- removed a memory overhead in collections which prevent OOM Exception in low memory configurations git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@5443 6c8d7289-2bf4-0310-a012-ef5d649a1542pull/1/head
orbiter
16 years ago
parent
5ce9d81955
commit
6c7e83909b
@ -0,0 +1,193 @@
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// indexContainerBLOBHeap.java
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// (C) 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
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// first published 04.01.2009 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: 2008-03-14 01:16:04 +0100 (Fr, 14 Mrz 2008) $
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// $LastChangedRevision: 4558 $
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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.index;
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import java.io.File;
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import java.io.IOException;
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import java.util.Date;
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import java.util.Iterator;
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import java.util.List;
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import de.anomic.kelondro.kelondroBLOBArray;
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import de.anomic.kelondro.kelondroCloneableIterator;
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import de.anomic.kelondro.kelondroRow;
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import de.anomic.kelondro.kelondroRowSet;
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public final class indexContainerBLOBHeap {
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private final kelondroRow payloadrow;
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private final kelondroBLOBArray array;
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/**
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* open a index container based on a BLOB dump. The content of the BLOB will not be read
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* unless a .idx file exists. Only the .idx file is opened to get a fast read access to
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* the BLOB. This class provides no write methods, because BLOB files should not be
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* written in random access. To support deletion, a write access to the BLOB for deletion
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* is still possible
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* @param payloadrow
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* @param log
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* @throws IOException
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*/
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public indexContainerBLOBHeap(
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final File heapLocation,
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final String blobSalt,
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final kelondroRow payloadrow) throws IOException {
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this.payloadrow = payloadrow;
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this.array = new kelondroBLOBArray(
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heapLocation,
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blobSalt,
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payloadrow.primaryKeyLength,
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payloadrow.getOrdering(),
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0);
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}
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public void close() {
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this.array.close();
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}
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public void clear() throws IOException {
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this.array.clear();
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}
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public int size() {
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return (this.array == null) ? 0 : this.array.size();
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}
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public File newContainerBLOBFile() {
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return this.array.newBLOB(new Date());
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}
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/**
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* return an iterator object that creates top-level-clones of the indexContainers
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* in the cache, so that manipulations of the iterated objects do not change
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* objects in the cache.
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* @throws IOException
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*/
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public synchronized kelondroCloneableIterator<indexContainer> wordContainers(final String startWordHash, final boolean rot) throws IOException {
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return new heapCacheIterator(startWordHash, rot);
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}
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/**
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* cache iterator: iterates objects within the heap cache. This can only be used
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* for write-enabled heaps, read-only heaps do not have a heap cache
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*/
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public class heapCacheIterator implements kelondroCloneableIterator<indexContainer>, Iterable<indexContainer> {
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// this class exists, because the wCache cannot be iterated with rotation
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// and because every indexContainer Object that is iterated must be returned as top-level-clone
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// so this class simulates wCache.tailMap(startWordHash).values().iterator()
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// plus the mentioned features
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private final boolean rot;
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private kelondroCloneableIterator<byte[]> iterator;
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public heapCacheIterator(final String startWordHash, final boolean rot) throws IOException {
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this.rot = rot;
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this.iterator = array.keys(true, startWordHash.getBytes());
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// The collection's iterator will return the values in the order that their corresponding keys appear in the tree.
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}
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public heapCacheIterator clone(final Object secondWordHash) {
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try {
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return new heapCacheIterator((String) secondWordHash, rot);
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} catch (IOException e) {
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e.printStackTrace();
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return null;
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}
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}
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public boolean hasNext() {
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if (rot) return true;
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return iterator.hasNext();
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}
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public indexContainer next() {
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try {
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if (iterator.hasNext()) {
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return get(new String(iterator.next()));
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}
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// rotation iteration
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if (!rot) {
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return null;
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}
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iterator = array.keys(true, null);
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return get(new String(iterator.next()));
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} catch (IOException e) {
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e.printStackTrace();
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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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iterator.remove();
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}
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public Iterator<indexContainer> iterator() {
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return this;
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}
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}
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/**
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* test if a given key is in the heap
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* this works with heaps in write- and read-mode
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* @param key
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* @return true, if the key is used in the heap; false othervise
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* @throws IOException
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*/
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public boolean has(final String key) {
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return this.array.has(key.getBytes());
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}
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/**
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* get a indexContainer from a heap
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* @param key
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* @return the indexContainer if one exist, null otherwise
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* @throws IOException
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*/
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public indexContainer get(final String key) throws IOException {
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List<byte[]> entries = this.array.getAll(key.getBytes());
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if (entries == null || entries.size() == 0) return null;
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byte[] a = entries.remove(0);
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indexContainer c = new indexContainer(key, kelondroRowSet.importRowSet(a, payloadrow));
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while (entries.size() > 0) {
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c = c.merge(new indexContainer(key, kelondroRowSet.importRowSet(entries.remove(0), payloadrow)));
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}
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return c;
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}
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/**
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* delete a indexContainer from the heap cache. This can only be used for write-enabled heaps
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* @param wordHash
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* @return the indexContainer if the cache contained the container, null othervise
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* @throws IOException
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*/
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public synchronized void delete(final String wordHash) throws IOException {
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// returns the index that had been deleted
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array.remove(wordHash.getBytes());
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}
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}
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// kelondroBLOBHeapModifier.java
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// (C) 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
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// first published 05.01.2009 on http://yacy.net
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//
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// $LastChangedDate: 2008-03-14 01:16:04 +0100 (Fr, 14 Mrz 2008) $
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// $LastChangedRevision: 4558 $
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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.SortedMap;
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import de.anomic.server.logging.serverLog;
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public class kelondroBLOBHeapModifier extends kelondroBLOBHeapReader implements kelondroBLOB {
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/*
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* This class adds a remove operation to a BLOBHeapReader
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*/
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/**
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* create a heap file: a arbitrary number of BLOBs, indexed by an access key
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* The heap file will be indexed upon initialization.
