/*
* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.tools.jstat;
/**
* A class that represents a mathematical expression as a tree structure
* containing operators as interior nodes and operands as leaves. The
* operands can be literals or lazily bound variables.
*
* @author Brian Doherty
* @since 1.5
*/
public class Expression {
private static int nextOrdinal;
private boolean debug = Boolean.getBoolean("Expression.debug");
private Expression left;
private Expression right;
private Operator operator;
private int ordinal = nextOrdinal++;
Expression() {
if (debug) {
System.out.println("Expression " + ordinal + " created");
}
}
void setLeft(Expression left) {
if (debug) {
System.out.println("Setting left on " + ordinal + " to " + left);
}
this.left = left;
}
Expression getLeft() {
return left;
}
void setRight(Expression right) {
if (debug) {
System.out.println("Setting right on " + ordinal + " to " + right);
}
this.right = right;
}
Expression getRight() {
return right;
}
void setOperator(Operator o) {
if (debug) {
System.out.println("Setting operator on " + ordinal + " to " + o);
}
this.operator = o;
}
Operator getOperator() {
return operator;
}
public String toString() {
StringBuilder b = new StringBuilder();
b.append('(');
if (left != null) {
b.append(left.toString());
}
if (operator != null) {
b.append(operator.toString());
if (right != null) {
b.append(right.toString());
}
}
b.append(')');
return b.toString();
}
}