObject, AbstractSession session)
      INTERNAL: Return the original indirection object for a unit of work indirection object.

    • getOriginalIndirectionObjectForMerge

      public Object getOriginalIndirectionObjectForMerge(Object unitOfWorkIndirectionObject, AbstractSession session)
      INTERNAL: Return the original indirection object for a unit of work indirection object.

    • getOriginalValueHolder

      public abstract Object getOriginalValueHolder(Object unitOfWorkIndirectionObject, AbstractSession session)
      INTERNAL: Return the original valueHolder object. Access to the underlying valueholder may be required when serializing the valueholder or converting the valueHolder to another type.

    • getRealAttributeValueFromObject

      public abstract Object getRealAttributeValueFromObject(Object object, Object attribute)
      INTERNAL: Return the "real" attribute value, as opposed to any wrapper. This will trigger the wrapper to instantiate the value.

    • instantiateObject

      public void instantiateObject(Object object, Object attribute)
      INTERNAL: Trigger the instantiation of the value.

    • getTransformationMapping

      protected AbstractTransformationMapping getTransformationMapping()
      INTERNAL: Reduce casting clutter....

    • getValueFromRemoteValueHolder

      public abstract Object getValueFromRemoteValueHolder(RemoteValueHolder<?> remoteValueHolder)
      INTERNAL: Extract and return the appropriate value from the specified remote value holder.

    • isAttributeValueFullyBuilt

      public boolean isAttributeValueFullyBuilt(Object attributeValue)
      INTERNAL: The method validateAttributeOfInstantiatedObject(Object attributeValue) fixes the value of the attributeValue in cases where it is null and indirection requires that it contain some specific data structure. Return whether this will happen. This method is used to help determine if indirection has been triggered
      See Also:

    • initialize

      public void initialize()
      INTERNAL: Initialize the indirection policy (Do nothing by default)

    • isWeavedObjectBasicIndirectionPolicy

      public boolean isWeavedObjectBasicIndirectionPolicy()
      INTERNAL:

    • iterateOnAttributeValue

      public void iterateOnAttributeValue(DescriptorIterator iterator, Object attributeValue)
      INTERNAL: Iterate over the specified attribute value, heeding the settings in the iterator.

    • mergeClientIntoServerValueHolder

      protected void mergeClientIntoServerValueHolder(RemoteValueHolder<?> serverValueHolder, MergeManager mergeManager)
      INTERNAL Replace the client value holder with the server value holder, after copying some of the settings from the client value holder.

    • mergeRemoteValueHolder

      public abstract void mergeRemoteValueHolder(Object clientSideDomainObject, Object serverSideDomainObject, MergeManager mergeManager)
      INTERNAL Replace the client value holder with the server value holder, after copying some of the settings from the client value holder.

    • nullValueFromRow

      public abstract Object nullValueFromRow()
      INTERNAL: Return the null value of the appropriate attribute. That is, the field from the database is NULL, return what should be placed in the object's attribute as a result.

    • objectIsInstantiated

      public abstract boolean objectIsInstantiated(Object object)
      INTERNAL: Return whether the specified object is instantiated.

    • objectIsEasilyInstantiated

      public abstract boolean objectIsEasilyInstantiated(Object object)
      INTERNAL: Return whether the specified object can be instantiated without database access.

    • objectIsInstantiatedOrChanged

      public boolean objectIsInstantiatedOrChanged(Object object)
      INTERNAL: Return whether the specified object is instantiated, or if it has changes.

    • setMapping

      public void setMapping(DatabaseMapping mapping)
      INTERNAL: set the database mapping that uses the indirection policy.

    • setRealAttributeValueInObject

      public void setRealAttributeValueInObject(Object target, Object attributeValue)
      INTERNAL: Set the value of the appropriate attribute of target to attributeValue. In this case, simply place the value inside the target.

    • setRealAttributeValueInObject

      public void setRealAttributeValueInObject(Object target, Object attributeValue, boolean allowChangeTracking)
      INTERNAL: Same functionality as setRealAttributeValueInObject(Object target, Object attributeValue) but allows overridden behavior for IndirectionPolicies that track changes

    • setSourceObject

      public void setSourceObject(Object sourceObject, Object attributeValue)
      INTERNAL: set the source object into QueryBasedValueHolder. Used only by transparent indirection.

