/**
* 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.waveprotocol.wave.model.adt;
/**
* Extension of a {@link MonotonicValue} that broadcasts events whenever
* the value changes.
*
*/
public interface ObservableMonotonicValue<C extends Comparable<C>> extends MonotonicValue<C> {
public interface Listener<C> {
/**
* Notifies this listener that the value has increased, or been removed
* (in which case the new value is null). In the latter case, the value
* is no longer usable.
*
* @param newValue new value
*/
void onSet(C oldValue, C newValue);
}
/**
* Adds a listener.
*
* @param l listener to add
*/
void addListener(Listener<? super C> l);
/**
* Removes a listener.
*
* @param l listener to remove
*/
void removeListener(Listener<? super C> l);
}