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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  }