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    1   /*
    2    * Copyright 2002-2006 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.jexl.parser;
    18
    19  import org.apache.commons.jexl.util.Coercion;
    20  import org.apache.commons.jexl.JexlContext;
    21
    22  /***
    23   * Subtraction.
    24   *
    25   * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
    26   * @author <a href="mailto:mhw@kremvax.net">Mark H. Wilkinson</a>
    27   * @version $Id: ASTSubtractNode.java 398325 2006-04-30 12:34:29Z dion $
    28   */
    29  public class ASTSubtractNode extends SimpleNode {
    30      /***
    31       * Create the node given an id.
    32       *
    33       * @param id node id.
    34       */
    35      public ASTSubtractNode(int id) {
    36          super(id);
    37      }
    38
    39      /***
    40       * Create a node with the given parser and id.
    41       *
    42       * @param p a parser.
    43       * @param id node id.
    44       */
    45      public ASTSubtractNode(Parser p, int id) {
    46          super(p, id);
    47      }
    48
    49      /*** {@inheritDoc} */
    50      public Object value(JexlContext context) throws Exception {
    51          Object left = ((SimpleNode) jjtGetChild(0)).value(context);
    52          Object right = ((SimpleNode) jjtGetChild(1)).value(context);
    53
    54          /*
    55           * the spec says 'and', I think 'or'
    56           */
    57          if (left == null && right == null) {
    58              return new Byte((byte) 0);
    59          }
    60
    61          /*
    62           * if anything is float, double or string with ( "." | "E" | "e") coerce
    63           * all to doubles and do it
    64           */
    65          if (left instanceof Float
    66              || left instanceof Double
    67              || right instanceof Float
    68              || right instanceof Double
    69              || (left instanceof String
    70                  && (((String) left).indexOf(".") != -1
    71                      || ((String) left).indexOf("e") != -1
    72                      || ((String) left).indexOf("E") != -1))
    73              || (right instanceof String
    74                  && (((String) right).indexOf(".") != -1
    75                      || ((String) right).indexOf("e") != -1
    76                      || ((String) right).indexOf("E") != -1))) {
    77              Double l = Coercion.coerceDouble(left);
    78              Double r = Coercion.coerceDouble(right);
    79
    80              return new Double(l.doubleValue() - r.doubleValue());
    81          }
    82
    83          /*
    84           * otherwise to longs with thee!
    85           */
    86
    87          Long l = Coercion.coerceLong(left);
    88          Long r = Coercion.coerceLong(right);
    89
    90          return new Long(l.longValue() - r.longValue());
    91
    92      }
    93
    94      /*** {@inheritDoc} */
    95      public Object jjtAccept(ParserVisitor visitor, Object data) {
    96          return visitor.visit(this, data);
    97      }
    98  }