Package org.eclipse.persistence.internal.indirection

Class ProxyIndirectionPolicy

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable
    public class ProxyIndirectionPolicy
extends BasicIndirectionPolicy

    ProxyIndirectionPolicy

    Define the behavior for Proxy Indirection.

    Proxy Indirection uses the Proxy and InvocationHandler features of JDK 1.3 to provide "transparent indirection" for 1:1 relationships. In order to use Proxy Indirection:

    • The target class must implement at least one public interface
    • The attribute on the source class must be typed as that public interface
    In this policy, proxy objects are returned during object creation. When a message other than toString is called on the proxy the real object data is retrieved from the database.
    Since:
    TopLink 3.0
    Author:
    Rick Barkhouse
    See Also:
    ProxyIndirectionHandler, Serialized Form

    • Constructor Detail

      • ProxyIndirectionPolicy

        public ProxyIndirectionPolicy​(java.lang.Class[] targetInterfaces)

      • ProxyIndirectionPolicy

        public ProxyIndirectionPolicy()

    • Method Detail

      • reset

        public void reset​(java.lang.Object target)
        Reset the wrapper used to store the value.
        Overrides:
        reset in class BasicIndirectionPolicy

      • hasTargetInterfaces

        public boolean hasTargetInterfaces()
        INTERNAL: Return if targetInterfaces is not empty.

      • valueFromRow

        public java.lang.Object valueFromRow​(java.lang.Object object)
        INTERNAL: Return the value to be stored in the object's attribute. This will be a proxy object.
        Overrides:
        valueFromRow in class BasicIndirectionPolicy

      • valueFromMethod

        public java.lang.Object valueFromMethod​(java.lang.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.
        Overrides:
        valueFromMethod in class BasicIndirectionPolicy

      • objectIsInstantiated

        public boolean objectIsInstantiated​(java.lang.Object object)
        INTERNAL: Return whether the specified object is instantiated.
        Overrides:
        objectIsInstantiated in class BasicIndirectionPolicy

      • objectIsEasilyInstantiated

        public boolean objectIsEasilyInstantiated​(java.lang.Object object)
        INTERNAL: Return whether the specified object can be instantiated without database access.
        Overrides:
        objectIsEasilyInstantiated in class BasicIndirectionPolicy

      • nullValueFromRow

        public java.lang.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.
        Overrides:
        nullValueFromRow in class BasicIndirectionPolicy

      • mergeRemoteValueHolder

        public void mergeRemoteValueHolder​(java.lang.Object clientSideDomainObject,
                                   java.lang.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.
        Overrides:
        mergeRemoteValueHolder in class BasicIndirectionPolicy

      • getRealAttributeValueFromObject

        public java.lang.Object getRealAttributeValueFromObject​(java.lang.Object obj,
                                                        java.lang.Object object)
        INTERNAL: Return the "real" attribute value, as opposed to any wrapper. This will trigger the wrapper to instantiate the value.
        Overrides:
        getRealAttributeValueFromObject in class BasicIndirectionPolicy

      • getValueFromProxy

        public static java.lang.Object getValueFromProxy​(java.lang.Object value)
        INTERNAL: Given a proxy object, trigger the indirection and return the actual object represented by the proxy.

      • setRealAttributeValueInObject

        public void setRealAttributeValueInObject​(java.lang.Object target,
                                          java.lang.Object attributeValue)
        INTERNAL: Set the "real" value of the attribute to attributeValue.
        Overrides:
        setRealAttributeValueInObject in class BasicIndirectionPolicy

      • fixObjectReferences

        public void fixObjectReferences​(java.lang.Object object,
                                java.util.Map objectDescriptors,
                                java.util.Map 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.
        Overrides:
        fixObjectReferences in class BasicIndirectionPolicy

      • extractReferenceRow

        public AbstractRecord extractReferenceRow​(java.lang.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.
        Overrides:
        extractReferenceRow in class BasicIndirectionPolicy

      • cloneAttribute

        public java.lang.Object cloneAttribute​(java.lang.Object attributeValue,
                                       java.lang.Object original,
                                       CacheKey cacheKey,
                                       java.lang.Object clone,
                                       java.lang.Integer refreshCascade,
                                       AbstractSession cloningSession,
                                       boolean buildDirectlyFromRow)
        INTERNAL: Return a clone of the attribute.
        Overrides:
        cloneAttribute in class BasicIndirectionPolicy
        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.

      • backupCloneAttribute

        public java.lang.Object backupCloneAttribute​(java.lang.Object attributeValue,
                                             java.lang.Object clone,
                                             java.lang.Object backup,
                                             UnitOfWorkImpl unitOfWork)
        INTERNAL: Return a backup clone of the attribute.
        Overrides:
        backupCloneAttribute in class BasicIndirectionPolicy

      • validateAttributeOfInstantiatedObject

        public java.lang.Object validateAttributeOfInstantiatedObject​(java.lang.Object attributeValue)
        INTERNAL: Verify that the value of the attribute within an instantiated object is of the appropriate type for the indirection policy. In this case, the attribute must non-null and implement some public interface.
        Overrides:
        validateAttributeOfInstantiatedObject in class BasicIndirectionPolicy

      • isAttributeValueFullyBuilt

        public boolean isAttributeValueFullyBuilt​(java.lang.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
        Overrides:
        isAttributeValueFullyBuilt in class BasicIndirectionPolicy
        Parameters:
        attributeValue -
        Returns:
        See Also:
        validateAttributeOfInstantiatedObject(java.lang.Object)

      • isValidType

        public boolean isValidType​(java.lang.Class attributeType)
        INTERNAL: Verify that a class type is valid to use for the proxy. The class must be one of the interfaces in targetInterfaces.