content: /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.activemq.filter;
  
  
  
  /**
   * An expression which performs an operation on two expression values.
   * 
   * 
   */
  public abstract class BinaryExpression implements Expression {
      protected Expression left;
      protected Expression right;
  
      public BinaryExpression(Expression left, Expression right) {
          this.left = left;
          this.right = right;
      }
  
      public Expression getLeft() {
          return left;
      }
  
      public Expression getRight() {
          return right;
      }
  
  
      /**
       * @see java.lang.Object#toString()
       */
      public String toString() {
          return "(" + left.toString() + " " + getExpressionSymbol() + " " + right.toString() + ")";
      }
  
      /**
       * TODO: more efficient hashCode()
       *
       * @see java.lang.Object#hashCode()
       */
      public int hashCode() {
          return toString().hashCode();
      }
  
      /**
       * TODO: more efficient hashCode()
       *
       * @see java.lang.Object#equals(java.lang.Object)
       */
      public boolean equals(Object o) {
  
          if (o == null || !this.getClass().equals(o.getClass())) {
              return false;
          }
          return toString().equals(o.toString());
  
      }
  
      /**
       * Returns the symbol that represents this binary expression.  For example, addition is
       * represented by "+"
       *
       * @return
       */
      public abstract String getExpressionSymbol();
  
      /**
       * @param expression
       */
      public void setRight(Expression expression) {
          right = expression;
      }
  
      /**
       * @param expression
       */
      public void setLeft(Expression expression) {
          left = expression;
      }
      
  }
  