yacy_search_server/source/de/anomic/kelondro/kelondroRowBufferedSet.java

// kelondroRowBufferedSet.java
// (C) 2006 by Michael Peter Christen; mc@anomic.de, Frankfurt a. M., Germany
// first published 21.06.2006 on http://www.anomic.de
//
// $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
// $LastChangedRevision: 1986 $
// $LastChangedBy: orbiter $
//
// LICENSE
// 
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package de.anomic.kelondro;

import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.TreeMap;

import de.anomic.server.serverMemory;

public class kelondroRowBufferedSet extends kelondroRowSet {

    private static final long memBlockLimit = 2000000;      // do not fill cache further if the amount of available memory is less that this
    private static final int bufferFlushLimit = 10000;
    private static final int bufferFlushMinimum = 1000; 
    private final boolean useRowCollection = true;
    private kelondroProfile profile;
    private TreeMap buffer;

    public kelondroRowBufferedSet(kelondroRow rowdef) {
        super(rowdef);
        buffer = new TreeMap(kelondroNaturalOrder.naturalOrder);
        profile = new kelondroProfile();
    }

    public kelondroRowBufferedSet(kelondroRow rowdef, int objectCount) {
        super(rowdef, objectCount);
        buffer = new TreeMap(kelondroNaturalOrder.naturalOrder);
        profile = new kelondroProfile();
    }
    
    private final void flush() {
        // call only in synchronized environment
        Iterator i = buffer.entrySet().iterator();
        Map.Entry entry;
        while (i.hasNext()) {
            entry = (Map.Entry) i.next();
            super.add((kelondroRow.Entry) entry.getValue());
        }
        buffer.clear();
    }
    
    public final void trim() {
        synchronized (buffer) {
            flush();
            super.trim();
        }
    }
    
    public void removeOne() {
        synchronized (buffer) {
            if (buffer.size() == 0) {
                super.removeOne();
            } else try {
                //buffer.remove(buffer.keySet().iterator().next());
                buffer.remove(buffer.lastKey());
            } catch (NoSuchElementException e) {}
        }
    }
    
    public void clear() {
        synchronized (buffer) {
            super.clear();
            buffer.clear();
        }
    }
    
    public int size() {
        synchronized (buffer) {
            return buffer.size() + super.size();
        }
    }
    
    public Iterator rows() {
        synchronized (buffer) {
            flush();
        }
        return super.rows();
    }
    
    public void uniq() {
        synchronized (buffer) {
            flush();
            super.uniq();
        }
    }
    
    public String toString() {
        synchronized (buffer) {
            flush();
            return super.toString();
        }
    }
    
    public kelondroRow.Entry get(byte[] key) {
        long handle = profile.startRead();
        kelondroRow.Entry entry = null;
        synchronized (buffer) {
            entry = (kelondroRow.Entry) buffer.get(key);
            if ((entry == null) && (useRowCollection)) entry = super.get(key);
        }
        profile.stopRead(handle);
        return entry;
    }
    
    public kelondroRow.Entry put(kelondroRow.Entry newentry) {
        long handle = profile.startWrite();
        byte[] key = newentry.getColBytes(super.sortColumn);
        kelondroRow.Entry oldentry = null;
        synchronized (buffer) {
            if (useRowCollection) {
                oldentry = (kelondroRow.Entry) buffer.get(key);
                if (oldentry == null) {
                    // try the collection
                    oldentry = super.get(key);
                    if (oldentry == null) {
                        // this was not anywhere
                        buffer.put(key, newentry);
                        if (((buffer.size() > bufferFlushMinimum) &&  (serverMemory.available() > memBlockLimit)) ||
                            (buffer.size() > bufferFlushLimit)) flush();
                    } else {
                        // replace old entry
                        super.put(newentry);
                    }
                } else {
                    // the entry is already in buffer
                    // simply replace old entry
                    buffer.put(key, newentry);
                }
            } else {
                oldentry = (kelondroRow.Entry) buffer.put(key, newentry);
            }
        }
        profile.stopWrite(handle);
        return oldentry;
    }
    
    public kelondroRow.Entry removeShift(byte[] key) {
        long handle = profile.startDelete();
        kelondroRow.Entry oldentry = null;
        synchronized (buffer) {
            oldentry = (kelondroRow.Entry) buffer.remove(key);
            if ((oldentry == null) && (useRowCollection)) {
                // try the collection
                oldentry = super.removeShift(key);
            }
        }
        profile.stopDelete(handle);
        return oldentry;
    }
    
    public kelondroRow.Entry removeMarked(byte[] key) {
        long handle = profile.startDelete();
        kelondroRow.Entry oldentry = null;
        synchronized (buffer) {
            oldentry = (kelondroRow.Entry) buffer.remove(key);
            if ((oldentry == null) && (useRowCollection)) {
                // try the collection
                return super.removeMarked(key);
            }
        }
        profile.stopDelete(handle);
        return oldentry;
    }
    
    public void removeMarkedAll(kelondroRowCollection c) {
        long handle = profile.startDelete();
        synchronized (buffer) {
            flush();
            super.removeMarkedAll(c);
        }
        profile.stopDelete(handle);
    }

    public kelondroProfile profile() {
        return profile;
    }
    
}