Lucene example source code file (MultiCollectorTest.java)

This example Lucene source code file (MultiCollectorTest.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

collector, collector, dummycollector, dummycollector, exception, illegalargumentexception, io, ioexception, lucenetestcase, multicollector, multicollectortest, override, override, test, test

The Lucene MultiCollectorTest.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 org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.util.LuceneTestCase;
import org.junit.Test;

public class MultiCollectorTest extends LuceneTestCase {

  private static class DummyCollector extends Collector {

    boolean acceptsDocsOutOfOrderCalled = false;
    boolean collectCalled = false;
    boolean setNextReaderCalled = false;
    boolean setScorerCalled = false;

    @Override
    public boolean acceptsDocsOutOfOrder() {
      acceptsDocsOutOfOrderCalled = true;
      return true;
    }

    @Override
    public void collect(int doc) throws IOException {
      collectCalled = true;
    }

    @Override
    public void setNextReader(IndexReader reader, int docBase) throws IOException {
      setNextReaderCalled = true;
    }

    @Override
    public void setScorer(Scorer scorer) throws IOException {
      setScorerCalled = true;
    }

  }

  @Test
  public void testNullCollectors() throws Exception {
    // Tests that the collector rejects all null collectors.
    try {
      MultiCollector.wrap(null, null);
      fail("only null collectors should not be supported");
    } catch (IllegalArgumentException e) {
      // expected
    }

    // Tests that the collector handles some null collectors well. If it
    // doesn't, an NPE would be thrown.
    Collector c = MultiCollector.wrap(new DummyCollector(), null, new DummyCollector());
    assertTrue(c instanceof MultiCollector);
    assertTrue(c.acceptsDocsOutOfOrder());
    c.collect(1);
    c.setNextReader(null, 0);
    c.setScorer(null);
  }

  @Test
  public void testSingleCollector() throws Exception {
    // Tests that if a single Collector is input, it is returned (and not MultiCollector).
    DummyCollector dc = new DummyCollector();
    assertSame(dc, MultiCollector.wrap(dc));
    assertSame(dc, MultiCollector.wrap(dc, null));
  }
  
  @Test
  public void testCollector() throws Exception {
    // Tests that the collector delegates calls to input collectors properly.

    // Tests that the collector handles some null collectors well. If it
    // doesn't, an NPE would be thrown.
    DummyCollector[] dcs = new DummyCollector[] { new DummyCollector(), new DummyCollector() };
    Collector c = MultiCollector.wrap(dcs);
    assertTrue(c.acceptsDocsOutOfOrder());
    c.collect(1);
    c.setNextReader(null, 0);
    c.setScorer(null);

    for (DummyCollector dc : dcs) {
      assertTrue(dc.acceptsDocsOutOfOrderCalled);
      assertTrue(dc.collectCalled);
      assertTrue(dc.setNextReaderCalled);
      assertTrue(dc.setScorerCalled);
    }

  }

}