// ReferenceIterator.java // (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany // first published 30.03.2008 on http://yacy.net // // This is a part of YaCy, a peer-to-peer based web search engine // // $LastChangedDate$ // $LastChangedRevision$ // $LastChangedBy$ // // 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 net.yacy.kelondro.rwi; import java.io.File; import java.io.IOException; import java.util.Map; import net.yacy.cora.document.encoding.UTF8; import net.yacy.cora.order.CloneableIterator; import net.yacy.cora.util.ConcurrentLog; import net.yacy.cora.util.LookAheadIterator; import net.yacy.cora.util.SpaceExceededException; import net.yacy.kelondro.blob.HeapReader; import net.yacy.kelondro.index.RowSet; /** * iterator of BLOBHeap files: is used to import heap dumps into a write-enabled index heap */ public class ReferenceIterator <ReferenceType extends Reference> extends LookAheadIterator<ReferenceContainer<ReferenceType>> implements CloneableIterator<ReferenceContainer<ReferenceType>>, Iterable<ReferenceContainer<ReferenceType>> { private HeapReader.entries blobs; private File blobFile; private ReferenceFactory<ReferenceType> factory; public ReferenceIterator(final File blobFile, final ReferenceFactory<ReferenceType> factory) throws IOException { this.blobs = new HeapReader.entries(blobFile, factory.getRow().primaryKeyLength); this.blobFile = blobFile; this.factory = factory; } /** * return an index container * because they may get very large, it is wise to deallocate some memory before calling next() */ @Override public ReferenceContainer<ReferenceType> next0() { if (this.blobs == null) return null; RowSet row; Map.Entry<byte[], byte[]> entry; while (this.blobs.hasNext()) { entry = this.blobs.next(); if (entry == null) break; try { row = RowSet.importRowSet(entry.getValue(), this.factory.getRow()); if (row == null) { ConcurrentLog.severe("ReferenceIterator", "lost entry '" + UTF8.String(entry.getKey()) + "' because importRowSet returned null"); continue; // thats a fail but not as REALLY bad if the whole method would crash here } return new ReferenceContainer<ReferenceType>(this.factory, entry.getKey(), row); } catch (final SpaceExceededException e) { ConcurrentLog.severe("ReferenceIterator", "lost entry '" + UTF8.String(entry.getKey()) + "' because of too low memory: " + e.toString()); continue; } catch (final Throwable e) { ConcurrentLog.severe("ReferenceIterator", "lost entry '" + UTF8.String(entry.getKey()) + "' because of error: " + e.toString()); continue; } } close(); return null; } @Override public synchronized void close() { if (this.blobs != null) this.blobs.close(); this.blobs = null; } @Override public CloneableIterator<ReferenceContainer<ReferenceType>> clone(final Object modifier) { if (this.blobs != null) this.blobs.close(); this.blobs = null; try { return new ReferenceIterator<ReferenceType>(this.blobFile, this.factory); } catch (final IOException e) { ConcurrentLog.logException(e); return null; } } }