PersistentSpanSet.java from gzz at Krugle

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/*
PersistentSpanSet.java
 *    
 *    Copyright (c) 2002, Tuomas Lukka
 *
 *    This file is part of Gzz.
 *    
 *    Gzz 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 of the License, or
 *    (at your option) any later version.
 *    
 *    Gzz 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 Gzz; if not, write to the Free
 *    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *    MA  02111-1307  USA
 *    
 *
 */
/*
 * Written by Marc Schiereck 
 */

package gzz.media.impl;
import gzz.mediaserver.*;
import gzz.media.*;
import java.util.*;   
import java.io.*;
import gzz.*;  
import gzz.mediaserver.storage.*;

public class PersistentSpanSet implements SpanSet {
String rcsid = "$Id: PersistentSpanSet.java,v 1.3 2003/02/21 20:02:50 tjl Exp $";

    public interface ObjectFormat {
	Object read(Reader r);
        Span readSpan(Reader r);
 
	void write(Writer w, Span s, Object o);
    }

    Map map = new HashMap();

    ObjectFormat format;

    Storer storer;

    class SpanAndObject {
        String id;

        List spans = new ArrayList();
        List objs = new ArrayList();

        void add(Span span, Object obj) {
            this.spans.add(span);
            this.objs.add(obj);
        }
    }

    public PersistentSpanSet(Storer storer, ObjectFormat format) {
	this.format = format;
        this.storer = storer;
    }

    public void addSpan(Span span, Object obj) {
        String id = span.getScrollBlock().getID();

	if (map.get(id) == null) {
            SpanAndObject sao = readSAO(id);
            if (sao == null) {
                sao = new SpanAndObject();
                sao.id = id;
            }

            sao.add(span,obj);
            map.put(id, sao);
        }
	else {
            ((SpanAndObject)map.get(id)).add(span,obj);
        }
    }

    public Collection overlaps(Span span) { 
        String id = span.getScrollBlock().getID();
        List res = new ArrayList();
        
        if (map.get(id) != null) {
            SpanAndObject sao = (SpanAndObject)map.get(id);

            for(int i=0;i<sao.spans.size();i++) {
		if(((Span)sao.spans.get(i)).intersects(span))
		    res.add(sao.objs.get(i));
            }
        }
        return res;
    }

    public Collection spans() {  
        Iterator iter = map.values().iterator();
        List res = new ArrayList();

        while(iter.hasNext()) {
            res.addAll(((SpanAndObject)iter.next()).spans);
        }

        return Collections.unmodifiableCollection(res);
    }

    public void write () throws IOException {
        Iterator iter = map.values().iterator();

        while(iter.hasNext()) {
            writeSAO((SpanAndObject)iter.next());   
        }
    }

    protected void writeSAO(SpanAndObject sao) throws IOException{
        Writer write = new OutputStreamWriter(storer.store("pss_"+sao.id));
        Iterator iter1, iter2;
     
        iter1 = sao.spans.iterator();
        iter2 = sao.objs.iterator();
   
        while(iter1.hasNext()) {
            format.write(write, (Span)iter1.next(),iter2.next());
        }
    }

    SpanAndObject readSAO(String id) {
	InputStream is;
        try {
            is = storer.retrieve("pss_"+id);
        } 
        catch(IOException e) {
            return null;
        }

        if(is == null)
            return new SpanAndObject();

	Reader reader = new InputStreamReader(is);
        SpanAndObject sao = new SpanAndObject();

        sao.id = id;

	Span span;
	Object object;

	System.out.println("my format is: "+format);
	while((span = format.readSpan(reader)) != null) {
	    object = format.read(reader);
            sao.add(span, object);
	}

        return sao;
    }
}
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