| /* |
| * 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.tools.jstat; |
| |
| import java.util.*; |
| |
| |
| /** |
| * A typesafe enumeration for describing mathematical operators. |
| * |
| * @author Brian Doherty |
| * @since 1.5 |
| */ |
| public abstract class Operator { |
| |
| private static int nextOrdinal = 0; |
| private static HashMap<String, Operator> map = new HashMap<String, Operator>(); |
| |
| private final String name; |
| private final int ordinal = nextOrdinal++; |
| |
| private Operator(String name) { |
| this.name = name; |
| map.put(name, this); |
| } |
| |
| protected abstract double eval(double x, double y); |
| |
| /* Operator '+' */ |
| public static final Operator PLUS = new Operator("+") { |
| protected double eval(double x, double y) { |
| return x + y; |
| } |
| }; |
| |
| /* Operator '-' */ |
| public static final Operator MINUS = new Operator("-") { |
| protected double eval(double x, double y) { |
| return x - y; |
| } |
| }; |
| |
| /* Operator '/' */ |
| public static final Operator DIVIDE = new Operator("/") { |
| protected double eval(double x, double y) { |
| if (y == 0) { |
| return Double.NaN; |
| } |
| return x / y; |
| } |
| }; |
| |
| /* Operator '*' */ |
| public static final Operator MULTIPLY = new Operator("*") { |
| protected double eval(double x, double y) { |
| return x * y; |
| } |
| }; |
| |
| /** |
| * Returns the string representation of this Operator object. |
| * |
| * @return the string representation of this Operator object |
| */ |
| public String toString() { |
| return name; |
| } |
| |
| /** |
| * Maps a string to its corresponding Operator object. |
| * |
| * @param s an string to match against Operator objects. |
| * @return The Operator object matching the given string. |
| */ |
| public static Operator toOperator(String s) { |
| return map.get(s); |
| } |
| |
| /** |
| * Returns an enumeration of the keys for this enumerated type |
| * |
| * @param s an string to match against Operator objects. |
| * @return The Operator object matching the given string. |
| */ |
| protected static Set<?> keySet() { |
| return map.keySet(); |
| } |
| } |