001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package org.apache.commons.pipeline.validation;
019    
020    import java.lang.annotation.ElementType;
021    import java.lang.annotation.Retention;
022    import java.lang.annotation.RetentionPolicy;
023    import java.lang.annotation.Target;
024    
025    import org.apache.commons.pipeline.Stage;
026    
027    /**
028     * This marker annotation indicates that the {@link Stage} produces the same type
029     * of object that is consumed (or any subtype thereof). This is used to allow
030     * correct resolution of stage compatibility between different parts of a
031     * pipeline when there are intervening generic pass-through stages such
032     * as loggers, which can consume any type of object and produce the
033     * same object unchanged.
034     *
035     * This annotation is used in lieu of the {@link Production} annotaion
036     * and overrides it if both are present.
037     *
038     *
039     */
040    @Target(ElementType.TYPE)
041    @Retention(RetentionPolicy.RUNTIME)
042    public @interface ProducesConsumed { }