001/* 002 * Copyright 2002-2018 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.dao.support; 018 019import org.apache.commons.logging.Log; 020import org.apache.commons.logging.LogFactory; 021 022import org.springframework.beans.factory.BeanInitializationException; 023import org.springframework.beans.factory.InitializingBean; 024 025/** 026 * Generic base class for DAOs, defining template methods for DAO initialization. 027 * 028 * <p>Extended by Spring's specific DAO support classes, such as: 029 * JdbcDaoSupport, JdoDaoSupport, etc. 030 * 031 * @author Juergen Hoeller 032 * @since 1.2.2 033 * @see org.springframework.jdbc.core.support.JdbcDaoSupport 034 */ 035public abstract class DaoSupport implements InitializingBean { 036 037 /** Logger available to subclasses. */ 038 protected final Log logger = LogFactory.getLog(getClass()); 039 040 041 @Override 042 public final void afterPropertiesSet() throws IllegalArgumentException, BeanInitializationException { 043 // Let abstract subclasses check their configuration. 044 checkDaoConfig(); 045 046 // Let concrete implementations initialize themselves. 047 try { 048 initDao(); 049 } 050 catch (Exception ex) { 051 throw new BeanInitializationException("Initialization of DAO failed", ex); 052 } 053 } 054 055 /** 056 * Abstract subclasses must override this to check their configuration. 057 * <p>Implementors should be marked as {@code final} if concrete subclasses 058 * are not supposed to override this template method themselves. 059 * @throws IllegalArgumentException in case of illegal configuration 060 */ 061 protected abstract void checkDaoConfig() throws IllegalArgumentException; 062 063 /** 064 * Concrete subclasses can override this for custom initialization behavior. 065 * Gets called after population of this instance's bean properties. 066 * @throws Exception if DAO initialization fails 067 * (will be rethrown as a BeanInitializationException) 068 * @see org.springframework.beans.factory.BeanInitializationException 069 */ 070 protected void initDao() throws Exception { 071 } 072 073}