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1   /*
2    * Copyright 2003-2004 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  
17  package org.apache.commons.math.util;
18  
19  import java.io.Serializable;
20  
21  import org.apache.commons.math.MathException;
22  
23  /**
24   * A Default NumberTransformer for java.lang.Numbers and Numeric Strings. This 
25   * provides some simple conversion capabilities to turn any java/lang.Number 
26   * into a primitive double or to turn a String representation of a Number into 
27   * a double.
28   *
29   * @version $Revision: 348519 $ $Date: 2005-11-23 12:12:18 -0700 (Wed, 23 Nov 2005) $
30   */
31  public class DefaultTransformer implements NumberTransformer, Serializable {
32      
33      /** Serializable version identifier */
34      private static final long serialVersionUID = 4019938025047800455L;
35      
36      /**
37       * @param o  the object that gets transformed.
38       * @return a double primitive representation of the Object o.
39       * @throws org.apache.commons.math.MathException If it cannot successfully 
40       * be transformed or is null.
41       * @see org.apache.commons.collections.Transformer#transform(java.lang.Object)
42       */
43      public double transform(Object o) throws MathException{
44  
45          if (o == null) {
46              throw new MathException("Conversion Exception in Transformation, Object is null");
47          }
48  
49          if (o instanceof Number) {
50              return ((Number)o).doubleValue();
51          }
52              
53          try {
54              return new Double(o.toString()).doubleValue();
55          } catch (Exception e) {
56              throw new MathException("Conversion Exception in Transformation: " + e.getMessage(), e);
57          }
58      }
59  }