Java example source code file (AbstractNavigableMap.java)

This example Java source code file (AbstractNavigableMap.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

annotation, descendingmap, entry, gwtincompatible, iterator, iteratorbasedabstractmap, navigablemap, navigableset, nosuchelementexception, nullable, object, override, sortedmap, util

The AbstractNavigableMap.java Java example source code

/*
 * Copyright (C) 2012 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 com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Maps.IteratorBasedAbstractMap;

import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedMap;

import javax.annotation.Nullable;

/**
 * Skeletal implementation of {@link NavigableMap}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
abstract class AbstractNavigableMap<K, V> extends IteratorBasedAbstractMap
    implements NavigableMap<K, V> {

  @Override
  @Nullable
  public abstract V get(@Nullable Object key);

  @Override
  @Nullable
  public Entry<K, V> firstEntry() {
    return Iterators.getNext(entryIterator(), null);
  }

  @Override
  @Nullable
  public Entry<K, V> lastEntry() {
    return Iterators.getNext(descendingEntryIterator(), null);
  }

  @Override
  @Nullable
  public Entry<K, V> pollFirstEntry() {
    return Iterators.pollNext(entryIterator());
  }

  @Override
  @Nullable
  public Entry<K, V> pollLastEntry() {
    return Iterators.pollNext(descendingEntryIterator());
  }

  @Override
  public K firstKey() {
    Entry<K, V> entry = firstEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

  @Override
  public K lastKey() {
    Entry<K, V> entry = lastEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

  @Override
  @Nullable
  public Entry<K, V> lowerEntry(K key) {
    return headMap(key, false).lastEntry();
  }

  @Override
  @Nullable
  public Entry<K, V> floorEntry(K key) {
    return headMap(key, true).lastEntry();
  }

  @Override
  @Nullable
  public Entry<K, V> ceilingEntry(K key) {
    return tailMap(key, true).firstEntry();
  }

  @Override
  @Nullable
  public Entry<K, V> higherEntry(K key) {
    return tailMap(key, false).firstEntry();
  }

  @Override
  public K lowerKey(K key) {
    return Maps.keyOrNull(lowerEntry(key));
  }

  @Override
  public K floorKey(K key) {
    return Maps.keyOrNull(floorEntry(key));
  }

  @Override
  public K ceilingKey(K key) {
    return Maps.keyOrNull(ceilingEntry(key));
  }

  @Override
  public K higherKey(K key) {
    return Maps.keyOrNull(higherEntry(key));
  }

  abstract Iterator<Entry descendingEntryIterator();

  @Override
  public SortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> headMap(K toKey) {
    return headMap(toKey, false);
  }

  @Override
  public SortedMap<K, V> tailMap(K fromKey) {
    return tailMap(fromKey, true);
  }

  @Override
  public NavigableSet<K> navigableKeySet() {
    return new Maps.NavigableKeySet<K, V>(this);
  }

  @Override
  public Set<K> keySet() {
    return navigableKeySet();
  }

  @Override
  public NavigableSet<K> descendingKeySet() {
    return descendingMap().navigableKeySet();
  }

  @Override
  public NavigableMap<K, V> descendingMap() {
    return new DescendingMap();
  }

  private final class DescendingMap extends Maps.DescendingMap<K, V> {
    @Override
    NavigableMap<K, V> forward() {
      return AbstractNavigableMap.this;
    }

    @Override
    Iterator<Entry entryIterator() {
      return descendingEntryIterator();
    }
  }
}