    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
    015package org.apache.tapestry5.ioc.internal.services;
    016
    017import org.apache.tapestry5.ioc.AnnotationProvider;
    018import org.apache.tapestry5.ioc.ObjectLocator;
    019import org.apache.tapestry5.ioc.ObjectProvider;
    020import org.apache.tapestry5.ioc.annotations.IntermediateType;
    021import org.apache.tapestry5.ioc.annotations.Symbol;
    022import org.apache.tapestry5.ioc.services.Builtin;
    023import org.apache.tapestry5.ioc.services.SymbolSource;
    024import org.apache.tapestry5.ioc.services.TypeCoercer;
    025
    026/**
    027 * Performs an injection based on a {@link Symbol} annotation.
    028 */
    029public 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    @Override
    044    public <T> T provide(Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
    045    {
    046        Symbol annotation = annotationProvider.getAnnotation(Symbol.class);
    047
    048        if (annotation == null) return null;
    049
    050        Object value = symbolSource.valueForSymbol(annotation.value());
    051
    052        IntermediateType it = annotationProvider.getAnnotation(IntermediateType.class);
    053
    054        if (it != null) value = typeCoercer.coerce(value, it.value());
    055
    056        return typeCoercer.coerce(value, objectType);
    057    }
    058
    059}