| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| GroupClazzLoader |
|
| 2.75;2.75 |
| 1 | /* | |
| 2 | * Copyright 2002-2004 The Apache Software Foundation | |
| 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, either express or implied. | |
| 13 | * See the License for the specific language governing permissions and | |
| 14 | * limitations under the License. | |
| 15 | */ | |
| 16 | package org.apache.commons.clazz.common; | |
| 17 | ||
| 18 | import java.util.ArrayList; | |
| 19 | import java.util.Collections; | |
| 20 | import java.util.List; | |
| 21 | ||
| 22 | import org.apache.commons.clazz.Clazz; | |
| 23 | import org.apache.commons.clazz.ClazzLoader; | |
| 24 | import org.apache.commons.clazz.ModelClazzLoader; | |
| 25 | ||
| 26 | /** | |
| 27 | * Aggregates multiple ClazzLoaders, which are invoked one after another | |
| 28 | * according to the ChainOfResponsibility pattern. Note that member clazz | |
| 29 | * loaders are invoked in the order reverse to the order they were added. | |
| 30 | * | |
| 31 | * @author <a href="mailto:dmitri@apache.org">Dmitri Plotnikov</a> | |
| 32 | * @version $Id: GroupClazzLoader.java 155436 2005-02-26 13:17:48Z dirkv $ | |
| 33 | */ | |
| 34 | public class GroupClazzLoader extends ClazzLoader { | |
| 35 | /** | |
| 36 | * List of member loaders. Note that the list is always iterated in the | |
| 37 | * reverse direction, so the loaded add last is the one invoked first. | |
| 38 | */ | |
| 39 | 0 | protected ArrayList loaders = new ArrayList(); |
| 40 | ||
| 41 | public GroupClazzLoader(ModelClazzLoader modelClazzLoader) { | |
| 42 | 0 | super(modelClazzLoader); |
| 43 | 0 | } |
| 44 | ||
| 45 | /** | |
| 46 | * Returns true if the supplied loader "belongs" in the group and can be | |
| 47 | * added to it. The default implementation returns true. | |
| 48 | */ | |
| 49 | public boolean canAddClazzLoader(ClazzLoader loader) { | |
| 50 | 0 | return true; |
| 51 | } | |
| 52 | ||
| 53 | /** | |
| 54 | * Adds a ClazzLoader to the group. ClazzLoaders added last are invoked | |
| 55 | * first. Before the group adds the loader to itself, it checks if any | |
| 56 | * of its members are groups themselves and, if so, tries to add the new | |
| 57 | * loader to those subgroups. | |
| 58 | */ | |
| 59 | public void addClazzLoader(ClazzLoader loader) { | |
| 60 | 0 | for (int i = loaders.size(); --i >= 0;) { |
| 61 | 0 | ClazzLoader member = (ClazzLoader) loaders.get(i); |
| 62 | 0 | if (member instanceof GroupClazzLoader) { |
| 63 | 0 | GroupClazzLoader group = (GroupClazzLoader) member; |
| 64 | 0 | if (group.canAddClazzLoader(loader)) { |
| 65 | 0 | group.addClazzLoader(loader); |
| 66 | 0 | return; |
| 67 | } | |
| 68 | } | |
| 69 | 0 | } |
| 70 | 0 | loaders.add(loader); |
| 71 | 0 | } |
| 72 | ||
| 73 | /** | |
| 74 | * Returns true iff this group has a member loader that has or can construct | |
| 75 | * a Clazz for the supplied instance. | |
| 76 | */ | |
| 77 | public boolean isMember(Object instance) { | |
| 78 | // Note the reverse order | |
| 79 | 0 | for (int i = loaders.size(); --i >= 0;) { |
| 80 | 0 | ClazzLoader loader = (ClazzLoader) loaders.get(i); |
| 81 | 0 | if (loader.isMember(instance)) { |
| 82 | 0 | return true; |
| 83 | } | |
| 84 | 0 | } |
| 85 | 0 | return false; |
| 86 | } | |
| 87 | ||
| 88 | public String getClazzName(Object instance) { | |
| 89 | // Note the reverse order | |
| 90 | 0 | for (int i = loaders.size(); --i >= 0;) { |
| 91 | 0 | ClazzLoader loader = (ClazzLoader) loaders.get(i); |
| 92 | 0 | String name = loader.getClazzName(instance); |
| 93 | 0 | if (name != null) { |
| 94 | 0 | return name; |
| 95 | } | |
| 96 | 0 | } |
| 97 | 0 | return null; |
| 98 | } | |
| 99 | ||
| 100 | /** | |
| 101 | * Given a Clazz name, produces the corresponding Clazz by invoking member | |
| 102 | * loaders one by one until the clazz is found. | |
| 103 | */ | |
| 104 | public Clazz getClazzForName(String name) { | |
| 105 | 0 | Clazz clazz = null; |
| 106 | // Note the reverse order | |
| 107 | 0 | for (int i = loaders.size(); --i >= 0;) { |
| 108 | 0 | ClazzLoader loader = (ClazzLoader) loaders.get(i); |
| 109 | 0 | clazz = loader.getClazzForName(name); |
| 110 | 0 | if (clazz != null) { |
| 111 | 0 | break; |
| 112 | } | |
| 113 | 0 | } |
| 114 | 0 | return clazz; |
| 115 | } | |
| 116 | ||
| 117 | /** | |
| 118 | * @see ClazzLoader#defineClazz(String, Class, Class) | |
| 119 | */ | |
| 120 | public Clazz defineClazz( | |
| 121 | String name, | |
| 122 | Class clazzClass, | |
| 123 | Class instanceClass) | |
| 124 | { | |
| 125 | 0 | Clazz clazz = null; |
| 126 | // Note the reverse order | |
| 127 | 0 | for (int i = loaders.size(); --i >= 0;) { |
| 128 | 0 | ClazzLoader loader = (ClazzLoader) loaders.get(i); |
| 129 | 0 | clazz = loader.defineClazz(name, clazzClass, instanceClass); |
| 130 | 0 | if (clazz != null) { |
| 131 | 0 | break; |
| 132 | } | |
| 133 | 0 | } |
| 134 | 0 | return clazz; |
| 135 | } | |
| 136 | ||
| 137 | /** | |
| 138 | * Returns all clazz loaders registered with this group, | |
| 139 | * in the order of priority | |
| 140 | */ | |
| 141 | public List getClazzLoaders() { | |
| 142 | 0 | return Collections.unmodifiableList(loaders); |
| 143 | } | |
| 144 | ||
| 145 | /** | |
| 146 | * Returns clazzloaders matching the supplied Predicate | |
| 147 | */ | |
| 148 | // public List getClazzLoaders(Predicate predicate) { | |
| 149 | // } | |
| 150 | } |