001    package org.apache.fulcrum.yaafi.framework.tls;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    /**
023     * Provides a service which can temporarily store
024     * thread-local data. This is useful in a multithreaded
025     * environment, such as a servlet or Tapestry application.
026     * ThreadLocalStorage acts like a map around thread local data.
027     *
028     * The code was pasted from the Hivemind container written by
029     * Howard Lewis Ship.
030     *
031     * @author <a href="mailto:siegfried.goeschl@it20one.at">Siegfried Goeschl</a>
032     */
033    
034    public interface ThreadLocalStorage
035    {
036        /**
037             * Returns the thread-local object for the given key, or null
038             * if no such object exists.
039             *
040             * @param key the key for the lookup
041             * @return the object
042             */
043            public Object get(String key);
044    
045            /**
046             * Stores the value object at the given key, overwriting
047             * any prior value that may have been stored at that key.
048             * Care should be taken in selecting keys to avoid
049             * naming conflicts; in general, prefixing a key with
050             * a module id is a good idea.
051             *
052             * @param key the key of the object to store
053             * @param value the value of the object to store
054             */
055            public void put(String key, Object value);
056    
057            /**
058             * Checks if the thread-local object for the given key exists
059             *
060             * @param key the key for the lookup
061             * @return true the object exists
062             */
063            public boolean containsKey(String key);
064    
065            /**
066             * Clears all keys.
067             */
068            public void clear();
069    }