/*
    * Copyright 2001-2004 The Apache Software Foundation.
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * 
    *      http://www.apache.org/licenses/LICENSE-2.0
    * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package javax.xml.soap;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  
  import java.util.Properties;
  
  /**
   * This class is used to locate factory classes for javax.xml.soap.
   * It has package scope since it is not part of JAXM and should not
   * be accessed from other packages.
   */
  class FactoryFinder {
      /**
       * instantiates an object go the given classname.
       *
       * @param factoryClassName
       * @return a factory object
       * @throws SOAPException
       */
      private static Object newInstance(String factoryClassName) throws SOAPException {
          ClassLoader classloader = null;
          try {
              classloader = Thread.currentThread().getContextClassLoader();
          } catch (Exception exception) {
              throw new SOAPException(exception.toString(), exception);
          }
  
          try {
              Class factory = null;
              if (classloader == null) {
                  factory = Class.forName(factoryClassName);
              } else {
                  try {
                      factory = classloader.loadClass(factoryClassName);
                  } catch (ClassNotFoundException cnfe) {}
              }
              if (factory == null) {
                  classloader = FactoryFinder.class.getClassLoader();
                  factory = classloader.loadClass(factoryClassName);
              }
              return factory.newInstance();
          } catch (ClassNotFoundException classnotfoundexception) {
              throw new SOAPException("Provider " + factoryClassName + " not found", classnotfoundexception);
          } catch (Exception exception) {
              throw new SOAPException("Provider " + factoryClassName + " could not be instantiated: " + exception, exception);
          }
      }
  
      /**
       * Instantiates a factory object given the factory's property name and the
       * default class name.
       *
       * @param factoryPropertyName
       * @param defaultFactoryClassName
       * @return a factory object
       * @throws SOAPException
       */
      static Object find(String factoryPropertyName, String defaultFactoryClassName) throws SOAPException {
          try {
              String factoryClassName = System.getProperty(factoryPropertyName);
              if (factoryClassName != null) {
                  return newInstance(factoryClassName);
              }
          } catch (SecurityException securityexception) {}
  
          try {
              String propertiesFileName = System.getProperty("java.home")
                                          + File.separator + "lib"
                                          + File.separator + "jaxm.properties";
              File file = new File(propertiesFileName);
              if (file.exists()) {
                  FileInputStream fileInput = new FileInputStream(file);
                  Properties properties = new Properties();
                  properties.load(fileInput);
                  fileInput.close();
                  String factoryClassName = properties.getProperty(factoryPropertyName);
                  return newInstance(factoryClassName);
              }
          } catch (Exception exception1) {}
  
         String factoryResource = "META-INF/services/" + factoryPropertyName;
 
         try {
             InputStream inputstream = getResource(factoryResource);
             if (inputstream != null) {
                 BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(inputstream, "UTF-8"));
                 String factoryClassName = bufferedreader.readLine();
                 bufferedreader.close();
                 if ((factoryClassName != null) && !"".equals(factoryClassName)) {
                     return newInstance(factoryClassName);
                 }
             }
         } catch (Exception exception2) {}
 
         if (defaultFactoryClassName == null) {
             throw new SOAPException("Provider for " + factoryPropertyName + " cannot be found", null);
         } else {
             return newInstance(defaultFactoryClassName);
         }
     }
 
     /**
      * Returns an input stream for the specified resource.
      *
      * <p>This method will firstly try
      * <code>ClassLoader.getSystemResourceAsStream()</code> then
      * the class loader of the current thread with
      * <code>getResourceAsStream()</code> and finally attempt
      * <code>getResourceAsStream()</code> on
      * <code>FactoryFinder.class.getClassLoader()</code>.
      *
      * @param factoryResource  the resource name
      * @return  an InputStream that can be used to read that resource, or
      *              <code>null</code> if the resource could not be resolved
      */
     private static InputStream getResource(String factoryResource) {
         ClassLoader classloader = null;
         try {
             classloader = Thread.currentThread().getContextClassLoader();
         } catch (SecurityException securityexception) {}
 
         InputStream inputstream;
         if (classloader == null) {
             inputstream = ClassLoader.getSystemResourceAsStream(factoryResource);
         } else {
             inputstream = classloader.getResourceAsStream(factoryResource);
         }
 
         if (inputstream == null) {
             inputstream = FactoryFinder.class.getClassLoader().getResourceAsStream(factoryResource);
         }
         return inputstream;
     }
 }