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Lucene example source code file (TestTimeLimitingCollector.java)

This example Lucene source code file (TestTimeLimitingCollector.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

bitset, collector, exception, exception, io, ioexception, myhitcollector, myhitcollector, override, override, slow_down, string, thread, time_allowed, time_allowed, util

The Lucene TestTimeLimitingCollector.java source code

package org.apache.lucene.search;

/**
 * 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.IOException;
import java.util.BitSet;

import org.apache.lucene.analysis.MockAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.RandomIndexWriter;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.TimeLimitingCollector.TimeExceededException;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util.ThreadInterruptedException;

/**
 * Tests the {@link TimeLimitingCollector}.  This test checks (1) search
 * correctness (regardless of timeout), (2) expected timeout behavior,
 * and (3) a sanity test with multiple searching threads.
 */
public class TestTimeLimitingCollector extends LuceneTestCase {
  private static final int SLOW_DOWN = 3;
  private static final long TIME_ALLOWED = 17 * SLOW_DOWN; // so searches can find about 17 docs.
  
  // max time allowed is relaxed for multithreading tests. 
  // the multithread case fails when setting this to 1 (no slack) and launching many threads (>2000).  
  // but this is not a real failure, just noise.
  private static final double MULTI_THREAD_SLACK = 7;      
            
  private static final int N_DOCS = 3000;
  private static final int N_THREADS = 50;

  private Searcher searcher;
  private Directory directory;
  private IndexReader reader;

  private final String FIELD_NAME = "body";
  private Query query;

  /**
   * initializes searcher with a document set
   */
  @Override
  public void setUp() throws Exception {
    super.setUp();
    final String docText[] = {
        "docThatNeverMatchesSoWeCanRequireLastDocCollectedToBeGreaterThanZero",
        "one blah three",
        "one foo three multiOne",
        "one foobar three multiThree",
        "blueberry pancakes",
        "blueberry pie",
        "blueberry strudel",
        "blueberry pizza",
    };
    directory = newDirectory();
    RandomIndexWriter iw = new RandomIndexWriter(random, directory, newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random)).setMergePolicy(newLogMergePolicy()));
    
    for (int i=0; i<N_DOCS; i++) {
      add(docText[i%docText.length], iw);
    }
    reader = iw.getReader();
    iw.close();
    searcher = newSearcher(reader);

    String qtxt = "one";
    // start from 1, so that the 0th doc never matches
    for (int i = 1; i < docText.length; i++) {
      qtxt += ' ' + docText[i]; // large query so that search will be longer
    }
    QueryParser queryParser = new QueryParser(TEST_VERSION_CURRENT, FIELD_NAME, new MockAnalyzer(random));
    query = queryParser.parse(qtxt);
    
    // warm the searcher
    searcher.search(query, null, 1000);

  }

  @Override
  public void tearDown() throws Exception {
    searcher.close();
    reader.close();
    directory.close();
    super.tearDown();
  }

  private void add(String value, RandomIndexWriter iw) throws IOException {
    Document d = new Document();
    d.add(newField(FIELD_NAME, value, Field.Store.NO, Field.Index.ANALYZED));
    iw.addDocument(d);
  }

  private void search(Collector collector) throws Exception {
    searcher.search(query, collector);
  }

  /**
   * test search correctness with no timeout
   */
  public void testSearch() {
    doTestSearch();
  }
  
  private void doTestSearch() {
    int totalResults = 0;
    int totalTLCResults = 0;
    try {
      MyHitCollector myHc = new MyHitCollector();
      search(myHc);
      totalResults = myHc.hitCount();
      
      myHc = new MyHitCollector();
      long oneHour = 3600000;
      Collector tlCollector = createTimedCollector(myHc, oneHour, false);
      search(tlCollector);
      totalTLCResults = myHc.hitCount();
    } catch (Exception e) {
      e.printStackTrace();
      assertTrue("Unexpected exception: "+e, false); //==fail
    }
    assertEquals( "Wrong number of results!", totalResults, totalTLCResults );
  }

  private Collector createTimedCollector(MyHitCollector hc, long timeAllowed, boolean greedy) {
    TimeLimitingCollector res = new TimeLimitingCollector(hc, timeAllowed);
    res.setGreedy(greedy); // set to true to make sure at least one doc is collected.
    return res;
  }

  /**
   * Test that timeout is obtained, and soon enough!
   */
  public void testTimeoutGreedy() {
    doTestTimeout(false, true);
  }
  
  /**
   * Test that timeout is obtained, and soon enough!
   */
  public void testTimeoutNotGreedy() {
    doTestTimeout(false, false);
  }

  private void doTestTimeout(boolean multiThreaded, boolean greedy) {
    // setup
    MyHitCollector myHc = new MyHitCollector();
    myHc.setSlowDown(SLOW_DOWN);
    Collector tlCollector = createTimedCollector(myHc, TIME_ALLOWED, greedy);

    // search
    TimeExceededException timoutException = null;
    try {
      search(tlCollector);
    } catch (TimeExceededException x) {
      timoutException = x;
    } catch (Exception e) {
      assertTrue("Unexpected exception: "+e, false); //==fail
    }
    
    // must get exception
    assertNotNull( "Timeout expected!", timoutException );

    // greediness affect last doc collected
    int exceptionDoc = timoutException.getLastDocCollected();
    int lastCollected = myHc.getLastDocCollected(); 
    assertTrue( "doc collected at timeout must be > 0!", exceptionDoc > 0 );
    if (greedy) {
      assertTrue("greedy="+greedy+" exceptionDoc="+exceptionDoc+" != lastCollected="+lastCollected, exceptionDoc==lastCollected);
      assertTrue("greedy, but no hits found!", myHc.hitCount() > 0 );
    } else {
      assertTrue("greedy="+greedy+" exceptionDoc="+exceptionDoc+" not > lastCollected="+lastCollected, exceptionDoc>lastCollected);
    }

