001    // Copyright 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.tapestry.annotations;
016    
017    import java.lang.reflect.Method;
018    
019    import org.apache.hivemind.Location;
020    import org.apache.hivemind.Resource;
021    import org.apache.tapestry.enhance.EnhancementOperation;
022    import org.apache.tapestry.spec.IComponentSpecification;
023    import org.apache.tapestry.spec.IPropertySpecification;
024    import org.apache.tapestry.spec.PropertySpecification;
025    
026    /**
027     * Looks for {@link org.apache.tapestry.annotations.InitialValue} annotations on methods that don't
028     * have a {@link org.apache.tapestry.annotations.Persist} annotation (that's handled by
029     * {@link org.apache.tapestry.annotations.PersistAnnotationWorker}); adds an
030     * {@link org.apache.tapestry.spec.IPropertySpecification} for the property, so that its initial
031     * value may be set.
032     * 
033     * @author Howard M. Lewis Ship
034     * @since 4.0
035     */
036    public class InitialValueAnnotationWorker implements SecondaryAnnotationWorker
037    {
038        /**
039         * Returns true if the method has the InitialValue annotation.
040         */
041        public boolean canEnhance(Method method)
042        {
043            return method.getAnnotation(InitialValue.class) != null;
044        }
045    
046        public void peformEnhancement(EnhancementOperation op, IComponentSpecification spec,
047                Method method, Resource classResource)
048        {
049            InitialValue iv = method.getAnnotation(InitialValue.class);
050    
051            if (iv == null)
052                return;
053    
054            if (method.getAnnotation(Persist.class) != null)
055                return;
056    
057            Location location = AnnotationUtils.buildLocationForAnnotation(method, iv, classResource);
058    
059            String propertyName = AnnotationUtils.getPropertyName(method);
060    
061            // Define a transient property
062    
063            IPropertySpecification pspec = new PropertySpecification();
064    
065            pspec.setName(propertyName);
066            pspec.setLocation(location);
067            pspec.setInitialValue(iv.value());
068    
069            spec.addPropertySpecification(pspec);
070        }
071    }