Coverage Report - org.apache.commons.dbutils.QueryLoader
 
Classes in this File Line Coverage Branch Coverage Complexity
QueryLoader
0%
0/18
0%
0/4
1.6
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  *
 9  
  *      http://www.apache.org/licenses/LICENSE-2.0
 10  
  *
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.dbutils;
 18  
 
 19  
 import java.io.IOException;
 20  
 import java.io.InputStream;
 21  
 import java.util.HashMap;
 22  
 import java.util.Map;
 23  
 import java.util.Properties;
 24  
 
 25  
 /**
 26  
  * <code>QueryLoader</code> is a registry for sets of queries so 
 27  
  * that multiple copies of the same queries aren't loaded into memory.
 28  
  * This implementation loads properties files filled with query name to 
 29  
  * SQL mappings.  This class is thread safe.
 30  
  */
 31  
 public class QueryLoader {
 32  
 
 33  
     /**
 34  
      * The Singleton instance of this class.
 35  
      */
 36  0
     private static final QueryLoader instance = new QueryLoader();
 37  
 
 38  
     /**
 39  
      * Return an instance of this class.
 40  
      * @return The Singleton instance.
 41  
      */
 42  
     public static QueryLoader instance() {
 43  0
         return instance;
 44  
     }
 45  
 
 46  
     /**
 47  
      * Maps query set names to Maps of their queries.
 48  
      */
 49  0
     private final Map queries = new HashMap();
 50  
 
 51  
     /**
 52  
      * QueryLoader constructor.
 53  
      */
 54  
     protected QueryLoader() {
 55  0
         super();
 56  0
     }
 57  
 
 58  
     /**
 59  
      * Loads a Map of query names to SQL values.  The Maps are cached so a 
 60  
      * subsequent request to load queries from the same path will return
 61  
      * the cached Map.
 62  
      * 
 63  
      * @param path The path that the ClassLoader will use to find the file. 
 64  
      * This is <strong>not</strong> a file system path.  If you had a jarred
 65  
      * Queries.properties file in the com.yourcorp.app.jdbc package you would 
 66  
      * pass "/com/yourcorp/app/jdbc/Queries.properties" to this method.
 67  
      * @throws IOException if a file access error occurs
 68  
      * @throws IllegalArgumentException if the ClassLoader can't find a file at
 69  
      * the given path.
 70  
      * @return Map of query names to SQL values
 71  
      */
 72  
     public synchronized Map load(String path) throws IOException {
 73  
 
 74  0
         Map queryMap = (Map) this.queries.get(path);
 75  
 
 76  0
         if (queryMap == null) {
 77  0
             queryMap = this.loadQueries(path);
 78  0
             this.queries.put(path, queryMap);
 79  
         }
 80  
 
 81  0
         return queryMap;
 82  
     }
 83  
 
 84  
     /**
 85  
      * Loads a set of named queries into a Map object.  This implementation
 86  
      * reads a properties file at the given path.
 87  
      * @param path The path that the ClassLoader will use to find the file.
 88  
      * @throws IOException if a file access error occurs
 89  
      * @throws IllegalArgumentException if the ClassLoader can't find a file at
 90  
      * the given path.
 91  
      * @since DbUtils 1.1
 92  
      * @return Map of query names to SQL values
 93  
      */
 94  
     protected Map loadQueries(String path) throws IOException {
 95  0
         InputStream in = getClass().getResourceAsStream(path);
 96  
 
 97  0
         if (in == null) {
 98  0
             throw new IllegalArgumentException(path + " not found.");
 99  
         }
 100  
 
 101  0
         Properties props = new Properties();
 102  0
         props.load(in);
 103  
 
 104  
         // Copy to HashMap for better performance
 105  0
         return new HashMap(props);
 106  
     }
 107  
     
 108  
     /**
 109  
      * Removes the queries for the given path from the cache.
 110  
      * @param path The path that the queries were loaded from.
 111  
      */
 112  
     public synchronized void unload(String path){
 113  0
         this.queries.remove(path);
 114  0
     }
 115  
 
 116  
 }