Lucene example source code file (TestArrayUtil.java)

This example Lucene source code file (TestArrayUtil.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

comparable, comparable, exception, integer, integer, item, item, lucenetestcase, numberformatexception, numberformatexception, override, string, testarrayutil, util

The Lucene TestArrayUtil.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.Collections;

public class TestArrayUtil extends LuceneTestCase {

  // Ensure ArrayUtil.getNextSize gives linear amortized cost of realloc/copy
  public void testGrowth() {
    int currentSize = 0;
    long copyCost = 0;

    // Make sure ArrayUtil hits Integer.MAX_VALUE, if we insist:
    while(currentSize != Integer.MAX_VALUE) {
      int nextSize = ArrayUtil.oversize(1+currentSize, RamUsageEstimator.NUM_BYTES_OBJECT_REF);
      assertTrue(nextSize > currentSize);
      if (currentSize > 0) {
        copyCost += currentSize;
        double copyCostPerElement = ((double) copyCost)/currentSize;
        assertTrue("cost " + copyCostPerElement, copyCostPerElement < 10.0);
      }
      currentSize = nextSize;
    }
  }

  public void testMaxSize() {
    // intentionally pass invalid elemSizes:
    for(int elemSize=0;elemSize<10;elemSize++) {
      assertEquals(Integer.MAX_VALUE, ArrayUtil.oversize(Integer.MAX_VALUE, elemSize));
      assertEquals(Integer.MAX_VALUE, ArrayUtil.oversize(Integer.MAX_VALUE-1, elemSize));
    }
  }

  public void testInvalidElementSizes() {
    int num = atLeast(10000);
    for (int iter = 0; iter < num; iter++) {
      final int minTargetSize = random.nextInt(Integer.MAX_VALUE);
      final int elemSize = random.nextInt(11);
      final int v = ArrayUtil.oversize(minTargetSize, elemSize);
      assertTrue(v >= minTargetSize);
    }
  }

  public void testParseInt() throws Exception {
    int test;
    try {
      test = ArrayUtil.parseInt("".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt("foo".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt(String.valueOf(Long.MAX_VALUE).toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt("0.34".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }

    try {
      test = ArrayUtil.parseInt("1".toCharArray());
      assertTrue(test + " does not equal: " + 1, test == 1);
      test = ArrayUtil.parseInt("-10000".toCharArray());
      assertTrue(test + " does not equal: " + -10000, test == -10000);
      test = ArrayUtil.parseInt("1923".toCharArray());
      assertTrue(test + " does not equal: " + 1923, test == 1923);
      test = ArrayUtil.parseInt("-1".toCharArray());
      assertTrue(test + " does not equal: " + -1, test == -1);
      test = ArrayUtil.parseInt("foo 1923 bar".toCharArray(), 4, 4);
      assertTrue(test + " does not equal: " + 1923, test == 1923);
    } catch (NumberFormatException e) {
      e.printStackTrace();
      assertTrue(false);
    }

  }

  
  private Integer[] createRandomArray(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 a;
  }
  
  public void testQuickSort() {
    int num = atLeast(50);
    for (int i = 0; i < num; i++) {
      Integer[] a1 = createRandomArray(1000), a2 = a1.clone();
      ArrayUtil.quickSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
      
      a1 = createRandomArray(1000);
      a2 = a1.clone();
      ArrayUtil.quickSort(a1, Collections.reverseOrder());
      Arrays.sort(a2, Collections.reverseOrder());
      assertArrayEquals(a2, a1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      ArrayUtil.quickSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
    }
  }
  
  private Integer[] createSparseRandomArray(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(2));
    }
    return a;
  }
  
  // This is a test for LUCENE-3054 (which fails without the merge sort fall back with stack overflow in most cases)
  public void testQuickToMergeSortFallback() {
    int num = atLeast(50);
    for (int i = 0; i < num; i++) {
      Integer[] a1 = createSparseRandomArray(40000), a2 = a1.clone();
      ArrayUtil.quickSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
    }
  }
  
  public void testMergeSort() {
    int num = atLeast(50);
    for (int i = 0; i < num; i++) {
      Integer[] a1 = createRandomArray(1000), a2 = a1.clone();
      ArrayUtil.mergeSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
      
      a1 = createRandomArray(1000);
      a2 = a1.clone();
      ArrayUtil.mergeSort(a1, Collections.reverseOrder());
      Arrays.sort(a2, Collections.reverseOrder());
      assertArrayEquals(a2, a1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      ArrayUtil.mergeSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
    }
  }
  
  public void testInsertionSort() {
    for (int i = 0, c = atLeast(500); i < c; i++) {
      Integer[] a1 = createRandomArray(30), a2 = a1.clone();
      ArrayUtil.insertionSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
      
      a1 = createRandomArray(30);
      a2 = a1.clone();
      ArrayUtil.insertionSort(a1, Collections.reverseOrder());
      Arrays.sort(a2, Collections.reverseOrder());
      assertArrayEquals(a2, a1);
      // reverse back, so we can test that completely backwards sorted array (worst case) is working:
      ArrayUtil.insertionSort(a1);
      Arrays.sort(a2);
      assertArrayEquals(a2, a1);
    }
  }
  
  static class Item implements Comparable<Item> {
    final int val, order;
    
    Item(int val, int order) {
      this.val = val;
      this.order = order;
    }
    
    public int compareTo(Item other) {
      return this.order - other.order;
    }
    
    @Override
    public String toString() {
      return Integer.toString(val);
    }
  }
  
  public void testMergeSortStability() {
    Item[] items = new Item[100];
    for (int i = 0; i < items.length; i++) {
      // half of the items have value but same order. The value of this items is sorted,
      // so they should always be in order after sorting.
      // The other half has defined order, but no (-1) value (they should appear after
      // all above, when sorted).
      final boolean equal = random.nextBoolean();
      items[i] = new Item(equal ? (i+1) : -1, equal ? 0 : (random.nextInt(1000)+1));
    }
    
    if (VERBOSE) System.out.println("Before: " + Arrays.toString(items));
    // if you replace this with ArrayUtil.quickSort(), test should fail:
    ArrayUtil.mergeSort(items);
    if (VERBOSE) System.out.println("Sorted: " + Arrays.toString(items));
    
    Item last = items[0];
    for (int i = 1; i < items.length; i++) {
      final Item act = items[i];
      if (act.order == 0) {
        // order of "equal" items should be not mixed up
        assertTrue(act.val > last.val);
      }
      assertTrue(act.order >= last.order);
      last = act;
    }
  }
  
  // should produce no exceptions
  public void testEmptyArraySort() {
    Integer[] a = new Integer[0];
    ArrayUtil.quickSort(a);
    ArrayUtil.mergeSort(a);
    ArrayUtil.insertionSort(a);
    ArrayUtil.quickSort(a, Collections.reverseOrder());
    ArrayUtil.mergeSort(a, Collections.reverseOrder());
    ArrayUtil.insertionSort(a, Collections.reverseOrder());
  }
  
}