PlainHeader.java

/**
 * File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/header/PlainHeader.java $
 * Revision: $Rev: 191 $
 * Last modified: $Date: 2013-03-03 11:41:43 +0000 (dom, 03 mar 2013) $
 * Last modified by: $Author: mario.arias $
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Contacting the authors:
 *   Mario Arias:               mario.arias@deri.org
 *   Javier D. Fernandez:       jfergar@infor.uva.es
 *   Miguel A. Martinez-Prieto: migumar2@infor.uva.es
 *   Alejandro Andres:          fuzzy.alej@gmail.com
 */

package org.rdfhdt.hdt.header;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.rdfhdt.hdt.enums.RDFNotation;
import org.rdfhdt.hdt.exceptions.IllegalFormatException;
import org.rdfhdt.hdt.exceptions.ParserException;
import org.rdfhdt.hdt.hdt.HDTVocabulary;
import org.rdfhdt.hdt.listener.ProgressListener;
import org.rdfhdt.hdt.options.ControlInfo;
import org.rdfhdt.hdt.options.HDTOptions;
import org.rdfhdt.hdt.options.HDTSpecification;
import org.rdfhdt.hdt.rdf.RDFParserCallback.RDFCallback;
import org.rdfhdt.hdt.rdf.parsers.RDFParserSimple;
import org.rdfhdt.hdt.triples.IteratorTripleString;
import org.rdfhdt.hdt.triples.TripleString;
import org.rdfhdt.hdt.util.io.IOUtil;

/**
 * @author mario.arias
 *
 */
public class PlainHeader implements HeaderPrivate, RDFCallback {
	
	protected HDTOptions spec;
	protected List<TripleString> triples= new ArrayList<TripleString>();
	
	public PlainHeader() {
		spec = new HDTSpecification();
	}
	
	public PlainHeader(HDTOptions spec) {
		this.spec = spec;
	}

	/* (non-Javadoc)
	 * @see hdt.rdf.RDFStorage#insert(java.lang.String, java.lang.String, java.lang.String)
	 */
	@Override
	public void insert(CharSequence subject, CharSequence predicate, CharSequence object) {
		String objStr = object.toString();
		if(objStr.charAt(0)=='<'|| objStr.charAt(0)=='"' || objStr.startsWith("http://")||objStr.startsWith("file://")) {
			triples.add(new TripleString(HeaderUtil.cleanURI(subject), HeaderUtil.cleanURI(predicate), object));
		} else {
			triples.add(new TripleString(HeaderUtil.cleanURI(subject), HeaderUtil.cleanURI(predicate), '"'+objStr+'"'));
		}
	}

	/* (non-Javadoc)
	 * @see hdt.rdf.RDFStorage#insert(java.lang.String, java.lang.String, long)
	 */
	@Override
	public void insert(CharSequence subject, CharSequence predicate, long object) {
		triples.add(new TripleString(HeaderUtil.cleanURI(subject), HeaderUtil.cleanURI(predicate), '"'+Long.toString(object)+'"'));
	}

	/* (non-Javadoc)
	 * @see hdt.header.Header#save(java.io.OutputStream, hdt.ControlInfo, hdt.ProgressListener)
	 */
	@Override
	public void save(OutputStream output, ControlInfo ci, ProgressListener listener) throws IOException {

		// Dump header into an array to calculate size and have it prepared.
		ByteArrayOutputStream headerData = new ByteArrayOutputStream();
		IteratorTripleString iterator = this.search("", "", "");
		while(iterator.hasNext()) {
			TripleString next = iterator.next();
			IOUtil.writeString(headerData, next.asNtriple().toString());
		}

		// Create ControlInfo
		ci.clear();
		ci.setType(ControlInfo.Type.HEADER);
		ci.setFormat(HDTVocabulary.HEADER_NTRIPLES);
		ci.setInt("length",headerData.size());
		ci.save(output);
		
		// Save Data
		output.write(headerData.toByteArray());
	}

	/* (non-Javadoc)
	 * @see hdt.header.Header#load(java.io.InputStream, hdt.ControlInfo, hdt.ProgressListener)
	 */
	@Override
	public void load(InputStream input, ControlInfo ci, ProgressListener listener) throws IOException {
		String format = ci.getFormat();
		if(!format.equals(HDTVocabulary.HEADER_NTRIPLES)) {
			// FIXME: Add support for other formats
			throw new IllegalArgumentException("Cannot parse this Header Format");
		}		
		
		long headerSize = ci.getInt("length");
		byte [] headerData = IOUtil.readBuffer(input, (int)headerSize, listener);
		
		try {
			RDFParserSimple parser = new RDFParserSimple();
			parser.doParse(new ByteArrayInputStream(headerData), "http://www.rdfhdt.org", RDFNotation.NTRIPLES, this);
		} catch (ParserException e) {
			e.printStackTrace();
			throw new IllegalFormatException("Error parsing header");
		}
	}

	/* (non-Javadoc)
	 * @see hdt.header.Header#getNumberOfElements()
	 */
	@Override
	public int getNumberOfElements() {
		return triples.size();
	}

	/* (non-Javadoc)
	 * @see hdt.header.Header#search(java.lang.String, java.lang.String, java.lang.String)
	 */
	@Override
	public IteratorTripleString search(CharSequence subject, CharSequence predicate, CharSequence object) {
		TripleString pattern = new TripleString(subject.toString(), predicate.toString(), object.toString());
		return new PlainHeaderIterator(this, pattern);
	}

	@Override
	public void processTriple(TripleString triple, long pos) {
		triples.add(new TripleString(triple));
	}

	@Override
	public void remove(CharSequence subject, CharSequence predicate, CharSequence object) {
		TripleString pattern = new TripleString(subject.toString(), predicate.toString(), object.toString());
		Iterator<TripleString> iter = triples.iterator();
		while(iter.hasNext()) {
			TripleString next = iter.next();
			if(next.match(pattern)) {
				iter.remove();
			}
		}
	}

	@Override
	public CharSequence getBaseURI() {
		IteratorTripleString it = search("", HDTVocabulary.RDF_TYPE, HDTVocabulary.HDT_DATASET);
		if(it.hasNext()) {
			TripleString ts = it.next();
			return ts.getSubject();
		}
		return "";
	}
}