    • setUseLazyInstantiation

      public void setUseLazyInstantiation(Boolean useLazyInstantiation)
      ADVANCED: This method will only change the behavior of TransparentIndirectionPolicy. IndirectList and IndirectSet can be configured not to instantiate the list from the database when you add and remove from them. IndirectList defaults to this behavior. When Set to true, the collection associated with this TransparentIndirection will be setup so as not to instantiate for adds and removes. The weakness of this setting for an IndirectSet is that when the set is not instantiated, if a duplicate element is added, it will not be detected until commit time.

    • shouldUseLazyInstantiation

      public Boolean shouldUseLazyInstantiation()
      ADVANCED: Returns false unless this is a transparent indirection policy IndirectList and IndirectSet can be configured not to instantiate the list from the database when you add and remove from them. IndirectList defaults to this behavior. When Set to true, the collection associated with this TransparentIndirection will be setup so as not to instantiate for adds and removes. The weakness of this setting for an IndirectSet is that when the set is not instantiated, if a duplicate element is added, it will not be detected until commit time.

    • reset

      public void reset(Object target)
      Reset the wrapper used to store the value. This is only required if a wrapper is used.

    • usesIndirection

      public boolean usesIndirection()
      INTERNAL: Return whether the indirection policy actually uses indirection. The default is true.

    • usesTransparentIndirection

      public boolean usesTransparentIndirection()
      INTERNAL: Return whether the indirection policy uses transparent indirection. The default is false.

    • validateAttributeOfInstantiatedObject

      public Object validateAttributeOfInstantiatedObject(Object attributeValue) throws DescriptorException
      INTERNAL: Verify that the value of the attribute within an instantiated object is of the appropriate type for the indirection policy. If it is incorrect, throw an exception. If the value is null return a new indirection object to be used for the attribute.
      Throws:
      DescriptorException

    • validateContainerPolicy

      public void validateContainerPolicy(IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that the container policy is compatible with the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateDeclaredAttributeType

      public void validateDeclaredAttributeType(Class<?> attributeType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that attributeType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateDeclaredAttributeTypeForCollection

      public void validateDeclaredAttributeTypeForCollection(Class<?> attributeType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that attributeType is an appropriate collection type for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateGetMethodReturnType

      public void validateGetMethodReturnType(Class<?> returnType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that getter returnType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateGetMethodReturnTypeForCollection

      public void validateGetMethodReturnTypeForCollection(Class<?> returnType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that getter returnType is an appropriate collection type for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateSetMethodParameterType

      public void validateSetMethodParameterType(Class<?> parameterType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that setter parameterType is correct for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • validateSetMethodParameterTypeForCollection

      public void validateSetMethodParameterTypeForCollection(Class<?> parameterType, IntegrityChecker checker) throws DescriptorException
      INTERNAL: Verify that setter parameterType is an appropriate collection type for the indirection policy. If it is incorrect, add an exception to the integrity checker.
      Throws:
      DescriptorException

    • valueFromBatchQuery

      public abstract Object valueFromBatchQuery(ReadQuery batchQuery, AbstractRecord row, ObjectLevelReadQuery originalQuery, CacheKey parentCacheKey)
      INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the batchQuery.

    • valueFromMethod

      public abstract Object valueFromMethod(Object object, AbstractRecord row, AbstractSession session)
      INTERNAL: Return the value to be stored in the object's attribute. This value is determined by invoking the appropriate method on the object and passing it the row and session.

    • valueFromQuery

      public abstract Object valueFromQuery(ReadQuery query, AbstractRecord row, Object sourceObject, AbstractSession session)
      INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the query.

    • valueFromQuery

      public abstract Object valueFromQuery(ReadQuery query, AbstractRecord row, AbstractSession session)
      INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the query.

    • valueFromRow

      public abstract Object valueFromRow(Object object)
      INTERNAL: Return the value to be stored in the object's attribute. This value is determined by the row.