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Lucene example source code file (TestCollectionUtil.java)

This example Lucene source code file (TestCollectionUtil.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

arraylist, arraylist, integer, linkedlist, linkedlist, list, list, lucenetestcase, random_multiplier, random_multiplier, testcollectionutil, util

The Lucene TestCollectionUtil.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.Arrays;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class TestCollectionUtil extends LuceneTestCase {

  private List<Integer> createRandomList(int maxSize) {
    final Integer[] a = new Integer[random.nextInt(maxSize) + 1];
    for (int i = 0; i < a.length; i++) {
      a[i] = Integer.valueOf(random.nextInt(a.length));
    }
    return Arrays.asList(a);
  }
  
  public void testQuickSort() {
    for (int i = 0, c = 500 * RANDOM_MULTIPLIER; i < c; i++) {
      List<Integer> list1 = createRandomList(1000), list2 = new ArrayList(list1);
      CollectionUtil.quickSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
      
      list1 = createRandomList(1000);
      list2 = new ArrayList<Integer>(list1);
      CollectionUtil.quickSort(list1, Collections.reverseOrder());
      Collections.sort(list2, Collections.reverseOrder());
      assertEquals(list2, list1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      CollectionUtil.quickSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
    }
  }
  
  public void testMergeSort() {
    for (int i = 0, c = 500 * RANDOM_MULTIPLIER; i < c; i++) {
      List<Integer> list1 = createRandomList(1000), list2 = new ArrayList(list1);
      CollectionUtil.mergeSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
      
      list1 = createRandomList(1000);
      list2 = new ArrayList<Integer>(list1);
      CollectionUtil.mergeSort(list1, Collections.reverseOrder());
      Collections.sort(list2, Collections.reverseOrder());
      assertEquals(list2, list1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      CollectionUtil.mergeSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
    }
  }
  
  public void testInsertionSort() {
    for (int i = 0, c = 500 * RANDOM_MULTIPLIER; i < c; i++) {
      List<Integer> list1 = createRandomList(30), list2 = new ArrayList(list1);
      CollectionUtil.insertionSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
      
      list1 = createRandomList(30);
      list2 = new ArrayList<Integer>(list1);
      CollectionUtil.insertionSort(list1, Collections.reverseOrder());
      Collections.sort(list2, Collections.reverseOrder());
      assertEquals(list2, list1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      CollectionUtil.insertionSort(list1);
      Collections.sort(list2);
      assertEquals(list2, list1);
    }
  }
  
  public void testEmptyListSort() {
    // should produce no exceptions
    List<Integer> list = Arrays.asList(new Integer[0]);
    CollectionUtil.quickSort(list);
    CollectionUtil.mergeSort(list);
    CollectionUtil.insertionSort(list);
    CollectionUtil.quickSort(list, Collections.reverseOrder());
    CollectionUtil.mergeSort(list, Collections.reverseOrder());
    CollectionUtil.insertionSort(list, Collections.reverseOrder());
    
    // check that empty non-random access lists pass sorting without ex (as sorting is not needed)
    list = new LinkedList<Integer>();
    CollectionUtil.quickSort(list);
    CollectionUtil.mergeSort(list);
    CollectionUtil.insertionSort(list);
    CollectionUtil.quickSort(list, Collections.reverseOrder());
    CollectionUtil.mergeSort(list, Collections.reverseOrder());
    CollectionUtil.insertionSort(list, Collections.reverseOrder());
  }
  
  public void testOneElementListSort() {
    // check that one-element non-random access lists pass sorting without ex (as sorting is not needed)
    List<Integer> list = new LinkedList();
    list.add(1);
    CollectionUtil.quickSort(list);
    CollectionUtil.mergeSort(list);
    CollectionUtil.insertionSort(list);
    CollectionUtil.quickSort(list, Collections.reverseOrder());
    CollectionUtil.mergeSort(list, Collections.reverseOrder());
    CollectionUtil.insertionSort(list, Collections.reverseOrder());
  }
  
}

Other Lucene examples (source code examples)

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