001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.math.util;
019
020 import java.io.Serializable;
021
022 import org.apache.commons.math.MathException;
023 import org.apache.commons.math.exception.util.LocalizedFormats;
024
025 /**
026 * A Default NumberTransformer for java.lang.Numbers and Numeric Strings. This
027 * provides some simple conversion capabilities to turn any java.lang.Number
028 * into a primitive double or to turn a String representation of a Number into
029 * a double.
030 *
031 * @version $Revision: 1073658 $ $Date: 2011-02-23 10:45:42 +0100 (mer. 23 f??vr. 2011) $
032 */
033 public class DefaultTransformer implements NumberTransformer, Serializable {
034
035 /** Serializable version identifier */
036 private static final long serialVersionUID = 4019938025047800455L;
037
038 /**
039 * @param o the object that gets transformed.
040 * @return a double primitive representation of the Object o.
041 * @throws MathException if it cannot successfully be transformed.
042 * @see <a href="http://commons.apache.org/collections/api-release/org/apache/commons/collections/Transformer.html">Commons Collections Transformer</a>
043 */
044 public double transform(Object o) throws MathException {
045 if (o == null) {
046 throw new MathException(LocalizedFormats.OBJECT_TRANSFORMATION);
047 }
048
049 if (o instanceof Number) {
050 return ((Number)o).doubleValue();
051 }
052
053 try {
054 return Double.valueOf(o.toString()).doubleValue();
055 } catch (NumberFormatException e) {
056 throw new MathException(e,
057 LocalizedFormats.CANNOT_TRANSFORM_TO_DOUBLE, e.getMessage());
058 }
059 }
060
061 /** {@inheritDoc} */
062 @Override
063 public boolean equals(Object other) {
064 if (this == other) {
065 return true;
066 }
067 if (other == null) {
068 return false;
069 }
070 return other instanceof DefaultTransformer;
071 }
072
073 /** {@inheritDoc} */
074 @Override
075 public int hashCode() {
076 // some arbitrary number ...
077 return 401993047;
078 }
079
080 }