001    // Copyright 2010 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.tapestry5.services.meta;
016    
017    import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
018    import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2;
019    
020    /**
021     * Service that makes it easy to identify a class annotation and use its presence, or the value of an attribute,
022     * to set a meta-data key. The configuration map class annotation types to corresponding extractors who will be invoked
023     * when the annotation is present. Most commonly, a {@link FixedExtractor} is used to set a fixed value to a fixed key,
024     * triggered by the presence of the corresponding annotation.
025     *
026     * @since 5.2.0
027     */
028    @UsesMappedConfiguration(key = Class.class, value = MetaDataExtractor.class)
029    public interface MetaWorker
030    {
031        /**
032         * Returns the worker that performs transformations (in 5.2, MetaWorker implemented ComponentClassTransformWorker).
033         *
034         * @return worker that implements the meta data analysis
035         */
036        ComponentClassTransformWorker2 getWorker();
037    }