HashDictionarySection.java

/**
 * File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/dictionary/impl/section/HashDictionarySection.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.dictionary.impl.section;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import org.rdfhdt.hdt.dictionary.TempDictionarySection;
import org.rdfhdt.hdt.options.HDTOptions;
import org.rdfhdt.hdt.options.HDTSpecification;
import org.rdfhdt.hdt.util.string.CharSequenceComparator;
import org.rdfhdt.hdt.util.string.CompactString;

/**
 * @author mario.arias
 *
 */
public class HashDictionarySection implements TempDictionarySection {
	public static final int TYPE_INDEX = 1;

	private HashMap<CharSequence, Integer> map;
	private List<CharSequence> list;
	private int size;
	boolean sorted;
	
	/**
	 * 
	 */
	public HashDictionarySection() {
		this(new HDTSpecification());
	}
	
	public HashDictionarySection(HDTOptions spec) {
		map = new HashMap<CharSequence, Integer>();
		list = new ArrayList<CharSequence>();
		size=0;
	}
	
	/* (non-Javadoc)
	 * @see hdt.dictionary.DictionarySection#locate(java.lang.CharSequence)
	 */
	@Override
	public int locate(CharSequence s) {
		CompactString compact = new CompactString(s);
		Integer val = map.get(compact);
		if(val==null) {
			return 0;
		}
		return val.intValue();
	}

	/* (non-Javadoc)
	 * @see hdt.dictionary.DictionarySection#extract(int)
	 */
	@Override
	public CharSequence extract(int pos) {
		if(pos<=0) {
			return null;
		}
		return list.get(pos-1);
	}

	/* (non-Javadoc)
	 * @see hdt.dictionary.DictionarySection#size()
	 */
	@Override
	public long size() {
		return size;
	}

	/* (non-Javadoc)
	 * @see hdt.dictionary.DictionarySection#getNumberOfElements()
	 */
	@Override
	public int getNumberOfElements() {
		return list.size();
	}

	/* (non-Javadoc)
	 * @see hdt.dictionary.DictionarySection#getEntries()
	 */
	@Override
	public Iterator<? extends CharSequence> getSortedEntries() {
		if(!sorted) {
			return null;
		}
		return list.iterator();
	}
	
	@Override
	public Iterator<? extends CharSequence> getEntries() {
		return list.iterator();
	}

	public int add(CharSequence entry) {
		CharSequence compact = new CompactString(entry);
		Integer pos = map.get(compact);
		if(pos!=null) {
			// Found return existing ID.
			return pos;
		}
		
		// Not found, insert new
		list.add(compact);
		map.put(compact, list.size());
		
		size+=compact.length();
		sorted = false;
		
		return list.size();
	}

	public void remove(CharSequence seq) {
		map.remove(seq);
		sorted = false;
	}
	
	public void sort() {
		// Update list.
		list = new ArrayList<CharSequence>(map.size());
		for(CharSequence str : map.keySet()) {
			list.add(str);
		}
		
		// Sort list
		Collections.sort(list, new CharSequenceComparator());
		
		// Update map indexes
		for(int i=1;i<=getNumberOfElements();i++) {
			map.put(extract(i), i);
		}
		
		sorted = true;
	}
	
	@Override
	public boolean isSorted() {
		return sorted;
	}

	@Override
	public void clear() {
		list.clear();
		map.clear();
		size=0;
		sorted = false; //because if sorted won't be anymore
	}
	
	@Override
	public void close() throws IOException {
		map=null;
		list=null;
	}
}