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Lucene example source code file (NRTManagerReopenThread.java)

This example Lucene source code file (NRTManagerReopenThread.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

closeable, illegalargumentexception, interruptedexception, interruptedexception, io, ioexception, nrtmanager, nrtmanager, nrtmanagerreopenthread, nrtmanagerreopenthread, override, runtimeexception, runtimeexception, threadinterruptedexception, throwable

The Lucene NRTManagerReopenThread.java source code

package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.Closeable;
import java.io.IOException;

import org.apache.lucene.util.ThreadInterruptedException;

/**
 * Utility class that runs a reopen thread to periodically
 * reopen the NRT searchers in the provided {@link
 * NRTManager}.
 *
 * <p> Typical usage looks like this:
 *
 * <pre>
 *   ... open your own writer ...
 * 
 *   NRTManager manager = new NRTManager(writer);
 *
 *   // Refreshes searcher every 5 seconds when nobody is waiting, and up to 100 msec delay
 *   // when somebody is waiting:
 *   NRTManagerReopenThread reopenThread = new NRTManagerReopenThread(manager, 5.0, 0.1);
 *   reopenThread.setName("NRT Reopen Thread");
 *   reopenThread.setPriority(Math.min(Thread.currentThread().getPriority()+2, Thread.MAX_PRIORITY));
 *   reopenThread.setDaemon(true);
 *   reopenThread.start();
 * </pre>
 *
 * Then, for each incoming query, do this:
 *
 * <pre>
 *   // For each incoming query:
 *   IndexSearcher searcher = manager.get();
 *   try {
 *     // Use searcher to search...
 *   } finally {
 *     manager.release(searcher);
 *   }
 * </pre>
 *
 * You should make changes using the <code>NRTManager; if you later need to obtain
 * a searcher reflecting those changes:
 *
 * <pre>
 *   // ... or updateDocument, deleteDocuments, etc:
 *   long gen = manager.addDocument(...);
 *   
 *   // Returned searcher is guaranteed to reflect the just added document
 *   IndexSearcher searcher = manager.get(gen);
 *   try {
 *     // Use searcher to search...
 *   } finally {
 *     manager.release(searcher);
 *   }
 * </pre>
 *
 *
 * When you are done be sure to close both the manager and the reopen thrad:
 * <pre> 
 *   reopenThread.close();       
 *   manager.close();
 * </pre>
 */

public class NRTManagerReopenThread extends Thread implements NRTManager.WaitingListener, Closeable {
  private final NRTManager manager;
  private final long targetMaxStaleNS;
  private final long targetMinStaleNS;
  private boolean finish;
  private boolean waitingNeedsDeletes;
  private long waitingGen;

  /**
   * Create NRTManagerReopenThread, to periodically reopen the NRT searcher.
   *
   * @param targetMaxStaleSec Maximum time until a new
   *        reader must be opened; this sets the upper bound
   *        on how slowly reopens may occur
   *
   * @param targetMinStaleSec Mininum time until a new
   *        reader can be opened; this sets the lower bound
   *        on how quickly reopens may occur, when a caller
   *        is waiting for a specific indexing change to
   *        become visible.
   */

  public NRTManagerReopenThread(NRTManager manager, double targetMaxStaleSec, double targetMinStaleSec) {
    if (targetMaxStaleSec < targetMinStaleSec) {
      throw new IllegalArgumentException("targetMaxScaleSec (= " + targetMaxStaleSec + ") < targetMinStaleSec (=" + targetMinStaleSec + ")");
    }
    this.manager = manager;
    this.targetMaxStaleNS = (long) (1000000000*targetMaxStaleSec);
    this.targetMinStaleNS = (long) (1000000000*targetMinStaleSec);
    manager.addWaitingListener(this);
  }

  public synchronized void close() {
    //System.out.println("NRT: set finish");
    manager.removeWaitingListener(this);
    this.finish = true;
    notify();
    try {
      join();
    } catch (InterruptedException ie) {
      throw new ThreadInterruptedException(ie);
    }
  }

  public synchronized void waiting(boolean needsDeletes, long targetGen) {
    waitingNeedsDeletes |= needsDeletes;
    waitingGen = Math.max(waitingGen, targetGen);
    notify();
    //System.out.println(Thread.currentThread().getName() + ": force wakeup waitingGen=" + waitingGen + " applyDeletes=" + applyDeletes + " waitingNeedsDeletes=" + waitingNeedsDeletes);
  }

  @Override
    public void run() {
    // TODO: maybe use private thread ticktock timer, in
    // case clock shift messes up nanoTime?
    long lastReopenStartNS = System.nanoTime();

    //System.out.println("reopen: start");
    try {
      while (true) {

        final boolean doApplyDeletes;

        boolean hasWaiting = false;

        synchronized(this) {
          // TODO: try to guestimate how long reopen might
          // take based on past data?

          while (!finish) {
            //System.out.println("reopen: cycle");

            // True if we have someone waiting for reopen'd searcher:
            hasWaiting = waitingGen > manager.getCurrentSearchingGen(waitingNeedsDeletes);
            final long nextReopenStartNS = lastReopenStartNS + (hasWaiting ? targetMinStaleNS : targetMaxStaleNS);

            final long sleepNS = nextReopenStartNS - System.nanoTime();

            if (sleepNS > 0) {
              //System.out.println("reopen: sleep " + (sleepNS/1000000.0) + " ms (hasWaiting=" + hasWaiting + ")");
              try {
                wait(sleepNS/1000000, (int) (sleepNS%1000000));
              } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
                //System.out.println("NRT: set finish on interrupt");
                finish = true;
                break;
              }
            } else {
              break;
            }
          }

          if (finish) {
            //System.out.println("reopen: finish");
            return;
          }

          doApplyDeletes = hasWaiting ? waitingNeedsDeletes : true;
          waitingNeedsDeletes = false;
          //System.out.println("reopen: start hasWaiting=" + hasWaiting);
        }

        lastReopenStartNS = System.nanoTime();
        try {
          //final long t0 = System.nanoTime();
          manager.reopen(doApplyDeletes);
          //System.out.println("reopen took " + ((System.nanoTime()-t0)/1000000.0) + " msec");
        } catch (IOException ioe) {
          //System.out.println(Thread.currentThread().getName() + ": IOE");
          //ioe.printStackTrace();
          throw new RuntimeException(ioe);
        }
      }
    } catch (Throwable t) {
      //System.out.println("REOPEN EXC");
      //t.printStackTrace(System.out);
      throw new RuntimeException(t);
    }
  }
}

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