001/* 002 * The contents of this file are subject to the terms of the Common Development and 003 * Distribution License (the License). You may not use this file except in compliance with the 004 * License. 005 * 006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the 007 * specific language governing permission and limitations under the License. 008 * 009 * When distributing Covered Software, include this CDDL Header Notice in each file and include 010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL 011 * Header, with the fields enclosed by brackets [] replaced by your own identifying 012 * information: "Portions copyright [year] [name of copyright owner]". 013 * 014 * Copyright 2015 ForgeRock AS. 015 */ 016 017package org.forgerock.util.generator; 018 019import java.util.UUID; 020import java.util.concurrent.atomic.AtomicLong; 021 022import org.forgerock.util.annotations.VisibleForTesting; 023 024/** 025 * Defines the contract to generate global unique identifiers. 026 */ 027public interface IdGenerator { 028 029 /** 030 * Returns a new globally unique identifier. 031 * @return a new globally unique identifier. 032 */ 033 String generate(); 034 035 /** 036 * The default implementation of {@link IdGenerator}. 037 */ 038 IdGenerator DEFAULT = new SequenceUuidIdGenerator(UUID.randomUUID()); 039 040 /** 041 * Default implementation of the {@link IdGenerator} that will output some ids based on the following pattern : 042 * {@code <uuid> + '-' + an incrementing sequence}. 043 */ 044 final class SequenceUuidIdGenerator implements IdGenerator { 045 046 private final String prefix; 047 private final AtomicLong sequence = new AtomicLong(); 048 049 @VisibleForTesting 050 SequenceUuidIdGenerator(UUID uuid) { 051 this.prefix = uuid.toString(); 052 } 053 054 @Override 055 public String generate() { 056 return prefix + '-' + sequence.getAndIncrement(); 057 } 058 } 059}