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    1   /*
    2    * Copyright 2002,2004 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  package org.apache.commons.jexl.parser;
    17
    18  import org.apache.commons.jexl.JexlContext;
    19
    20
    21  /***
    22   *  -
    23   *
    24   *  @author <a href="mailto:mhw@kremvax.net">Mark H. Wilkinson</a>
    25   *  @version $Id: ASTUnaryMinusNode.java,v 1.3 2004/02/28 13:45:20 yoavs Exp $
    26   */
    27  public class ASTUnaryMinusNode extends SimpleNode
    28  {
    29      public ASTUnaryMinusNode(int id)
    30      {
    31          super(id);
    32      }
    33
    34      public ASTUnaryMinusNode(Parser p, int id)
    35      {
    36          super(p, id);
    37      }
    38
    39      /*** Accept the visitor. **/
    40      public Object jjtAccept(ParserVisitor visitor, Object data)
    41      {
    42          return visitor.visit(this, data);
    43      }
    44
    45      public Object value(JexlContext jc)
    46          throws Exception
    47      {
    48          Object val = ((SimpleNode) jjtGetChild(0)).value(jc);
    49
    50          if (val instanceof Integer)
    51          {
    52              return new Integer(- ( ((Integer) val).intValue() ) );
    53          }
    54          else
    55          {
    56              throw new Exception("expression not integer valued");
    57          }
    58      }
    59  }
    60