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* @param heapFile
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* @param keylength
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* @param ordering
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* @throws IOException
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*/
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public kelondroBLOBHeapModifier(final File heapFile, final int keylength, final kelondroByteOrder ordering) throws IOException {
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super(heapFile, keylength, ordering);
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mergeFreeEntries();
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}
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private void mergeFreeEntries() throws IOException {
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// try to merge free entries
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if (super.free.size() > 1) {
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int merged = 0;
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Map.Entry<Long, Integer> lastFree, nextFree;
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final Iterator<Map.Entry<Long, Integer>> i = this.free.entrySet().iterator();
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lastFree = i.next();
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while (i.hasNext()) {
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nextFree = i.next();
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//System.out.println("*** DEBUG BLOB: free-seek = " + nextFree.seek + ", size = " + nextFree.size);
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// check if they follow directly
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if (lastFree.getKey() + lastFree.getValue() + 4 == nextFree.getKey()) {
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// merge those records
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this.file.seek(lastFree.getKey());
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lastFree.setValue(lastFree.getValue() + nextFree.getValue() + 4); // this updates also the free map
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this.file.writeInt(lastFree.getValue());
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this.file.seek(nextFree.getKey());
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this.file.writeInt(0);
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i.remove();
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merged++;
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} else {
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lastFree = nextFree;
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}
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}
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serverLog.logInfo("kelondroBLOBHeap", "BLOB " + heapFile.getName() + ": merged " + merged + " free records");
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}
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}
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/**
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* clears the content of the database
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* @throws IOException
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*/
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public synchronized void clear() throws IOException {
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this.index.clear();
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this.free.clear();
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try {
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this.file.close();
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} catch (final IOException e) {
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e.printStackTrace();
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}
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this.heapFile.delete();
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this.file = new kelondroCachedFileRA(heapFile);
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}
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/**
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* close the BLOB table
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*/
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public synchronized void close() {
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shrinkWithGapsAtEnd();
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if (file != null) {
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try {
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file.close();
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} catch (final IOException e) {
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e.printStackTrace();
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}
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}
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file = null;
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if (index != null && free != null && (index.size() > 3 || free.size() > 3)) {
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// now we can create a dump of the index and the gap information
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// to speed up the next start
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try {
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long start = System.currentTimeMillis();
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free.dump(kelondroBLOBHeapWriter.fingerprintGapFile(this.heapFile));
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free.clear();
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free = null;
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index.dump(kelondroBLOBHeapWriter.fingerprintIndexFile(this.heapFile));
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serverLog.logInfo("kelondroBLOBHeap", "wrote a dump for the " + this.index.size() + " index entries of " + heapFile.getName()+ " in " + (System.currentTimeMillis() - start) + " milliseconds.");
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index.close();
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index = null;
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} catch (IOException e) {
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e.printStackTrace();
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}
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} else {
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// this is small.. just free resources, do not write index
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free.clear();
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free = null;
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index.close();
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index = null;
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}
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}
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/**
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* remove a BLOB
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* @param key the primary key
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* @throws IOException
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*/
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public synchronized void remove(final byte[] key) throws IOException {
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assert index.row().primaryKeyLength == key.length : index.row().primaryKeyLength + "!=" + key.length;
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// check if the index contains the key
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final long seek = index.getl(key);
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if (seek < 0) return;
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// access the file and read the container
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this.file.seek(seek);
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int size = file.readInt();
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//assert seek + size + 4 <= this.file.length() : heapFile.getName() + ": too long size " + size + " in record at " + seek;
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long filelength = this.file.length(); // put in separate variable for debugging
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if (seek + size + 4 > filelength) {
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serverLog.logSevere("BLOBHeap", heapFile.getName() + ": too long size " + size + " in record at " + seek);
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throw new IOException(heapFile.getName() + ": too long size " + size + " in record at " + seek);
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}
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// add entry to free array
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this.free.put(seek, size);
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// fill zeros to the content
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int l = size; byte[] fill = new byte[size];
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while (l-- > 0) fill[l] = 0;
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this.file.write(fill, 0, size);
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// remove entry from index
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this.index.removel(key);
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// recursively merge gaps
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tryMergeNextGaps(seek, size);
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tryMergePreviousGap(seek);
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}
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private void tryMergePreviousGap(final long thisSeek) throws IOException {
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// this is called after a record has been removed. That may cause that a new
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// empty record was surrounded by gaps. We merge with a previous gap, if this
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// is also empty, but don't do that recursively
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// If this is successful, it removes the given marker for thisSeed and
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// because of this, this method MUST be called AFTER tryMergeNextGaps was called.
