001/**
002 * Copyright 2010-2014 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.common.util;
017
018public class Counter {
019
020        int count;
021
022        public Counter() {
023                this(0);
024        }
025
026        public Counter(int startValue) {
027                this.count = startValue;
028        }
029
030        public synchronized int increment() {
031                return increment(1);
032        }
033
034        public synchronized int increment(int amount) {
035                Assert.isTrue(amount > 0, "amount must be > 0");
036                Assert.isTrue(count <= Integer.MAX_VALUE - amount, "max value exceeded");
037                return count += amount;
038        }
039
040        public synchronized int decrement() {
041                return decrement(1);
042        }
043
044        public synchronized int decrement(int amount) {
045                Assert.isTrue(amount > 0, "amount must be > 0");
046                Assert.isTrue(count >= Integer.MIN_VALUE + amount, "min value exceeded");
047                return count -= amount;
048        }
049
050        public synchronized int getValue() {
051                return count;
052        }
053}