    001    // Copyright 2007 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.ioc.internal.services;
    016
    017    import org.apache.tapestry5.ioc.AnnotationProvider;
    018    import org.apache.tapestry5.ioc.ObjectLocator;
    019    import org.apache.tapestry5.ioc.ObjectProvider;
    020    import org.apache.tapestry5.ioc.annotations.IntermediateType;
    021    import org.apache.tapestry5.ioc.annotations.Symbol;
    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
    026    /**
    027     * Performs an injection based on a {@link Symbol} annotation.
    028     */
    029    public class SymbolObjectProvider implements ObjectProvider
    030    {
    031        private final SymbolSource symbolSource;
    032
    033        private final TypeCoercer typeCoercer;
    034
    035        public SymbolObjectProvider(@Builtin SymbolSource symbolSource,
    036
    037                                    @Builtin TypeCoercer typeCoercer)
    038        {
    039            this.symbolSource = symbolSource;
    040            this.typeCoercer = typeCoercer;
    041        }
    042
    043        public <T> T provide(Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
    044        {
    045            Symbol annotation = annotationProvider.getAnnotation(Symbol.class);
    046
    047            if (annotation == null) return null;
    048
    049            Object value = symbolSource.valueForSymbol(annotation.value());
    050
    051            IntermediateType it = annotationProvider.getAnnotation(IntermediateType.class);
    052
    053            if (it != null) value = typeCoercer.coerce(value, it.value());
    054
    055            return typeCoercer.coerce(value, objectType);
    056        }
    057
    058    }