oracle.ifs.fdk.impl.ah

Class ChainedAttributeHandler

java.lang.Object

oracle.ifs.fdk.impl.ah.ChainedAttributeHandler

All Implemented Interfaces:

AttributeHandler

public class ChainedAttributeHandler
extends Object
implements AttributeHandler

This special attribute handler allows chaining of multiple attribute handlers so that the final attribute from a tree of objects can be read or set.

Constructor Summary

Constructors

Constructor and Description
ChainedAttributeHandler(String reposAttrName, AttributeHandler handler) Constructor.

Method Summary

Modifier and Type	Method and Description
boolean	canHandle(AttributeHandlerContext context) Returns true if this handler can handle the attribute request on the given object instance.
boolean	canUpdate(AttributeHandlerContext context) Returns true if this handler can update the attribute, false if the attribute is not updateable.
Object	getValue(AttributeHandlerContext context) Returns the value of an attribute.
AttributeUpdater	setValue(AttributeHandlerContext context, Object value) Updates the attribute with the given value.

Methods inherited from class java.lang.Object

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

Constructor Detail

ChainedAttributeHandler

public ChainedAttributeHandler(String reposAttrName,
                               AttributeHandler handler)

Constructor.

Parameters:

reposAttrName - The attribute to pull from the underlying handler.

handler - The underlying attribute handler.

Method Detail

canHandle

public boolean canHandle(AttributeHandlerContext context)
                  throws FdkException,
                         IfsException

Description copied from interface: AttributeHandler

Returns true if this handler can handle the attribute request on the given object instance. The necessary information to determine which attribute is requested and what the underlying repository object is will be packaged in the context.

Specified by:

canHandle in interface AttributeHandler

Parameters:

context - The context when this handler is called.

Throws:

FdkException - If a framework error occurs.

IfsException - If a repository exception occurs.

canUpdate

public boolean canUpdate(AttributeHandlerContext context)
                  throws FdkException,
                         IfsException

Description copied from interface: AttributeHandler

Returns true if this handler can update the attribute, false if the attribute is not updateable. The necessary information to determine which attribute is requested and what the underlying repository object is will be packaged in the context.

Specified by:

canUpdate in interface AttributeHandler

Parameters:

context - The context when this handler is called.

Throws:

FdkException - If a framework error occurs.

IfsException - If a repository exception occurs.

getValue

public Object getValue(AttributeHandlerContext context)
                throws FdkException,
                       IfsException

Description copied from interface: AttributeHandler

Returns the value of an attribute. This method must throw a RuntimeException if canHandle() returns false and this method is still being called.

Note that implementations which handle read-only attributes should subclass ReadOnlyAttributeHandler for convenience as they would need to provide the read side methods only.

Specified by:

getValue in interface AttributeHandler

Parameters:

context - The context when this handler is called.

Throws:

FdkException - If a framework error occurs.

IfsException - If a repository exception occurs.

setValue

public AttributeUpdater setValue(AttributeHandlerContext context,
                                 Object value)
                          throws FdkException,
                                 IfsException

Description copied from interface: AttributeHandler

Updates the attribute with the given value. This method must throw a RuntimeException if canUpdate() returns false and this method is still being called.

An implementation of this method has two choices:

1. If the update would result in a simple repository attribute update it must return an AttributeUpdater object filled in with the repositoy object to update, the name of the attribute and the value of the attribute (which may be a derived value from the value passed in). The driving code that invokes it will then do the actual update in an optimized way.
2. The implementation may decide under special circumstances that it needs to do the update itself (because the logic is too complicated for the driving code to implement and it is a special case). In that case the return value must be null in order to notify the caller the update was executed.

Specified by:

setValue in interface AttributeHandler

Parameters:

context - The context when this handler is called.

value - The value to set the attribute to.

Throws:

FdkException - If a framework error occurs.

IfsException - If a repository exception occurs.