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