content: /*
   * StreamProvider.java January 2010
   *
   * Copyright (C) 2010, Niall Gallagher <niallg@users.sf.net>
   *
   * 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 com.aliyun.odps.simpleframework.xml.stream;
  
  import java.io.InputStream;
  import java.io.Reader;
  
  import javax.xml.stream.XMLEventReader;
  import javax.xml.stream.XMLInputFactory;
  
  /**
   * The <code>StreamProvider</code> object is used to provide event
   * reader implementations for StAX. Wrapping the mechanics of the
   * StAX framework within a <code>Provider</code> ensures that it can
   * be plugged in without any dependencies. This allows other parsers
   * to be swapped in should there be such a requirement.
   * 
   * @author Niall Gallagher
   * 
   * @see StreamProvider
   */
  class StreamProvider implements Provider {
     
     /**
      * This is the factory that is used to create StAX parsers.
      */
     private final XMLInputFactory factory;
     
     /**
      * Constructor for the <code>StreamProvider</code> object. This
      * is used to instantiate a parser factory that will be used to
      * create parsers when requested. Instantiating the factory up
      * front also checks that the framework is fully supported.
      */
     public StreamProvider() {
        this.factory = XMLInputFactory.newInstance();
        this.factory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
        this.factory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
     }
  
     /**
      * This provides an <code>EventReader</code> that will read from
      * the specified input stream. When reading from an input stream
      * the character encoding should be taken from the XML prolog or
      * it should default to the UTF-8 character encoding.
      * 
      * @param source this is the stream to read the document with
      * 
      * @return this is used to return the event reader implementation
      */
     public EventReader provide(InputStream source) throws Exception {
        return provide(factory.createXMLEventReader(source));
     }
     
     /**
      * This provides an <code>EventReader</code> that will read from
      * the specified reader. When reading from a reader the character
      * encoding should be the same as the source XML document.
      * 
      * @param source this is the reader to read the document with
      * 
      * @return this is used to return the event reader implementation
      */
     public EventReader provide(Reader source) throws Exception {
        return provide(factory.createXMLEventReader(source));
     }
     
     /**
      * This provides an <code>EventReader</code> that will read from
      * the specified reader. The returned event reader is basically
      * a wrapper for the provided StAX implementation.
      * 
      * @param source this is the reader to read the document with
      * 
      * @return this is used to return the event reader implementation
      */
     private EventReader provide(XMLEventReader source) throws Exception {
        return new StreamReader(source);
     }
  }