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.schema.rules;
016    
017    import org.apache.hivemind.HiveMind;
018    import org.apache.hivemind.Location;
019    import org.apache.hivemind.internal.Module;
020    import org.apache.hivemind.schema.Translator;
021    
022    /**
023     * Used to translate a value into a reference to a HiveMind service within the registry.
024     * 
025     * @author Howard Lewis Ship
026     */
027    public class ServiceTranslator implements Translator
028    {
029        /**
030         * Returns null if the input is null or empty. Returns the service with the given name
031         * otherwise. Will log an error and return null if an exception is thrown. If the input value is
032         * not qualified, the contributing module's id is added as a prefix.
033         */
034        public Object translate(Module contributingModule, Class propertyType, String inputValue,
035                Location location)
036        {
037            if (HiveMind.isBlank(inputValue))
038                return null;
039    
040            return contributingModule.getService(inputValue, Object.class);
041        }
042    
043    }