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// first find the gap entry for the closest gap in front of the give gap
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SortedMap<Long, Integer> head = this.free.headMap(thisSeek);
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if (head.size() == 0) return;
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long previousSeek = head.lastKey().longValue();
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int previousSize = head.get(previousSeek).intValue();
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// check if this is directly in front
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if (previousSeek + previousSize + 4 == thisSeek) {
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// right in front! merge the gaps
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Integer thisSize = this.free.get(thisSeek);
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assert thisSize != null;
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mergeGaps(previousSeek, previousSize, thisSeek, thisSize.intValue());
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}
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}
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private void tryMergeNextGaps(final long thisSeek, final int thisSize) throws IOException {
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// try to merge two gaps if one gap has been processed already and the position of the next record is known
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// if the next record is also a gap, merge these gaps and go on recursively
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// first check if next gap position is outside of file size
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long nextSeek = thisSeek + thisSize + 4;
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if (nextSeek >= this.file.length()) return; // end of recursion
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// move to next position and read record size
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Integer nextSize = this.free.get(nextSeek);
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if (nextSize == null) return; // finished, this is not a gap
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// check if the record is a gap-record
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assert nextSize.intValue() > 0;
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if (nextSize.intValue() == 0) {
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// a strange gap record: we can extend the thisGap with four bytes
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// the nextRecord is a gap record; we remove that from the free list because it will be joined with the current gap
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mergeGaps(thisSeek, thisSize, nextSeek, 0);
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// recursively go on
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tryMergeNextGaps(thisSeek, thisSize + 4);
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} else {
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// check if this is a true gap!
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this.file.seek(nextSeek + 4);
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byte[] o = new byte[1];
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this.file.readFully(o, 0, 1);
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int t = o[0];
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assert t == 0;
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if (t == 0) {
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// the nextRecord is a gap record; we remove that from the free list because it will be joined with the current gap
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mergeGaps(thisSeek, thisSize, nextSeek, nextSize.intValue());
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// recursively go on
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tryMergeNextGaps(thisSeek, thisSize + 4 + nextSize.intValue());
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}
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}
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}
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private void mergeGaps(final long seek0, final int size0, final long seek1, final int size1) throws IOException {
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//System.out.println("*** DEBUG-BLOBHeap " + heapFile.getName() + ": merging gap from pos " + seek0 + ", len " + size0 + " with next record of size " + size1 + " (+ 4)");
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Integer g = this.free.remove(seek1); // g is only used for debugging
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assert g != null;
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||||
assert g.intValue() == size1;
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// overwrite the size bytes of next records with zeros
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this.file.seek(seek1);
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this.file.writeInt(0);
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// the new size of the current gap: old size + len + 4
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int newSize = size0 + 4 + size1;
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this.file.seek(seek0);
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this.file.writeInt(newSize);
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// register new gap in the free array; overwrite old gap entry
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g = this.free.put(seek0, newSize);
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assert g != null;
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assert g.intValue() == size0;
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}
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protected void shrinkWithGapsAtEnd() {
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// find gaps at the end of the file and shrink the file by these gaps
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||||
try {
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||||
while (this.free.size() > 0) {
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Long seek = this.free.lastKey();
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||||
int size = this.free.get(seek).intValue();
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||||
if (seek.longValue() + size + 4 != this.file.length()) return;
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||||
// shrink the file
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this.file.setLength(seek.longValue());
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this.free.remove(seek);
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||||
}
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||||
} catch (IOException e) {
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e.printStackTrace();
|
||||
}
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||||
}
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||||
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||||
public void put(byte[] key, byte[] b) throws IOException {
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throw new UnsupportedOperationException("put is not supported in BLOBHeapModifier");
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}
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}
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||||
Loading…
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