org.openrdf.rio.rdfxml.util
Class RDFXMLPrettyWriter

java.lang.Object
  org.openrdf.rio.rdfxml.RDFXMLWriter
      org.openrdf.rio.rdfxml.util.RDFXMLPrettyWriter

All Implemented Interfaces:

Closeable, Flushable, RDFHandler, RDFWriter

public class RDFXMLPrettyWriter
extends RDFXMLWriter
implements Closeable, Flushable

An extension of RDFXMLWriter that outputs a more concise form of RDF/XML. The resulting output is semantically equivalent to the output of an RDFXMLWriter (it produces the same set of statements), but it is usually easier to read for humans.

This is a quasi-streaming RDFWriter. Statements are cached as long as the striped syntax is followed (i.e. the subject of the next statement is the object of the previous statement) and written to the output when the stripe is broken.

The abbreviations used are typed node elements, empty property elements and striped syntax. Note that these abbreviations require that statements are written in the appropriate order.

Striped syntax means that when the object of a statement is the subject of the next statement we can nest the descriptions in each other.

Example:

 <rdf:Seq>
    <rdf:li>
       <foaf:Person>
          <foaf:knows>
             <foaf:Person>
               <foaf:mbox rdf:resource="..."/>
             </foaf:Person>
          </foaf:knows>
       </foaf:Person>
    </rdf:li>
 </rdf:Seq>
 

Typed node elements means that we write out type information in the short form of

 <foaf:Person rdf:about="...">
     ...
  </foaf:Person>
 

instead of

 <rdf:Description rdf:about="...">
    <rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
     ...
  </rdf:Description>
 

Empty property elements are of the form

 <foaf:Person>
    <foaf:homepage rdf:resource="http://www.cs.vu.nl/˜marta"/>
 </foaf:Person>
 

instead of

 <foaf:Person>
    <foaf:homepage>
       <rdf:Description rdf:about="http://www.cs.vu.nl/˜marta"/>
    <foaf:homepage>
 </foaf:Person>
 

Author:

Peter Mika (pmika@cs.vu.nl)

Field Summary

Fields inherited from class org.openrdf.rio.rdfxml.RDFXMLWriter

headerWritten, lastWrittenSubject, namespaceTable, writer, writingStarted

Constructor Summary

RDFXMLPrettyWriter(OutputStream out)
Creates a new RDFXMLPrintWriter that will write to the supplied OutputStream.

RDFXMLPrettyWriter(Writer out)
Creates a new RDFXMLPrintWriter that will write to the supplied Writer.

Method Summary

void	close()
void	flush()
protected void	flushPendingStatements()
void	handleStatement(Statement st) Handles a statement.
protected void	writeHeader()
protected void	writeIndents(int n) Writes n indents.
protected void	writeStartTag(String namespace, String localName)

Methods inherited from class org.openrdf.rio.rdfxml.RDFXMLWriter

endRDF, getRDFFormat, handleComment, handleNamespace, setNamespace, startRDF, writeAttribute, writeAttribute, writeCharacterData, writeEndOfEmptyTag, writeEndOfStartTag, writeEndTag, writeIndent, writeNewLine, writeStartOfStartTag

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RDFXMLPrettyWriter

public RDFXMLPrettyWriter(OutputStream out)

Creates a new RDFXMLPrintWriter that will write to the supplied OutputStream.

Parameters:

out - The OutputStream to write the RDF/XML document to.

RDFXMLPrettyWriter

public RDFXMLPrettyWriter(Writer out)

Creates a new RDFXMLPrintWriter that will write to the supplied Writer.

Parameters:

out - The Writer to write the RDF/XML document to.

Method Detail

writeHeader

protected void writeHeader()
                    throws IOException

Overrides:

writeHeader in class RDFXMLWriter

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Throws:

IOException

flushPendingStatements

protected void flushPendingStatements()
                               throws IOException

Overrides:

flushPendingStatements in class RDFXMLWriter

Throws:

IOException

handleStatement

public void handleStatement(Statement st)
                     throws RDFHandlerException

Description copied from interface: RDFHandler

Handles a statement.

Specified by:

handleStatement in interface RDFHandler

Overrides:

handleStatement in class RDFXMLWriter

Parameters:

st - The statement.

Throws:

RDFHandlerException - If the RDF handler has encountered an unrecoverable error.

writeStartTag

protected void writeStartTag(String namespace,
                             String localName)
                      throws IOException

Throws:

IOException

writeIndents

protected void writeIndents(int n)
                     throws IOException

Writes n indents.

Throws:

IOException