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102 lines
3.6 KiB
102 lines
3.6 KiB
// ReferenceIterator.java
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// (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
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// first published 30.03.2008 on http://yacy.net
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//
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// This is a part of YaCy, a peer-to-peer based web search engine
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//
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// $LastChangedDate$
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// $LastChangedRevision$
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// $LastChangedBy$
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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 net.yacy.kelondro.rwi;
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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 net.yacy.kelondro.blob.HeapReader;
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import net.yacy.kelondro.index.Row;
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import net.yacy.kelondro.index.RowSet;
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import net.yacy.kelondro.index.RowSpaceExceededException;
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import net.yacy.kelondro.logging.Log;
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import net.yacy.kelondro.order.CloneableIterator;
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/**
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* iterator of BLOBHeap files: is used to import heap dumps into a write-enabled index heap
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*/
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public class ReferenceIterator <ReferenceType extends Reference> implements CloneableIterator<ReferenceContainer<ReferenceType>>, Iterable<ReferenceContainer<ReferenceType>> {
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HeapReader.entries blobs;
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Row payloadrow;
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File blobFile;
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ReferenceFactory<ReferenceType> factory;
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public ReferenceIterator(final File blobFile, ReferenceFactory<ReferenceType> factory, final Row payloadrow) throws IOException {
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this.blobs = new HeapReader.entries(blobFile, payloadrow.primaryKeyLength);
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this.payloadrow = payloadrow;
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this.blobFile = blobFile;
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this.factory = factory;
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}
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public boolean hasNext() {
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if (blobs == null) return false;
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if (blobs.hasNext()) return true;
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close();
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return false;
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}
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/**
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* return an index container
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* because they may get very large, it is wise to deallocate some memory before calling next()
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*/
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public ReferenceContainer<ReferenceType> next() {
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Map.Entry<byte[], byte[]> entry = blobs.next();
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byte[] payload = entry.getValue();
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try {
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return new ReferenceContainer<ReferenceType>(factory, entry.getKey(), RowSet.importRowSet(payload, payloadrow));
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} catch (RowSpaceExceededException e) {
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Log.logSevere("ReferenceIterator", "lost entry '" + entry.getKey() + "' because of too low memory: " + e.toString());
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return null;
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}
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}
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public void remove() {
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throw new UnsupportedOperationException("heap dumps are read-only");
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}
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public Iterator<ReferenceContainer<ReferenceType>> iterator() {
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return this;
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}
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public void close() {
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if (blobs != null) this.blobs.close();
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blobs = null;
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}
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public CloneableIterator<ReferenceContainer<ReferenceType>> clone(Object modifier) {
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if (blobs != null) this.blobs.close();
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blobs = null;
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try {
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return new ReferenceIterator<ReferenceType>(this.blobFile, factory, this.payloadrow);
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} catch (IOException e) {
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Log.logException(e);
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return null;
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}
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}
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} |