Package org.geotools.xsd

Class StreamingParser

  • public class StreamingParser
extends Object
    XML parser capable of streaming.

    Performs the same task as Parser, with the addition that objects are streamed back to the client. Streaming can occur in a number of different modes.

    As an example consider the following gml document: 

     <test:TestFeatureCollection xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:gml="http://www.opengis.net/gml"
        xmlns:test="http://www.geotools.org/test"
        xsi:schemaLocation="http://www.geotools.org/test test.xsd">

   <gml:featureMember>
      <test:TestFeature fid="0">
              ...
      </test:TestFeature>
   </gml:featureMember>

   <gml:featureMember>
      <test:TestFeature fid="1">
              ...
      </test:TestFeature>
   </gml:featureMember>

   <gml:featureMember>
      <test:TestFeature fid="2">
              ....
      </test:TestFeature>
   </gml:featureMember>

 </test:TestFeatureCollection>
    And suppose we want to stream back each feature as it is parsed.

    1. Element Name

    Objects are streamed back when an element of a particular name has been parsed. 
        Configuration configuration = new GMLConfiguration();
    QName elementName = new QName( "http://www.geotools.org/test", "TestFeature" );

    StreamingParser parser = new StreamingParser( configuration, elementName );

    Feature f = null;
    while ( ( f = parser.parse() ) != null ) {
       ...
    }

    2. Type

    Objects are streamed back when an element has been parsed into an object of a particular type. 
        Configuration configuration = new GMLConfiguration();
    StreamingParser parser = new StreamingParser( configuration, Feature.class );

    Feature f = null;
    while ( ( f = parser.parse() ) != null ) {
       ...
    }

    3. Xpath Expression

    Objects are streamed back when an element has been parsed which matches a particular xpath expression. 
        Configuration configuration = new GMLConfiguration();
    String xpath = "//TestFeature";
    StreamingParser parser = new StreamingParser( configuration, xpath );

    Feature f = null;
    while ( ( f = parser.parse() ) != null ) {
       ...
    }
    PullParser offers similar functionality out of a pull parser instead of a SAX parser, it's supposed to be better, but won't (yet) cover the entire functionality offered by StreamingParser
    Author:
    Justin Deoliveira, The Open Planning Project