    // verify that elapsed time at exception is within valid limits
    assertEquals( timoutException.getTimeAllowed(), TIME_ALLOWED);
    // a) Not too early
    assertTrue ( "elapsed="+timoutException.getTimeElapsed()+" <= (allowed-resolution)="+(TIME_ALLOWED-TimeLimitingCollector.getResolution()),
        timoutException.getTimeElapsed() > TIME_ALLOWED-TimeLimitingCollector.getResolution());
    // b) Not too late.
    //    This part is problematic in a busy test system, so we just print a warning.
    //    We already verified that a timeout occurred, we just can't be picky about how long it took.
    if (timoutException.getTimeElapsed() > maxTime(multiThreaded)) {
      System.out.println("Informative: timeout exceeded (no action required: most probably just " +
        " because the test machine is slower than usual):  " +
        "lastDoc="+exceptionDoc+
        " ,&& allowed="+timoutException.getTimeAllowed() +
        " ,&& elapsed="+timoutException.getTimeElapsed() +
        " >= " + maxTimeStr(multiThreaded));
    }
  }

  private long maxTime(boolean multiThreaded) {
    long res = 2 * TimeLimitingCollector.getResolution() + TIME_ALLOWED + SLOW_DOWN; // some slack for less noise in this test
    if (multiThreaded) {
      res *= MULTI_THREAD_SLACK; // larger slack  
    }
    return res;
  }

  private String maxTimeStr(boolean multiThreaded) {
    String s =
      "( " +
      "2*resolution +  TIME_ALLOWED + SLOW_DOWN = " +
      "2*" + TimeLimitingCollector.getResolution() + " + " + TIME_ALLOWED + " + " + SLOW_DOWN +
      ")";
    if (multiThreaded) {
      s = MULTI_THREAD_SLACK + " * "+s;  
    }
    return maxTime(multiThreaded) + " = " + s;
  }

  /**
   * Test timeout behavior when resolution is modified. 
   */
  public void testModifyResolution() {
    try {
      // increase and test
      long resolution = 20 * TimeLimitingCollector.DEFAULT_RESOLUTION; //400
      TimeLimitingCollector.setResolution(resolution);
      assertEquals(resolution, TimeLimitingCollector.getResolution());
      doTestTimeout(false,true);
      // decrease much and test
      resolution = 5;
      TimeLimitingCollector.setResolution(resolution);
      assertEquals(resolution, TimeLimitingCollector.getResolution());
      doTestTimeout(false,true);
      // return to default and test
      resolution = TimeLimitingCollector.DEFAULT_RESOLUTION;
      TimeLimitingCollector.setResolution(resolution);
      assertEquals(resolution, TimeLimitingCollector.getResolution());
      doTestTimeout(false,true);
    } finally {
      TimeLimitingCollector.setResolution(TimeLimitingCollector.DEFAULT_RESOLUTION);
    }
  }
  
  /** 
   * Test correctness with multiple searching threads.
   */
  public void testSearchMultiThreaded() throws Exception {
    doTestMultiThreads(false);
  }

  /** 
   * Test correctness with multiple searching threads.
   */
  public void testTimeoutMultiThreaded() throws Exception {
    doTestMultiThreads(true);
  }
  
  private void doTestMultiThreads(final boolean withTimeout) throws Exception {
    Thread [] threadArray = new Thread[N_THREADS];
    final BitSet success = new BitSet(N_THREADS);
    for( int i = 0; i < threadArray.length; ++i ) {
      final int num = i;
      threadArray[num] = new Thread() {
          @Override
          public void run() {
            if (withTimeout) {
              doTestTimeout(true,true);
            } else {
              doTestSearch();
            }
            synchronized(success) {
              success.set(num);
            }
          }
      };
    }
    for( int i = 0; i < threadArray.length; ++i ) {
      threadArray[i].start();
    }
    for( int i = 0; i < threadArray.length; ++i ) {
      threadArray[i].join();
    }
    assertEquals("some threads failed!", N_THREADS,success.cardinality());
  }
  
  // counting collector that can slow down at collect().
  private class MyHitCollector extends Collector {
    private final BitSet bits = new BitSet();
    private int slowdown = 0;
    private int lastDocCollected = -1;
    private int docBase = 0;

    /**
     * amount of time to wait on each collect to simulate a long iteration
     */
    public void setSlowDown( int milliseconds ) {
      slowdown = milliseconds;
    }
    
    public int hitCount() {
      return bits.cardinality();
    }

    public int getLastDocCollected() {
      return lastDocCollected;
    }

    @Override
    public void setScorer(Scorer scorer) throws IOException {
      // scorer is not needed
    }
    
    @Override
    public void collect(final int doc) throws IOException {
      int docId = doc + docBase;
      if( slowdown > 0 ) {
        try {
          Thread.sleep(slowdown);
        } catch (InterruptedException ie) {
          throw new ThreadInterruptedException(ie);
        }
      }
      assert docId >= 0: " base=" + docBase + " doc=" + doc;
      bits.set( docId );
      lastDocCollected = docId;
    }
    
    @Override
    public void setNextReader(IndexReader reader, int base) {
      docBase = base;
    }
    
    @Override
    public boolean acceptsDocsOutOfOrder() {
      return false;
    }

  }

}

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