content: /*
   * PullProvider.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 org.xmlpull.v1.XmlPullParser;
  import org.xmlpull.v1.XmlPullParserFactory;
   
  /**
   * The <code>PullProvider</code> class is used to provide an event
   * reader that uses the XML pull API available on Google Android. It
   * provides the best performance on Android as it avoids having to
   * build a full DOM model. The <code>EventReader</code> produced by
   * this provider will have full namespace capabilities and also has
   * line numbers available for each of the events that are extracted.
   * 
   * @author Niall Gallagher
   */
  class PullProvider implements Provider {
     
     /**
      * This is used to create a new XML pull parser for the reader.
      */
     private final XmlPullParserFactory factory;
     
     /**
      * Constructor for the <code>PullProvider</code> object. This
      * will instantiate a namespace aware pull parser factory that
      * will be used to parse the XML documents that are read by
      * the framework. If XML pull is not available this will fail.
      */
     public PullProvider() throws Exception {
        this.factory = XmlPullParserFactory.newInstance();
        this.factory.setNamespaceAware(true);
     }
     
     /**
      * 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 {
        XmlPullParser parser = factory.newPullParser();
        
        if(source != null) {
           parser.setInput(source, null);
        }
        return new PullReader(parser);  
     }
     
     /**
      * 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 {
        XmlPullParser parser = factory.newPullParser();
        
        if(source != null) {
           parser.setInput(source);
        }
        return new PullReader(parser);
     }
  }
  