View Javadoc

1   /*
2    * Copyright 2004-2009 the Seasar Foundation and the Others.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
13   * either express or implied. See the License for the specific language
14   * governing permissions and limitations under the License.
15   */
16  package org.seasar.cubby.spi.impl;
17  
18  import static org.seasar.cubby.internal.util.LogMessages.format;
19  
20  import java.util.Collection;
21  import java.util.Map;
22  import java.util.TreeMap;
23  
24  import org.seasar.cubby.converter.Converter;
25  import org.seasar.cubby.spi.ConverterProvider;
26  
27  /**
28   * コンバータプロバイダのスケルトン実装です。
29   * 
30   * @author baba
31   */
32  public abstract class AbstractConverterProvider implements ConverterProvider {
33  
34  	/**
35  	 * コンバータの一覧を返します。
36  	 * 
37  	 * @return コンバータの一覧
38  	 */
39  	protected abstract Collection<Converter> getConverters();
40  
41  	/**
42  	 * {@inheritDoc}
43  	 */
44  	public Converter getConverter(final Class<? extends Converter> converterType) {
45  		for (final Converter converter : getConverters()) {
46  			if (converterType.isAssignableFrom(converter.getClass())) {
47  				return converter;
48  			}
49  		}
50  		throw new IllegalArgumentException(format("ECUB0110", converterType));
51  	}
52  
53  	/**
54  	 * {@inheritDoc}
55  	 */
56  	public Converter getConverter(final Class<?> parameterType,
57  			final Class<?> objectType) {
58  		final Class<?> destType = ConversionUtils
59  				.getWrapperClassIfPrimitive(objectType);
60  		final Converter converter = getDistanceTable(parameterType, destType);
61  		return converter;
62  	}
63  
64  	private Converter getDistanceTable(final Class<?> parameterType,
65  			final Class<?> objectType) {
66  		final Map<Integer, Converter> distanceTable = new TreeMap<Integer, Converter>();
67  		for (final Converter converter : getConverters()) {
68  			if (!converter.canConvert(parameterType, objectType)) {
69  				continue;
70  			}
71  			final int distance = getDistance(converter.getObjectType(),
72  					objectType);
73  			distanceTable.put(distance, converter);
74  		}
75  		if (distanceTable.isEmpty()) {
76  			return null;
77  		}
78  		return distanceTable.values().iterator().next();
79  	}
80  
81  	private int getDistance(final Class<?> assigner, final Class<?> assignee) {
82  		return getDistance(assigner, assignee, 0);
83  	}
84  
85  	private int getDistance(final Class<?> assigner, final Class<?> assignee,
86  			final int distance) {
87  		if (assignee.equals(assigner)) {
88  			return distance;
89  		}
90  		if (Enum.class.equals(assigner) && assignee.isEnum()) {
91  			return distance + 5;
92  		}
93  		if (isImplements(assigner, assignee)) {
94  			return distance + 5;
95  		}
96  
97  		final Class<?> superClass = assigner.getSuperclass();
98  		if (superClass == null) {
99  			return distance + 10;
100 		}
101 		return getDistance(superClass, assignee, distance + 10);
102 	}
103 
104 	private boolean isImplements(final Class<?> assigner,
105 			final Class<?> assignee) {
106 		return !assigner.isInterface() && assignee.isInterface()
107 				&& assignee.isAssignableFrom(assigner);
108 	}
109 
110 }