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 import org.apache.commons.betwixt.io.IDGenerator; 020 021 /** <p>Abstract superclass for {@link IDGenerator} implementations.</p> 022 * 023 * <p>It implements the entire <code>IDGenerator</code> interface. 024 * When <code>nextId</code> is called, 025 * this class sets the <code>LastId</code> property (as well 026 * as returning the value). 027 * Subclasses should override {@link #nextIdImpl}.</p> 028 * 029 * @author <a href="mailto:rdonkin@apache.org">Robert Burrell Donkin</a> 030 * @version $Revision: 438373 $ 031 */ 032 public abstract class AbstractIDGenerator implements IDGenerator { 033 034 /** Last <code>ID</code> returned */ 035 private String lastId = "0"; 036 037 /** 038 * Gets last <code>ID</code> returned. 039 * 040 * @return the last id created by the generated 041 */ 042 public final String getLastId() { 043 return lastId; 044 } 045 046 /** 047 * <p>Generate next <code>ID</code>.</p> 048 * 049 * <p>This method obtains the next <code>ID</code> from subclass 050 * and then uses this to set the <code>LastId</code> property.</p> 051 * 052 * @return the next id generated 053 */ 054 public final String nextId() { 055 lastId = nextIdImpl(); 056 return lastId; 057 } 058 059 /** 060 * Subclasses should <strong>provide an implementation</strong> for this method. 061 * This implementation needs only provide the next <code>ID</code> 062 * value (according to it's algorithm). 063 * Setting the <code>LastId</code> property can be left to this class. 064 * 065 * @return the next id generated 066 */ 067 protected abstract String nextIdImpl(); 068 }