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Java example source code file (TreeMultimapExplicitTest.java)

This example Java source code file (TreeMultimapExplicitTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

collection, comparator, decreasing_int_comparator, gwtcompatible, gwtincompatible, integer, override, serializabletester, setmultimap, sortedset, stringlength, testcase, treemultimap, treemultimapexplicittest, util

The TreeMultimapExplicitTest.java Java example source code

/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed 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.
 */

package com.google.common.collect;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.testing.SerializableTester;

import junit.framework.TestCase;

import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedSet;

/**
 * Unit tests for {@code TreeMultimap} with explicit comparators.
 *
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
public class TreeMultimapExplicitTest extends TestCase {

  /**
   * Compare strings lengths, and if the lengths are equal compare the strings.
   * A {@code null} is less than any non-null value.
   */
  private enum StringLength implements Comparator<String> {
    COMPARATOR;

    @Override
    public int compare(String first, String second) {
      if (first == second) {
        return 0;
      } else if (first == null) {
        return -1;
      } else if (second == null) {
        return 1;
      } else if (first.length() != second.length()) {
        return first.length() - second.length();
      } else {
        return first.compareTo(second);
      }
    }
  }

  /**
   * Decreasing integer values. A {@code null} comes before any non-null value.
   */
  private static final Comparator<Integer> DECREASING_INT_COMPARATOR =
      Ordering.<Integer>natural().reverse().nullsFirst();

  private SetMultimap<String, Integer> create() {
    return TreeMultimap.create(
        StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
  }

  /**
   * Create and populate a {@code TreeMultimap} with explicit comparators.
   */
  private TreeMultimap<String, Integer> createPopulate() {
    TreeMultimap<String, Integer> multimap = TreeMultimap.create(
        StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    multimap.put("google", 2);
    multimap.put("google", 6);
    multimap.put(null, 3);
    multimap.put(null, 1);
    multimap.put(null, 7);
    multimap.put("tree", 0);
    multimap.put("tree", null);
    return multimap;
  }

  /**
   * Test that a TreeMultimap created from another uses the natural ordering.
   */
  public void testMultimapCreateFromTreeMultimap() {
    TreeMultimap<String, Integer> tree = TreeMultimap.create(
        StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    tree.put("google", 2);
    tree.put("google", 6);
    tree.put("tree", 0);
    tree.put("tree", 3);
    assertThat(tree.keySet()).containsExactly("tree", "google").inOrder();
    assertThat(tree.get("google")).containsExactly(6, 2).inOrder();

    TreeMultimap<String, Integer> copy = TreeMultimap.create(tree);
    assertEquals(tree, copy);
    assertThat(copy.keySet()).containsExactly("google", "tree").inOrder();
    assertThat(copy.get("google")).containsExactly(2, 6).inOrder();
    assertEquals(Ordering.natural(), copy.keyComparator());
    assertEquals(Ordering.natural(), copy.valueComparator());
    assertEquals(Ordering.natural(), copy.get("google").comparator());
  }

  public void testToString() {
    Multimap<String, Integer> multimap = create();
    multimap.put("foo", 3);
    multimap.put("bar", 1);
    multimap.putAll("foo", Arrays.asList(-1, 2, 4));
    multimap.putAll("bar", Arrays.asList(2, 3));
    multimap.put("foo", 1);
    assertEquals("{bar=[3, 2, 1], foo=[4, 3, 2, 1, -1]}",
        multimap.toString());
  }

  public void testGetComparator() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertEquals(StringLength.COMPARATOR, multimap.keyComparator());
    assertEquals(DECREASING_INT_COMPARATOR, multimap.valueComparator());
  }

  public void testOrderedGet() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertThat(multimap.get(null)).containsExactly(7, 3, 1).inOrder();
    assertThat(multimap.get("google")).containsExactly(6, 2).inOrder();
    assertThat(multimap.get("tree")).containsExactly(null, 0).inOrder();
  }

  public void testOrderedKeySet() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertThat(multimap.keySet()).containsExactly(null, "tree", "google").inOrder();
  }

  public void testOrderedAsMapEntries() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    Iterator<Map.Entry> iterator =
        multimap.asMap().entrySet().iterator();
    Map.Entry<String, Collection entry = iterator.next();
    assertEquals(null, entry.getKey());
    assertThat(entry.getValue()).containsExactly(7, 3, 1);
    entry = iterator.next();
    assertEquals("tree", entry.getKey());
    assertThat(entry.getValue()).containsExactly(null, 0);
    entry = iterator.next();
    assertEquals("google", entry.getKey());
    assertThat(entry.getValue()).containsExactly(6, 2);
  }

  public void testOrderedEntries() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertThat(multimap.entries()).containsExactly(
        Maps.immutableEntry((String) null, 7),
        Maps.immutableEntry((String) null, 3),
        Maps.immutableEntry((String) null, 1),
        Maps.immutableEntry("tree", (Integer) null),
        Maps.immutableEntry("tree", 0),
        Maps.immutableEntry("google", 6),
        Maps.immutableEntry("google", 2)).inOrder();
  }

  public void testOrderedValues() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertThat(multimap.values()).containsExactly(7, 3, 1, null, 0, 6, 2).inOrder();
  }

  public void testComparator() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    assertEquals(DECREASING_INT_COMPARATOR, multimap.get("foo").comparator());
    assertEquals(DECREASING_INT_COMPARATOR,
        multimap.get("missing").comparator());
  }

  public void testMultimapComparators() {
    Multimap<String, Integer> multimap = create();
    multimap.put("foo", 3);
    multimap.put("bar", 1);
    multimap.putAll("foo", Arrays.asList(-1, 2, 4));
    multimap.putAll("bar", Arrays.asList(2, 3));
    multimap.put("foo", 1);
    TreeMultimap<String, Integer> copy =
        TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
    copy.putAll(multimap);
    assertEquals(multimap, copy);
    assertEquals(StringLength.COMPARATOR, copy.keyComparator());
    assertEquals(DECREASING_INT_COMPARATOR, copy.valueComparator());
  }

  public void testSortedKeySet() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    SortedSet<String> keySet = multimap.keySet();

    assertEquals(null, keySet.first());
    assertEquals("google", keySet.last());
    assertEquals(StringLength.COMPARATOR, keySet.comparator());
    assertEquals(Sets.newHashSet(null, "tree"), keySet.headSet("yahoo"));
    assertEquals(Sets.newHashSet("google"), keySet.tailSet("yahoo"));
    assertEquals(Sets.newHashSet("tree"), keySet.subSet("ask", "yahoo"));
  }

  @GwtIncompatible // SerializableTester
  public void testExplicitComparatorSerialization() {
    TreeMultimap<String, Integer> multimap = createPopulate();
    TreeMultimap<String, Integer> copy
        = SerializableTester.reserializeAndAssert(multimap);
    assertThat(copy.values()).containsExactly(7, 3, 1, null, 0, 6, 2).inOrder();
    assertThat(copy.keySet()).containsExactly(null, "tree", "google").inOrder();
    assertEquals(multimap.keyComparator(), copy.keyComparator());
    assertEquals(multimap.valueComparator(), copy.valueComparator());
  }
}

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