001/* 002 * Copyright 2002-2015 the original author or authors. 003 * 004 * Licensed under the Apache 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 * https://www.apache.org/licenses/LICENSE-2.0 009 * 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 */ 016 017package org.springframework.util; 018 019import java.util.UUID; 020import java.util.concurrent.atomic.AtomicLong; 021 022/** 023 * A simple {@link IdGenerator} that starts at 1 and increments by 1 with each call. 024 * 025 * @author Rossen Stoyanchev 026 * @since 4.1.5 027 */ 028public class SimpleIdGenerator implements IdGenerator { 029 030 private final AtomicLong mostSigBits = new AtomicLong(0); 031 032 private final AtomicLong leastSigBits = new AtomicLong(0); 033 034 035 @Override 036 public UUID generateId() { 037 long leastSigBits = this.leastSigBits.incrementAndGet(); 038 if (leastSigBits == 0) { 039 this.mostSigBits.incrementAndGet(); 040 } 041 return new UUID(this.mostSigBits.get(), leastSigBits); 042 } 043 044}