n3jenawriter.java

Jena推理机

/*
 * (c) Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
 * [See end of file]
 */

// To do:
//   Better detection of illegal characters in qnames (? and = for example) 

package com.hp.hpl.jena.n3;

//import org.apache.commons.logging.*;
import java.io.OutputStream;
import java.io.Writer;

import com.hp.hpl.jena.JenaRuntime;
import com.hp.hpl.jena.rdf.model.*;

/** Entry point for N3 writers.  This writer will choose the actual writer
 *  to use by looking at the system property
 *  <code>com.hp.hpl.jena.n3.N3JenaWriter.writer</code> to get the
 *  writer name.
 *  <p>
 *  The following N3 writers are provided:
 *  <ul>
 *  <li>N3-PP: Pretty Printer (the default)</li>
 *  <li>N3-PLAIN: Plain, record/frame-oriented format</li> 
 *  <li>N3-TRIPLES: Triples, with prefixes.</li>
 *  </ul>
 *  </p>
 *
 * @author		Andy Seaborne
 * @version 	$Id: N3JenaWriter.java,v 1.31 2007/01/02 11:48:32 andy_seaborne Exp $
 */



public class N3JenaWriter implements RDFWriter
{
    //static Log logger = LogFactory.getLog(N3JenaWriter.class) ;
    static public boolean DEBUG = false ;
    
    // Note: properties are URIs, not java convention package/class names.
    static protected final String propBase = "http://jena.hpl.hp.com/n3/properties/" ;
    
    /** Compatibility.
     * @deprecated Set <code>com.hp.hpl.jena.n3.N3JenaWriter.writer</code> to the name of the writer instead.
     */
    
    static public final String propWriteSimple = "com.hp.hpl.jena.n3.N3JenaWriter.writeSimple" ;
    
    /** System property name that sets the default N3 writer name */   
    static public final String propWriterName = propBase+"writer" ;

    /**
     * General name for the N3 writer.  Will make a decision on exactly which
     * writer to use (pretty writer, plain writer or simple writer) when created.
     * Default is the pretty writer but can be overridden with system property
     * <code>com.hp.hpl.jena.n3.N3JenaWriter.writer</code>.  
     */
     
    static public final String n3Writer              = "N3" ;
    
    /**
     * Name of the N3 pretty writer.  The pretty writer
     * uses a frame-like layout, with prefixing, clustering like properties
     * and embedding one-referenced bNodes.
     */
    static public final String n3WriterPrettyPrinter = "N3-PP" ;
    
    /**
     * Name of the N3 plain writer.  The plain writer writes records
     * by subject.
     */
    static public final String n3WriterPlain         = "N3-PLAIN" ;
    
    /**
     * Name of the N3 triples writer. This writer writes one line per statement,
     * like N-Triples, but does N3-style prefixing.
     */
    static public final String n3WriterTriples       = "N3-TRIPLES" ;
    
    /**
     * Alternative name for the N3 triples writer.
     */
    static public final String n3WriterTriplesAlt    = "N3-TRIPLE" ;

    /**
     * Turtle writer.
     * http://www.dajobe.org/2004/01/turtle/
     */
    static public final String turtleWriter          = "TURTLE" ;
    static public final String turtleWriterAlt1      = "Turtle" ;
    static public final String turtleWriterAlt2      = "TTL" ;
    
    protected N3JenaWriterCommon writer = null ;
    
    public N3JenaWriter() { writer = chooseWriter() ; }
    public N3JenaWriter(N3JenaWriterCommon w) { writer = w ;}
    
    N3JenaWriterCommon chooseWriter()
    {
        // Compatibility with Jena1
        if ( JenaRuntime.getSystemProperty(propWriteSimple, "false").equals("true"))
            return new N3JenaWriterCommon() ;
        
        // Choose the writer
        String writerName = JenaRuntime.getSystemProperty(propWriterName) ;
        if ( writerName == null ||
             writerName.equals("N3") || writerName.equals(n3WriterPrettyPrinter) )
            return new N3JenaWriterPP() ;
        
        if ( writerName.equalsIgnoreCase(n3WriterPlain) )
            return new N3JenaWriterCommon() ;
        
        if ( writerName.equalsIgnoreCase(n3WriterTriples) ||
             writerName.equalsIgnoreCase(n3WriterTriplesAlt) )
            return new N3JenaWriterTriples() ;
            
        if ( writerName.equalsIgnoreCase(turtleWriter) )
        {
            N3JenaWriterPP w = new N3JenaWriterPP() ;
            w.useWellKnownPropertySymbols = false ;
            return w ;
        }
        
        // Don't know or default.
        return new N3JenaWriterPP() ;
    }
    
    
    /** Write the model out in N3, encoded in in UTF-8
     * @see #write(Model,Writer,String)
     */

    public void write(Model model, Writer out, String base) 
    {
        writer.write(model, out, base) ;
    }

    /** Write the model out in N3.  The writer should be one suitable for UTF-8 which
    * excludes a PrintWriter or a FileWriter which use default character set.
    *
    * Examples:
    * <pre>
    * try {
    *      Writer w =  new BufferedWriter(new OutputStreamWriter(output, "UTF-8")) ;
    *      model.write(w, base) ;
    *      try { w.flush() ; } catch (IOException ioEx) {}
    *  } catch (java.io.UnsupportedEncodingException ex) {} //UTF-8 is required so can't happen
    * </pre>
    * or
    * <pre>
    * try {
    *     OutputStream out = new FileOutputStream(file) ;
    *     Writer w =  new BufferedWriter(new OutputStreamWriter(out, "UTF-8")) ;
    *     model.write(w, base) ;
    * }
    * catch (java.io.UnsupportedEncodingException ex) {}
    * catch (java.io.FileNotFoundException noFileEx) { ... }
    * </pre>
    * @see #write(Model,Writer,String)
    */

    public void write(Model model, OutputStream out, String base) 
    {
        writer.write(model, out, base) ;
   }


    /**
     * @see com.hp.hpl.jena.rdf.model.RDFWriter#setProperty(java.lang.String, java.lang.Object)
     */
    public Object setProperty(String propName, Object propValue) 
    {
        return writer.setProperty(propName, propValue) ;
    }

    /**
     * @see com.hp.hpl.jena.rdf.model.RDFWriter#setErrorHandler(com.hp.hpl.jena.rdf.model.RDFErrorHandler)
     */
    public RDFErrorHandler setErrorHandler(RDFErrorHandler errHandler)
    {
        return writer.setErrorHandler(errHandler) ;
    }
   
}

/*
 *  (c) Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
 *  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */