001// Copyright 2007, 2008, 2010, 2011 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.internal.services;
016
017import org.apache.tapestry5.Asset;
018import org.apache.tapestry5.ComponentResources;
019import org.apache.tapestry5.annotations.Path;
020import org.apache.tapestry5.ioc.ObjectLocator;
021import org.apache.tapestry5.ioc.Resource;
022import org.apache.tapestry5.ioc.services.SymbolSource;
023import org.apache.tapestry5.model.MutableComponentModel;
024import org.apache.tapestry5.plastic.ComputedValue;
025import org.apache.tapestry5.plastic.InstanceContext;
026import org.apache.tapestry5.plastic.PlasticField;
027import org.apache.tapestry5.services.AssetSource;
028import org.apache.tapestry5.services.transform.InjectionProvider2;
029
030import java.util.Locale;
031
032/**
033 * Performs injection of assets, based on the presence of the {@link Path} annotation. This is more
034 * useful than the
035 * general {@link AssetObjectProvider}, because relative assets are supported.
036 */
037public class AssetInjectionProvider implements InjectionProvider2
038{
039    private final SymbolSource symbolSource;
040
041    private final AssetSource assetSource;
042
043    public AssetInjectionProvider(SymbolSource symbolSource, AssetSource assetSource)
044    {
045        this.symbolSource = symbolSource;
046        this.assetSource = assetSource;
047    }
048
049    public boolean provideInjection(PlasticField field, ObjectLocator locator, MutableComponentModel componentModel)
050    {
051        Path path = field.getAnnotation(Path.class);
052
053        if (path == null)
054        {
055            return false;
056        }
057
058        final String expanded = symbolSource.expandSymbols(path.value());
059
060        final Resource baseResource = componentModel.getBaseResource();
061
062        ComputedValue<Asset> computedAsset = new ComputedValue<Asset>()
063        {
064            public Asset get(InstanceContext context)
065            {
066                ComponentResources resources = context.get(ComponentResources.class);
067
068                Locale locale = resources.getLocale();
069
070                return assetSource.getAsset(baseResource, expanded, locale);
071            }
072        };
073
074        field.injectComputed(computedAsset);
075
076        return true;
077    }
078
079}