/*
* Copyright (c) 2005, Graph Builder
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of Graph Builder nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.graphbuilder.math;
/**
A node of an expression tree that has exactly 2 children, a left child and a right child. After the
children are evaluated, a mathematical operation is applied and the result is returned.
*/
public abstract class
OpNode extends
Expression {
protected
Expression leftChild = null;
protected
Expression rightChild = null;
public
OpNode(
Expression leftChild,
Expression rightChild) {
setLeftChild(
leftChild);
setRightChild(
rightChild);
}
public void
setLeftChild(
Expression x) {
checkBeforeAccept(
x);
if (
leftChild != null)
leftChild.
parent = null;
x.
parent = this;
leftChild =
x;
}
public void
setRightChild(
Expression x) {
checkBeforeAccept(
x);
if (
rightChild != null)
rightChild.
parent = null;
x.
parent = this;
rightChild =
x;
}
public
Expression getLeftChild() {
return
leftChild;
}
public
Expression getRightChild() {
return
rightChild;
}
/**
Returns the text symbol that represents the operation.
*/
public abstract
String getSymbol();
}