1 /*
   2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
   3  */
   4 /*
   5  * Licensed to the Apache Software Foundation (ASF) under one or more
   6  * contributor license agreements.  See the NOTICE file distributed with
   7  * this work for additional information regarding copyright ownership.
   8  * The ASF licenses this file to You under the Apache License, Version 2.0
   9  * (the "License"); you may not use this file except in compliance with
  10  * the License.  You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20 package org.apache.qetest.xslwrapper;
  21 
  22 import java.util.Properties;
  23 
  24 /**
  25  * Factory static class for creating TransformWrappers.
  26  *
  27  * Includes a 'wrapperMapper' functionality to simplify specifying the 'flavor'
  28  * of a wrapper to create. This is optional, but will allow a user to specify
  29  * newWrapper("trax.file") and get back an instance of an
  30  * org.apache.qetest.xslwrapper.TraxFileWrapper.
  31  */
  32 public class TransformWrapperFactory {
  33 
  34     /**
  35      * Currently known list of implemented wrappers.
  36      * <ul>
  37      * <p>Allows specification of a simple name for each wrapper, so clients 
  38      * don't necessarily have to know the FQCN or fully qualified class name of
  39      * their wrapper.</p>
  40      * </ul>
  41      */
  42     protected final static Properties wrapperMapper = new Properties();
  43 
  44     /**
  45      * Static initializer for wrapperMapper. Attempts to load
  46      * TransformWrapperFactory.properties into our wrapperMapper.
  47      */
  48     static {
  49         // Add a default trax flavor, since it's widely used
  50         // This should be overwritten below if the properties
  51         //  file can be loaded.
  52         wrapperMapper.put("trax.systemId", "org.apache.qetest.xslwrapper.TraxSystemIdWrapper");
  53         wrapperMapper.put("trax.file", "org.apache.qetest.xslwrapper.TraxFileWrapper");
  54         wrapperMapper.put("trax.stream", "org.apache.qetest.xslwrapper.TraxStreamWrapper");
  55         wrapperMapper.put("trax.dom", "org.apache.qetest.xslwrapper.TraxDOMWrapper");
  56         wrapperMapper.put("trax.sax", "org.apache.qetest.xslwrapper.TraxSAXWrapper");
  57         wrapperMapper.put("trax.localPath", "org.apache.qetest.xslwrapper.TraxLocalPathWrapper");
  58         wrapperMapper.put("trax.systemId3", "org.apache.qetest.xslwrapper.TraxSystemId3Wrapper");
  59     }
  60 
  61     /**
  62      * Accessor for our wrapperMapper.
  63      * @return Properties block of wrapper implementations
  64      * that we implicitly know about; may be null if we have none
  65      */
  66     public static final Properties getDescriptions() {
  67         return wrapperMapper;
  68     }
  69 
  70     /**
  71      * Return an instance of a TransformWrapper of requested flavor.
  72      *
  73      * This static factory method creates TransformWrappers for the user. Our
  74      * 'wrapperMapper' functionality allows users to either specify short names
  75      * listed in TransformWrapperFactory.properties (which are mapped to the
  76      * appropriate FQCN's) or to directly supply the FQCN of a wrapper to
  77      * create.
  78      *
  79      * @param flavor to create, either a wrapperMapped one or FQCN
  80      *
  81      * @return instance of a wrapper; will throw an IllegalArgumentException if
  82      * we cannot find the asked-for wrapper class anywhere
  83      */
  84     public static final TransformWrapper newWrapper(String flavor) {
  85         // Attempt to lookup the flavor: if found, use the
  86         //  value we got, otherwise default to the same value
  87         String className = wrapperMapper.getProperty(flavor, flavor);
  88 
  89         try {
  90             // Allow people to use bare classnames in popular packages
  91             Class clazz = Class.forName(className);
  92             return (TransformWrapper) clazz.newInstance();
  93         } catch (ClassNotFoundException | IllegalAccessException | InstantiationException e) {
  94             throw new IllegalArgumentException("newWrapper(" + flavor + ") threw: " + e.toString());
  95         }
  96     }
  97 }