Lucene example source code file (TestPriorityQueue.java)

This example Lucene source code file (TestPriorityQueue.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

exception, integer, integer, integerqueue, integerqueue, lucenetestcase, override, priorityqueue, priorityqueue, random, random_multiplier, testpriorityqueue, testpriorityqueue, util

The Lucene TestPriorityQueue.java source code

package org.apache.lucene.util;

/**
 * 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.util.Random;

public class TestPriorityQueue extends LuceneTestCase {

    private static class IntegerQueue extends PriorityQueue<Integer> {
        public IntegerQueue(int count) {
            super();
            initialize(count);
        }

        @Override
        protected boolean lessThan(Integer a, Integer b) {
            return (a < b);
        }
    }

    public void testPQ() throws Exception {
        testPQ(10000 * RANDOM_MULTIPLIER, random);
    }

    public static void testPQ(int count, Random gen) {
        PriorityQueue<Integer> pq = new IntegerQueue(count);
        int sum = 0, sum2 = 0;

        for (int i = 0; i < count; i++)
        {
            int next = gen.nextInt();
            sum += next;
            pq.add(next);
        }

        //      Date end = new Date();

        //      System.out.print(((float)(end.getTime()-start.getTime()) / count) * 1000);
        //      System.out.println(" microseconds/put");

        //      start = new Date();

        int last = Integer.MIN_VALUE;
        for (int i = 0; i < count; i++)
        {
            Integer next = pq.pop();
            assertTrue(next.intValue() >= last);
            last = next.intValue();
            sum2 += last;
        }

        assertEquals(sum, sum2);
        //      end = new Date();

        //      System.out.print(((float)(end.getTime()-start.getTime()) / count) * 1000);
        //      System.out.println(" microseconds/pop");
    }

    public void testClear() {
        PriorityQueue<Integer> pq = new IntegerQueue(3);
        pq.add(2);
        pq.add(3);
        pq.add(1);
        assertEquals(3, pq.size());
        pq.clear();
        assertEquals(0, pq.size());
    }
    
    public void testFixedSize() {
        PriorityQueue<Integer> pq = new IntegerQueue(3);
        pq.insertWithOverflow(2);
        pq.insertWithOverflow(3);
        pq.insertWithOverflow(1);
        pq.insertWithOverflow(5);
        pq.insertWithOverflow(7);
        pq.insertWithOverflow(1);
        assertEquals(3, pq.size());
        assertEquals((Integer) 3, pq.top());
    }
    
    public void testInsertWithOverflow() {
      int size = 4;
      PriorityQueue<Integer> pq = new IntegerQueue(size);
      Integer i1 = 2;
      Integer i2 = 3;
      Integer i3 = 1;
      Integer i4 = 5;
      Integer i5 = 7;
      Integer i6 = 1;
      
      assertNull(pq.insertWithOverflow(i1));
      assertNull(pq.insertWithOverflow(i2));
      assertNull(pq.insertWithOverflow(i3));
      assertNull(pq.insertWithOverflow(i4));
      assertTrue(pq.insertWithOverflow(i5) == i3); // i3 should have been dropped
      assertTrue(pq.insertWithOverflow(i6) == i6); // i6 should not have been inserted
      assertEquals(size, pq.size());
      assertEquals((Integer) 2, pq.top());
    }
  
}