    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.Asset;
    018    import org.apache.tapestry5.annotations.Path;
    019    import org.apache.tapestry5.ioc.AnnotationProvider;
    020    import org.apache.tapestry5.ioc.ObjectLocator;
    021    import org.apache.tapestry5.ioc.ObjectProvider;
    022    import org.apache.tapestry5.ioc.services.Builtin;
    023    import org.apache.tapestry5.ioc.services.SymbolSource;
    024    import org.apache.tapestry5.ioc.services.TypeCoercer;
    025    import org.apache.tapestry5.services.AssetSource;
    026    import org.apache.tapestry5.services.Core;
    027
    028    /**
    029     * Exposes assets (in the current locale). The Inject annotation must be supplemented by a {@link Path} annotation, to
    030     * identify what asset to be injected.
    031     */
    032    public class AssetObjectProvider implements ObjectProvider
    033    {
    034        private final AssetSource source;
    035
    036        private final TypeCoercer typeCoercer;
    037
    038        private final SymbolSource symbolSource;
    039
    040        public AssetObjectProvider(@Core AssetSource source,
    041
    042                                   @Builtin TypeCoercer typeCoercer,
    043
    044                                   @Builtin SymbolSource symbolSource)
    045        {
    046            this.source = source;
    047            this.typeCoercer = typeCoercer;
    048            this.symbolSource = symbolSource;
    049        }
    050
    051        /**
    052         * Provides the asset. If the expression does not identify an asset domain, with a prefix, it is assumed to be a
    053         * path on the classpath, relative to the root of the classpath.
    054         *
    055         * @param objectType the type of object (which must be Object or Asset)
    056         * @param locator    not used
    057         */
    058        public <T> T provide(Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
    059        {
    060            Path path = annotationProvider.getAnnotation(Path.class);
    061
    062            if (path == null) return null;
    063
    064            String expanded = symbolSource.expandSymbols(path.value());
    065
    066            Asset asset = source.getAsset(null, expanded, null);
    067
    068            return typeCoercer.coerce(asset, objectType);
    069        }
    070    }