001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.betwixt.io.id; 018 019 020 /** <p>Generates <code>ID</code>'s in numeric sequence. 021 * A simple counter is used. 022 * Every time that {@link #nextIdImpl} is called, 023 * this counter is incremented.</p> 024 * 025 * <p>By default, the counter starts at zero. 026 * A user can set the initial value by using the 027 * {@link #SequentialIDGenerator(int start)} constructor.</p> 028 * 029 * @author <a href="mailto:rdonkin@apache.org">Robert Burrell Donkin</a> 030 * @version $Revision: 438373 $ 031 */ 032 public final class SequentialIDGenerator extends AbstractIDGenerator { 033 034 /** Counter used to assign <code>ID</code>'s */ 035 private int counter = 0; 036 037 /** 038 * Base constructor. 039 * Counter starts at zero. 040 */ 041 public SequentialIDGenerator() {} 042 043 /** 044 * Constructor sets the start value for the counter. 045 * 046 * <p><strong>Note</strong> since the counter increments 047 * before returning the next value, 048 * first <code>ID</code> generated will be <em>one more</em> 049 * than the given <code>start</code> parameter.</p> 050 * 051 * @param start start the counting at this value 052 */ 053 public SequentialIDGenerator(int start) { 054 this.counter = start; 055 } 056 057 /** 058 * Increment counter and then return value. 059 * 060 * @return one more than the current counter (converted to a string) 061 */ 062 public String nextIdImpl() { 063 return Integer.toString(++counter); 064 } 065 066 /** 067 * Gets the current counter value 068 * 069 * @return the last ID in the sequence 070 */ 071 public int getCount() { 072 return counter; 073 } 074 }