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
015package org.apache.tapestry5.services.meta;
016
017import java.lang.annotation.Annotation;
018
019import org.apache.tapestry5.ioc.internal.util.InternalUtils;
020import org.apache.tapestry5.model.MutableComponentModel;
021
022/**
023 * Implementation of {@link MetaDataExtractor} that is used to set a fixed
024 * value for a fixed meta-data key, when a given annotation is present.
025 * 
026 * @since 5.2.0
027 */
028public class FixedExtractor<T extends Annotation> implements MetaDataExtractor<T>
029{
030    private final String key;
031
032    private final String value;
033
034    /** Defaults the value to "true". */
035    public FixedExtractor(String key)
036    {
037        this(key, "true");
038    }
039
040    public FixedExtractor(String key, String value)
041    {
042        assert InternalUtils.isNonBlank(key);
043        this.key = key;
044        assert InternalUtils.isNonBlank(value);
045        this.value = value;
046    }
047
048    public void extractMetaData(MutableComponentModel model, T annotation)
049    {
050        model.setMeta(key, value);
051    }
052
053}