001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.el; 018 019import javax.servlet.jsp.el.ELException; 020 021/** 022 * 023 * <p>This is the superclass for all binary operators 024 * 025 * @author Nathan Abramson - Art Technology Group 026 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: bayard $ 027 **/ 028 029public abstract class BinaryOperator 030{ 031 //------------------------------------- 032 /** 033 * 034 * Constructor 035 **/ 036 public BinaryOperator () 037 { 038 } 039 040 //------------------------------------- 041 // Expression methods 042 //------------------------------------- 043 /** 044 * 045 * Returns the symbol representing the operator 046 **/ 047 public abstract String getOperatorSymbol (); 048 049 //------------------------------------- 050 /** 051 * 052 * Applies the operator to the given pair of values 053 **/ 054 public abstract Object apply (Object pLeft, 055 Object pRight) 056 throws ELException; 057 058 //------------------------------------- 059 /** 060 * 061 * Returns true if evaluation is necessary given the specified Left 062 * value. The And/OrOperators make use of this 063 **/ 064 public boolean shouldEvaluate (Object pLeft) 065 { 066 return true; 067 } 068 069 //------------------------------------- 070 /** 071 * 072 * Returns true if the operator expects its arguments to be coerced 073 * to Booleans. The And/Or operators set this to true. 074 **/ 075 public boolean shouldCoerceToBoolean () 076 { 077 return false; 078 } 079 080 //------------------------------------- 081}