com.xpn.xwiki.plugin.lucene.RemoteIndexesSearcher.java Source code

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Here is the source code for com.xpn.xwiki.plugin.lucene.RemoteIndexesSearcher.java

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/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package com.xpn.xwiki.plugin.lucene;

import org.apache.commons.lang.StringUtils;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.ParallelMultiSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Searchable;
import org.apache.lucene.search.Sort;

import java.io.IOException;
import java.rmi.Naming;
import java.util.HashMap;
import java.util.List;
import java.util.ArrayList;

public class RemoteIndexesSearcher {

    private static HashMap searcherCache = new HashMap();

    private final String SlaveList;

    public int slaveListLength;

    public static int currentSlaveListLength;

    public static String searcherName;

    public RemoteIndexesSearcher(String slavelist, String searcherName) {
        this.SlaveList = slavelist;
        this.searcherName = searcherName;
        setSlaveListLength(this.SlaveList);
        createSearcher(this.SlaveList);
        ReInstantiate reInstantiate = new ReInstantiate(this);
        reInstantiate.start();
    }

    private void setSlaveListLength(String slavelist) {
        String[] slaves = StringUtils.split(slavelist, ",");
        this.slaveListLength = slaves.length;
    }

    /**
    * search multiple remote index <strong> parallel  </strong>.
    */
    public Hits search(Query query, Sort sort) throws IOException {
        ParallelMultiSearcher searcher = (ParallelMultiSearcher) searcherCache.get(this.searcherName);

        if (searcher == null) {
            Searchable[] remoteSearchables = createRemoteSearchers(this.SlaveList);
            searcher = new ParallelMultiSearcher(remoteSearchables);
            searcherCache.put(this.searcherName, searcher);
        }

        Hits hits;

        try {
            hits = (sort == null) ? searcher.search(query) : searcher.search(query, sort);
        } catch (Exception e) {
            resetSearcher(this.searcherName);
            hits = search(query, sort);
        }
        return hits;

    }

    private void createSearcher(String SlaveList) {
        try {
            Searchable[] remoteSearchables = createRemoteSearchers(this.SlaveList);
            ParallelMultiSearcher searcher = new ParallelMultiSearcher(remoteSearchables);
            searcherCache.put(this.searcherName, searcher);
        } catch (Exception e) {
        }
    }

    /**
    * Creates Searchables over remotely available indexes.
    */
    private Searchable[] createRemoteSearchers(String slavelist) {
        String[] slaves = StringUtils.split(slavelist, ",");
        List<Searchable> remoteSearcherList = new ArrayList<Searchable>();
        int count = 0;
        for (int i = 0; i < slaves.length; i++) {
            try {
                remoteSearcherList.add(lookupRemote(slaves[i], "XWiki_LuceneMultiSearch"));
                count++;
            } catch (Exception e) {
            }
        }
        this.currentSlaveListLength = count;
        return remoteSearcherList.toArray(new Searchable[remoteSearcherList.size()]);
    }

    private Searchable lookupRemote(String IPandPort, String name) throws Exception {
        return (Searchable) Naming.lookup("//" + IPandPort + "/" + name);
    }

    /**
    * Redefines the searcher used in search().
    * Redefining search is required/called when one the remotely available is index is updated or one of the slave is down.
    */
    public void resetSearcher(String searcherName) {
        try {
            Searchable[] remoteSearchables = createRemoteSearchers(this.SlaveList);
            ParallelMultiSearcher searcher = new ParallelMultiSearcher(remoteSearchables);
            if (searcherCache.containsKey(((String) searcherName)))
                ((ParallelMultiSearcher) searcherCache.get(searcherName)).close();
            searcherCache.put(searcherName, searcher);
        } catch (Exception e) {
        }
    }

    /**
    * A Thread which Redefines the searcher for every 1 minute.
    */
    private class ReInstantiate extends Thread {
        private RemoteIndexesSearcher remoteIndexesSearcher;

        private final int resetSearcherInterval = 30;

        private int count = 0;

        public ReInstantiate(RemoteIndexesSearcher remoteIndexesSearcher) {
            this.remoteIndexesSearcher = remoteIndexesSearcher;
        }

        public void run() {
            while (true) {
                try {
                    Thread.sleep(this.resetSearcherInterval * 1000);
                    this.count++;
                    if (this.count == 10000)
                        this.count = 0;

                    //if( this.count % 2 ==1 )
                    if (this.remoteIndexesSearcher.currentSlaveListLength == this.remoteIndexesSearcher.slaveListLength) {
                        continue;
                    } else {
                        this.remoteIndexesSearcher.resetSearcher(this.remoteIndexesSearcher.searcherName);
                    }
                } catch (Exception e) {
                }
            }
        }
    }
}