001// Copyright 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 015package org.apache.tapestry5.ioc.internal.services; 016 017import org.apache.tapestry5.ioc.AnnotationProvider; 018 019import java.lang.annotation.Annotation; 020import java.util.List; 021 022/** 023 * Chain of command for {@link org.apache.tapestry5.ioc.AnnotationProvider}. 024 */ 025public class AnnotationProviderChain implements AnnotationProvider 026{ 027 private final AnnotationProvider[] providers; 028 029 public AnnotationProviderChain(AnnotationProvider[] providers) 030 { 031 this.providers = providers; 032 } 033 034 /** 035 * Creates an AnnotationProvider from the list of providers. Returns either an {@link AnnotationProviderChain} or 036 * the sole element in the list. 037 */ 038 public static AnnotationProvider create(List<AnnotationProvider> providers) 039 { 040 int size = providers.size(); 041 042 if (size == 1) return providers.get(0); 043 044 return new AnnotationProviderChain(providers.toArray(new AnnotationProvider[providers.size()])); 045 } 046 047 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) 048 { 049 for (AnnotationProvider p : providers) 050 { 051 T result = p.getAnnotation(annotationClass); 052 053 if (result != null) return result; 054 } 055 056 return null; 057 } 058}