dgraham 2003/09/01 21:42:09 Added: mapper/src/share/org/apache/commons/mapper/jdbc QueryLoader.java Log: Added QueryLoader to simplify the initialization of query Maps. Revision Changes Path 1.1 jakarta-commons-sandbox/mapper/src/share/org/apache/commons/mapper/jdbc/QueryLoader.java Index: QueryLoader.java =================================================================== /* * $Header: /home/cvs/jakarta-commons-sandbox/mapper/src/share/org/apache/commons/mapper/jdbc/QueryLoader.java,v 1.1 2003/09/02 04:42:09 dgraham Exp $ * $Revision: 1.1 $ * $Date: 2003/09/02 04:42:09 $ * * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 2003 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Struts", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact [EMAIL PROTECTED] * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.commons.mapper.jdbc; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Map; import java.util.Properties; /** * QueryLoader loads properties files filled with query name to SQL mappings. * It acts as a registry for sets of queries so that multiple copies of the * same queries aren't loaded into memory. * * @author David Graham */ public class QueryLoader { /** * The Singleton instance of this class. */ private static final QueryLoader instance = new QueryLoader(); /** * @return The Singleton instance. */ public static QueryLoader getInstance() { return instance; } /** * Maps query set names to Maps of their queries. */ private Map queries = new HashMap(); /** * QueryLoader constructor. */ protected QueryLoader() { super(); } /** * Loads a Map of query names to SQL values. The Maps are cached so a * subsequent request to load queries from the same path will return * the cached Map. * @param path The path that the ClassLoader will use to find the file. * @throws IOException * @throws IllegalArgumentException if the ClassLoader can't find a file at * the given path. */ public synchronized Map load(String path) throws IOException { Map queryMap = (Map) this.queries.get(path); if (queryMap == null) { queryMap = this.loadQueries(path); this.queries.put(path, queryMap); } return queryMap; } /** * Loads a properties file into a Map object. * @param path The path that the ClassLoader will use to find the file. * @throws IOException */ private Map loadQueries(String path) throws IOException { InputStream in = QueryLoader.class.getResourceAsStream(path); if (in == null) { throw new IllegalArgumentException(path + " not found."); } Properties props = new Properties(); props.load(in); return new HashMap(props); } }
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