| 1 | // Copyright 2004-2007 Jean-Francois Poilpret |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package net.sourceforge.hiveutils.util; |
| 16 | |
| 17 | import java.util.ArrayList; |
| 18 | import java.util.List; |
| 19 | |
| 20 | /** |
| 21 | * Utility class to check if the class of an object is a subclass of one class |
| 22 | * in a list. |
| 23 | * |
| 24 | * @author Jean-Francois Poilpret |
| 25 | */ |
| 26 | public class ClassMatcher |
| 27 | { |
| 28 | /** |
| 29 | * Add a class to the list, associated with a value. |
| 30 | * @param clazz Class to be added to the list |
| 31 | * @param value value to be returned (by <code>get()</code> when the passed |
| 32 | * object is an instance of that class. |
| 33 | */ |
| 34 | synchronized public void put(Class clazz, Object value) |
| 35 | { |
| 36 | _patterns.add(new ClassEntry(clazz, value)); |
| 37 | } |
| 38 | |
| 39 | /** |
| 40 | * Search if an object is an instance of one of the classes added to this |
| 41 | * ClassMatcher. For the first class in the list that is a superclass of the |
| 42 | * passed object, the matching value is returned. If there is no such class |
| 43 | * in the list, then <code>null</code> is returned. |
| 44 | * @param o the object to check against the list of classes |
| 45 | * @return the value associated with the first class in the list that is a |
| 46 | * superclass of <code>o</code> |
| 47 | */ |
| 48 | synchronized public Object get(Object o) |
| 49 | { |
| 50 | if (o == null) |
| 51 | { |
| 52 | return null; |
| 53 | } |
| 54 | |
| 55 | Class<?> clazz = o.getClass(); |
| 56 | for (ClassEntry entry: _patterns) |
| 57 | { |
| 58 | if (entry.getClazz().isAssignableFrom(clazz)) |
| 59 | { |
| 60 | return entry.getValue(); |
| 61 | } |
| 62 | } |
| 63 | return null; |
| 64 | } |
| 65 | |
| 66 | static private class ClassEntry |
| 67 | { |
| 68 | public ClassEntry(Class<?> clazz, Object value) |
| 69 | { |
| 70 | _clazz = clazz; |
| 71 | _value = value; |
| 72 | } |
| 73 | |
| 74 | public Class<?> getClazz() |
| 75 | { |
| 76 | return _clazz; |
| 77 | } |
| 78 | |
| 79 | public Object getValue() |
| 80 | { |
| 81 | return _value; |
| 82 | } |
| 83 | |
| 84 | private final Class _clazz; |
| 85 | private final Object _value; |
| 86 | } |
| 87 | |
| 88 | private final List<ClassEntry> _patterns = new ArrayList<ClassEntry>(); |
| 89 | } |