001    // Copyright 2007, 2008 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.internal.services;
016    
017    import org.apache.tapestry5.annotations.Path;
018    import org.apache.tapestry5.ioc.ObjectLocator;
019    import org.apache.tapestry5.ioc.Resource;
020    import org.apache.tapestry5.ioc.services.SymbolSource;
021    import org.apache.tapestry5.model.MutableComponentModel;
022    import org.apache.tapestry5.services.AssetSource;
023    import org.apache.tapestry5.services.ClassTransformation;
024    import org.apache.tapestry5.services.InjectionProvider;
025    
026    import static java.lang.String.format;
027    
028    /**
029     * Performs injection of assets, based on the presence of the {@link Path} annotation. This is more useful than the
030     * general {@link AssetObjectProvider}, becase relative assets are supported.
031     */
032    public class AssetInjectionProvider implements InjectionProvider
033    {
034        private final SymbolSource symbolSource;
035    
036        private final AssetSource assetSource;
037    
038        public AssetInjectionProvider(SymbolSource symbolSource, AssetSource assetSource)
039        {
040            this.symbolSource = symbolSource;
041            this.assetSource = assetSource;
042        }
043    
044        public boolean provideInjection(String fieldName, Class fieldType, ObjectLocator locator,
045                                        ClassTransformation transformation, MutableComponentModel componentModel)
046        {
047            Path path = transformation.getFieldAnnotation(fieldName, Path.class);
048    
049            if (path == null) return false;
050    
051            String expanded = symbolSource.expandSymbols(path.value());
052    
053            String sourceFieldName = transformation.addInjectedField(AssetSource.class, "assetSource", assetSource);
054    
055            String baseResourceFieldName = transformation.addInjectedField(Resource.class, "baseResource",
056                                                                           componentModel.getBaseResource());
057    
058            String resourcesFieldName = transformation.getResourcesFieldName();
059    
060            String statement = format("%s = (%s) %s.getAsset(%s, \"%s\", %s.getLocale());", fieldName, fieldType.getName(),
061                                      sourceFieldName, baseResourceFieldName, expanded, resourcesFieldName);
062    
063            transformation.extendConstructor(statement);
064    
065            transformation.makeReadOnly(fieldName);
066    
067            return true;
068        }
069    
070    }