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.commons.AnnotationProvider;
018import org.apache.tapestry5.commons.ObjectLocator;
019import org.apache.tapestry5.commons.ObjectProvider;
020import org.apache.tapestry5.commons.services.TypeCoercer;
021import org.apache.tapestry5.ioc.annotations.IntermediateType;
022import org.apache.tapestry5.ioc.annotations.Symbol;
023import org.apache.tapestry5.ioc.services.Builtin;
024import org.apache.tapestry5.ioc.services.SymbolSource;
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}