1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.util; 18 19 import java.io.Serializable; 20 import java.util.Collection; 21 import java.util.HashMap; 22 import java.util.Map; 23 import java.util.Set; 24 25 import org.apache.commons.math.MathException; 26 27 /** 28 * This TansformerMap automates the transformation of mixed object types. 29 * It provides a means to set NumberTransformers that will be selected 30 * based on the Class of the object handed to the Maps 31 * <code>double transform(Object o)</code> method. 32 * @version $Revision: 922713 $ $Date: 2010-03-14 02:26:13 +0100 (dim. 14 mars 2010) $ 33 */ 34 public class TransformerMap implements NumberTransformer, Serializable { 35 36 /** Serializable version identifier */ 37 private static final long serialVersionUID = 4605318041528645258L; 38 39 /** 40 * A default Number Transformer for Numbers and numeric Strings. 41 */ 42 private NumberTransformer defaultTransformer = null; 43 44 /** 45 * The internal Map. 46 */ 47 private Map<Class<?>, NumberTransformer> map = null; 48 49 /** 50 * Build a map containing only the default transformer. 51 */ 52 public TransformerMap() { 53 map = new HashMap<Class<?>, NumberTransformer>(); 54 defaultTransformer = new DefaultTransformer(); 55 } 56 57 /** 58 * Tests if a Class is present in the TransformerMap. 59 * @param key Class to check 60 * @return true|false 61 */ 62 public boolean containsClass(Class<?> key) { 63 return map.containsKey(key); 64 } 65 66 /** 67 * Tests if a NumberTransformer is present in the TransformerMap. 68 * @param value NumberTransformer to check 69 * @return true|false 70 */ 71 public boolean containsTransformer(NumberTransformer value) { 72 return map.containsValue(value); 73 } 74 75 /** 76 * Returns the Transformer that is mapped to a class 77 * if mapping is not present, this returns null. 78 * @param key The Class of the object 79 * @return the mapped NumberTransformer or null. 80 */ 81 public NumberTransformer getTransformer(Class<?> key) { 82 return map.get(key); 83 } 84 85 /** 86 * Sets a Class to Transformer Mapping in the Map. If 87 * the Class is already present, this overwrites that 88 * mapping. 89 * @param key The Class 90 * @param transformer The NumberTransformer 91 * @return the replaced transformer if one is present 92 */ 93 public NumberTransformer putTransformer(Class<?> key, NumberTransformer transformer) { 94 return map.put(key, transformer); 95 } 96 97 /** 98 * Removes a Class to Transformer Mapping in the Map. 99 * @param key The Class 100 * @return the removed transformer if one is present or 101 * null if none was present. 102 */ 103 public NumberTransformer removeTransformer(Class<?> key) { 104 return map.remove(key); 105 } 106 107 /** 108 * Clears all the Class to Transformer mappings. 109 */ 110 public void clear() { 111 map.clear(); 112 } 113 114 /** 115 * Returns the Set of Classes used as keys in the map. 116 * @return Set of Classes 117 */ 118 public Set<Class<?>> classes() { 119 return map.keySet(); 120 } 121 122 /** 123 * Returns the Set of NumberTransformers used as values 124 * in the map. 125 * @return Set of NumberTransformers 126 */ 127 public Collection<NumberTransformer> transformers() { 128 return map.values(); 129 } 130 131 /** 132 * Attempts to transform the Object against the map of 133 * NumberTransformers. Otherwise it returns Double.NaN. 134 * 135 * @param o the Object to be transformed. 136 * @return the double value of the Object. 137 * @throws MathException if the Object can not be transformed into a Double. 138 * @see org.apache.commons.math.util.NumberTransformer#transform(java.lang.Object) 139 */ 140 public double transform(Object o) throws MathException { 141 double value = Double.NaN; 142 143 if (o instanceof Number || o instanceof String) { 144 value = defaultTransformer.transform(o); 145 } else { 146 NumberTransformer trans = getTransformer(o.getClass()); 147 if (trans != null) { 148 value = trans.transform(o); 149 } 150 } 151 152 return value; 153 } 154 155 /** {@inheritDoc} */ 156 @Override 157 public boolean equals(Object other) { 158 if (this == other) { 159 return true; 160 } 161 if (other instanceof TransformerMap) { 162 TransformerMap rhs = (TransformerMap) other; 163 if (! defaultTransformer.equals(rhs.defaultTransformer)) { 164 return false; 165 } 166 if (map.size() != rhs.map.size()) { 167 return false; 168 } 169 for (Map.Entry<Class<?>, NumberTransformer> entry : map.entrySet()) { 170 if (! entry.getValue().equals(rhs.map.get(entry.getKey()))) { 171 return false; 172 } 173 } 174 return true; 175 } 176 return false; 177 } 178 179 /** {@inheritDoc} */ 180 @Override 181 public int hashCode() { 182 int hash = defaultTransformer.hashCode(); 183 for (NumberTransformer t : map.values()) { 184 hash = hash * 31 + t.hashCode(); 185 } 186 return hash; 187 } 188 189 } 190