org.apache.clerezza.WatchableGraph Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied. See the License for the specific
* language governing permissions and limitations under the License.
*/
package org.apache.clerezza;
import org.apache.clerezza.event.FilterTriple;
import org.apache.clerezza.event.GraphListener;
/**
* An extension to the Graph interface that allows to add throws events
* on modifications.
*
* @author reto
*/
public interface WatchableGraph extends Graph {
/**
* Adds the specified GraphListener to the graph. This listener
* will be notified, when the graph is modified and the Triple
* that was part of the modifiaction matched the specified
* FilterTriple. The notification will be passed to the
* listener after the specified delay time (in milli-seconds) has passed.
* If more matching events occur during the delay period, then they are
* passed all together at the end of the delay period. If the the listener
* unregisters or the platform is stopped within the period then the already
* occurred events may not be delivered.
*
* All implementations support this method, immutable implementations will
* typically provide an empty implementation, they shall not throw an
* exception.
*
* Implementation of which the triples change over time without add- and
* remove-methods being called (e.g. implementation dynamically generating
* their triples on invocation of the filer-method) may choose not to, or
* only partially propagate their changes to the listener. They should
* describe the behavior in the documentation of the class.
*
* Implementations should keep weak references the listeners, so that the
* listener can be garbage collected if its no longer referenced by another
* object.
*
* If delay is 0 notification will happen synchroneously.
*
* @param listener The listener that will be notified
* @param filter The triple filter with which triples are tested,
* that were part of the modification.
* @param delay The time period afer which the listener will be notified in milliseconds.
*/
public void addGraphListener(GraphListener listener, FilterTriple filter,
long delay);
/**
* Adds the specified GraphListener to the graph. This listener
* will be notified, when the graph is modified and the Triple
* that was part of the modifiaction matched the specified
* FilterTriple. The notification will be passed without delay.
*
* Same as addGraphListener(listener, filter, 0).
*
* @param listener The listener that will be notified
* @param filter The triple filter with which triples are tested,
* that were part of the modification.
*/
public void addGraphListener(GraphListener listener, FilterTriple filter);
/**
* Removes the specified GraphListener from the graph. This
* listener will no longer be notified, when the graph is modified.
*
* @param listener The listener to be removed.
*/
public void removeGraphListener(GraphListener listener);
}