- /*
- * $Header: /home/cvs/jakarta-commons/dbutils/src/java/org/apache/commons/dbutils/QueryLoader.java,v 1.1 2003/11/02 19:15:23 dgraham Exp $
- * $Revision: 1.1 $
- * $Date: 2003/11/02 19:15:23 $
- *
- * ====================================================================
- *
- * 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 acknowledgement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgement may appear in the software itself,
- * if and wherever such third-party acknowledgements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", 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 apache@apache.org.
- *
- * 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 Software Foundation.
- *
- * 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.dbutils;
-
- import java.io.IOException;
- import java.io.InputStream;
- import java.util.HashMap;
- import java.util.Map;
- import java.util.Properties;
-
- /**
- * <code>QueryLoader</code> 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. This class is thread
- * safe.
- *
- * @author David Graham
- */
- public class QueryLoader {
-
- /**
- * The Singleton instance of this class.
- */
- private static final QueryLoader instance = new QueryLoader();
-
- /**
- * Return an instance of this class.
- * @return The Singleton instance.
- */
- public static QueryLoader instance() {
- 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.
- * This is <strong>not</strong> a file system path. If you had a jarred
- * Queries.properties file in the com.yourcorp.app.jdbc package you would
- * pass "/com/yourcorp/app/jdbc/Queries.properties" to this method.
- * @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);
-
- // Copy to HashMap for better performance
- return new HashMap(props);
- }
-
- /**
- * Removes the queries for the given path from the cache.
- * @param path The path that the queries were loaded from.
- */
- public synchronized void unload(String path){
- this.queries.remove(path);
- }
-
- }