Java example source code file (SampleElements.java)

This example Java source code file (SampleElements.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

chars, collider, colliders, enums, ints, iterable, iterator, override, sampleelements, string, strings, unhashableobject, unhashables, util

The SampleElements.java Java example source code

/*
 * Copyright (C) 2008 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.testing;

import com.google.common.annotations.GwtCompatible;

import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * A container class for the five sample elements we need for testing.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public class SampleElements<E> implements Iterable {
  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;
  private final E e1;
  private final E e2;
  private final E e3;
  private final E e4;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override
  public Iterator<E> iterator() {
    return asList().iterator();
  }

  public List<E> asList() {
    return Arrays.asList(e0(), e1(), e2(), e3(), e4());
  }

  public static class Strings extends SampleElements<String> {
    public Strings() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super("b", "a", "c", "d", "e");
    }

    // for testing SortedSet and SortedMap methods
    public static final String BEFORE_FIRST = "\0";
    public static final String BEFORE_FIRST_2 = "\0\0";
    public static final String MIN_ELEMENT = "a";
    public static final String AFTER_LAST = "z";
    public static final String AFTER_LAST_2 = "zz";
  }

  public static class Chars extends SampleElements<Character> {
    public Chars() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super('b', 'a', 'c', 'd', 'e');
    }
  }

  public static class Enums extends SampleElements<AnEnum> {
    public Enums() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super(AnEnum.B, AnEnum.A, AnEnum.C, AnEnum.D, AnEnum.E);
    }
  }

  public static class Ints extends SampleElements<Integer> {
    public Ints() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super(1, 0, 2, 3, 4);
    }
  }

  public static <K, V> SampleElements> mapEntries(
      SampleElements<K> keys, SampleElements values) {
    return new SampleElements<Map.Entry(
        Helpers.mapEntry(keys.e0(), values.e0()),
        Helpers.mapEntry(keys.e1(), values.e1()),
        Helpers.mapEntry(keys.e2(), values.e2()),
        Helpers.mapEntry(keys.e3(), values.e3()),
        Helpers.mapEntry(keys.e4(), values.e4()));
  }

  public E e0() {
    return e0;
  }

  public E e1() {
    return e1;
  }

  public E e2() {
    return e2;
  }

  public E e3() {
    return e3;
  }

  public E e4() {
    return e4;
  }

  public static class Unhashables extends SampleElements<UnhashableObject> {
    public Unhashables() {
      super(
          new UnhashableObject(1),
          new UnhashableObject(2),
          new UnhashableObject(3),
          new UnhashableObject(4),
          new UnhashableObject(5));
    }
  }

  public static class Colliders extends SampleElements<Object> {
    public Colliders() {
      super(new Collider(1), new Collider(2), new Collider(3), new Collider(4), new Collider(5));
    }
  }

  private static class Collider {
    final int value;

    Collider(int value) {
      this.value = value;
    }

    @Override
    public boolean equals(Object obj) {
      return obj instanceof Collider && ((Collider) obj).value == value;
    }

    @Override
    public int hashCode() {
      return 1; // evil!
    }
  }
}