001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind;
016    
017    /**
018     * Used to define an object that can provide a value for a substitution symbol
019     * (substitution symbol can appear in HiveMind module deployment descriptors).
020     *
021     * @author Howard Lewis Ship
022     */
023    
024    public interface SymbolSource
025    {
026            /**
027             * Returns the value for the symbol, if this source can provide one.
028             * Returns null if the source can not provide a value.
029             */
030            public String valueForSymbol(String name);
031    }