001    // Copyright 2007 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.annotations.definition;
016    
017    import java.lang.annotation.Documented;
018    import java.lang.annotation.ElementType;
019    import java.lang.annotation.Retention;
020    import java.lang.annotation.RetentionPolicy;
021    import java.lang.annotation.Target;
022    
023    /**
024     * Marks a method in an annotated module as configuration point.
025     * The return type of the method defines the configuration type. 
026     * The method is used as factory method for the construction of the configuration.
027     * It can return null if no initial contribution is to be provided. 
028     *  
029     * @author Achim Huegen
030     */
031    @Documented
032    @Retention(value = RetentionPolicy.RUNTIME)
033    @Target(value = ElementType.METHOD)
034    public @interface Configuration {
035        String id();
036    }