org.datamanager.kernel
Class AbstractEventConstraint

java.lang.Object
  |
  +--org.datamanager.kernel.AbstractEventConstraint

All Implemented Interfaces:

Constraint, EntityValue, EventConstraint, Serializable

Direct Known Subclasses:

AndEventConstraint, EventContainsEntityConstraint, EventTypeIsConstraint, NotEventConstraint, OrEventConstraint

public abstract class AbstractEventConstraint

extends Object

implements EventConstraint

This class is an abstract EventConstraint class. It implements the EventConstraint interface located in org.datamanager.constraint, and provides a public describes() method, which is exactly the same as the public abstract accepts() method in EventConstriant. Every EventConstraint should ideally extend this class instead of implementing EventConstraint themselves. By doing so the constraint will gain extra power while working with Entities in the kernel. For example, a when a constraint is working on an Entity, calling methods such as getValue() and getAttributes(), it should not cause DataManagerEvents to be fired. If the constriant is a subclass of AbstractConstraint then no events will be fired, otherwise events will. If a constraint has already been written to implement EventConstraint it can easily be modified to use this class instead simply by changing implements EventConstraint to extends AbstractEventConstraint and renaming the accepts() method to describes().

Version:

$Revision: 1.9 $

Author:

Matthew Farrellee

See Also:

EntityConstraint, DataManagerEvent, Serialized Form

Field Summary

static String

DEBUG_ACCEPTS_MESSAGE

Fields inherited from interface org.datamanager.constraint.EventConstraint

NONE

Constructor Summary

AbstractEventConstraint()

Method Summary

boolean	accepts(DataManagerEvent event) The accepts() method required by the EventConstraint interface.
protected abstract boolean	describes(DataManagerEvent event) The method required by this class.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG_ACCEPTS_MESSAGE

public static final String DEBUG_ACCEPTS_MESSAGE

See Also:

Constant Field Values

Constructor Detail

AbstractEventConstraint

public AbstractEventConstraint()

Method Detail

accepts

public final boolean accepts(DataManagerEvent event)
                      throws DataManagerException

The accepts() method required by the EventConstraint interface. This class implements this method and makes it final, so no subclasses can override the work that is done by this class. Eventually this accepts() method will call the describes() method that should be implemented by subclasses.

Specified by:

accepts in interface EventConstraint

Parameters:

event - An event to check.

Returns:

Whether the event is acceptable or not.

DataManagerException

describes

protected abstract boolean describes(DataManagerEvent event)
                              throws DataManagerException

The method required by this class. This method has the exact same semantics as the interface EventConstraint's accepts() method.

Parameters:

event - An entity to check.

Returns:

Whether the event is acceptable or not.

DataManagerException