001/* 
002    Licensed to the Apache Software Foundation (ASF) under one
003    or more contributor license agreements.  See the NOTICE file
004    distributed with this work for additional information
005    regarding copyright ownership.  The ASF licenses this file
006    to you under the Apache License, Version 2.0 (the
007    "License"); you may not use this file except in compliance
008    with the License.  You may obtain a copy of the License at
009
010       http://www.apache.org/licenses/LICENSE-2.0
011
012    Unless required by applicable law or agreed to in writing,
013    software distributed under the License is distributed on an
014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015    KIND, either express or implied.  See the License for the
016    specific language governing permissions and limitations
017    under the License.  
018 */
019package org.apache.wiki;
020
021
022/**
023 *  A watchdog needs something to watch.  If you wish to be watched, implement this interface.
024 */
025public interface Watchable {
026
027    /**
028     *  This is a callback which is called whenever your expected completion time is exceeded.  The current state of the
029     *  stack is available.
030     *
031     *  @param state The state in which your Watchable is currently.
032     */
033    void timeoutExceeded( String state );
034
035    /**
036     *  Returns a human-readable name of this Watchable.  Used in logging.
037     *
038     *  @return The name of the Watchable.
039     */
040    String getName();
041
042    /**
043     *  Returns <code>true</code>, if this Watchable is still alive and can be watched; otherwise <code>false</code>. 
044     *  For example, a stopped Thread is not very interesting to watch.
045     *
046     *  @return the result
047     */
048    boolean isAlive();
049
050}