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132 lines
4.5 KiB
132 lines
4.5 KiB
// kelondroBufferedEcoFS.java
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// (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
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// first published 14.01.2008 on http://yacy.net
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//
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// $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
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// $LastChangedRevision: 1986 $
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// $LastChangedBy: orbiter $
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//
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// LICENSE
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package de.anomic.kelondro;
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import java.io.File;
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import java.io.IOException;
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import java.util.Iterator;
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import java.util.Map;
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import java.util.TreeMap;
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/**
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* The kelondroBufferedEcoFS extends the IO reduction to EcoFS by providing a
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* write buffer to elements that are INSIDE the filed entries of the file
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* That means, each time, an entry is written to the end of the file, it is NOT buffered here,
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* but possibly buffered in the enclosed kelondroEcoFS
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*/
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public class kelondroBufferedEcoFS {
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private kelondroEcoFS efs;
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private final int maxEntries;
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private final TreeMap<Long, byte[]> buffer;
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public kelondroBufferedEcoFS(final kelondroEcoFS efs, final int maxEntries) {
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this.efs = efs;
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this.maxEntries = maxEntries;
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this.buffer = new TreeMap<Long, byte[]>();
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}
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private void flushBuffer() throws IOException {
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if (efs == null) return;
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final Iterator<Map.Entry<Long, byte[]>> i = buffer.entrySet().iterator();
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Map.Entry<Long, byte[]> entry;
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while (i.hasNext()) {
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entry = i.next();
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efs.put(entry.getKey().intValue(), entry.getValue(), 0);
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}
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buffer.clear();
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}
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public synchronized long size() throws IOException {
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return efs.size();
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}
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public File filename() {
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return efs.filename();
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}
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public synchronized void close() {
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try {
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flushBuffer();
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} catch (final IOException e) {
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e.printStackTrace();
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}
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if (efs != null) efs.close();
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efs = null;
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}
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protected synchronized void finalize() {
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if (this.efs != null) this.close();
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}
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public synchronized void get(final long index, final byte[] b, final int start) throws IOException {
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assert b.length - start >= efs.recordsize;
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if (index >= size()) throw new IndexOutOfBoundsException("kelondroBufferedEcoFS.get(" + index + ") outside bounds (" + this.size() + ")");
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final byte[] bb = buffer.get(Long.valueOf(index));
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if (bb == null) {
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efs.get(index, b, start);
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} else {
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System.arraycopy(bb, 0, b, start, efs.recordsize);
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}
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}
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public synchronized void put(final long index, final byte[] b, final int start) throws IOException {
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assert b.length - start >= efs.recordsize;
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final long s = size();
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if (index > s) throw new IndexOutOfBoundsException("kelondroBufferedEcoFS.put(" + index + ") outside bounds (" + this.size() + ")");
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if (index == s) {
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efs.add(b, start);
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} else {
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final byte[] bb = new byte[efs.recordsize];
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System.arraycopy(b, start, bb, 0, efs.recordsize);
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buffer.put(Long.valueOf(index), bb);
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if (buffer.size() > this.maxEntries) flushBuffer();
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}
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}
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public synchronized void add(final byte[] b, final int start) throws IOException {
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assert b.length - start >= efs.recordsize;
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// index == size() == efs.size();
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efs.add(b, start);
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}
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public synchronized void cleanLast(final byte[] b, final int start) throws IOException {
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assert b.length - start >= efs.recordsize;
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final byte[] bb = buffer.remove(Long.valueOf(size() - 1));
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if (bb == null) {
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efs.cleanLast(b, start);
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} else {
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System.arraycopy(bb, 0, b, start, efs.recordsize);
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efs.cleanLast();
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}
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}
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public synchronized void cleanLast() throws IOException {
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buffer.remove(Long.valueOf(size() - 1));
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efs.cleanLast();
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}
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}
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