eaglercraft-1.8/sources/main/java/com/google/common/collect/ForwardingNavigableMap.java
2022-12-25 01:12:28 -08:00

421 lines
12 KiB
Java

/*
* 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 static com.google.common.collect.CollectPreconditions.checkRemove;
import static com.google.common.collect.Maps.keyOrNull;
import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.SortedMap;
import com.google.common.annotations.Beta;
/**
* A navigable map which forwards all its method calls to another navigable map.
* Subclasses should override one or more methods to modify the behavior of the
* backing map as desired per the
* <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator
* pattern</a>.
*
* <p>
* <i>Warning:</i> The methods of {@code ForwardingNavigableMap} forward
* <i>indiscriminately</i> to the methods of the delegate. For example,
* overriding {@link #put} alone <i>will not</i> change the behavior of
* {@link #putAll}, which can lead to unexpected behavior. In this case, you
* should override {@code putAll} as well, either providing your own
* implementation, or delegating to the provided {@code standardPutAll} method.
*
* <p>
* Each of the {@code standard} methods uses the map's comparator (or the
* natural ordering of the elements, if there is no comparator) to test element
* equality. As a result, if the comparator is not consistent with equals, some
* of the standard implementations may violate the {@code Map} contract.
*
* <p>
* The {@code standard} methods and the collection views they return are not
* guaranteed to be thread-safe, even when all of the methods that they depend
* on are thread-safe.
*
* @author Louis Wasserman
* @since 12.0
*/
public abstract class ForwardingNavigableMap<K, V> extends ForwardingSortedMap<K, V> implements NavigableMap<K, V> {
/** Constructor for use by subclasses. */
protected ForwardingNavigableMap() {
}
@Override
protected abstract NavigableMap<K, V> delegate();
@Override
public Entry<K, V> lowerEntry(K key) {
return delegate().lowerEntry(key);
}
/**
* A sensible definition of {@link #lowerEntry} in terms of the
* {@code lastEntry()} of {@link #headMap(Object, boolean)}. If you override
* {@code headMap}, you may wish to override {@code lowerEntry} to forward to
* this implementation.
*/
protected Entry<K, V> standardLowerEntry(K key) {
return headMap(key, false).lastEntry();
}
@Override
public K lowerKey(K key) {
return delegate().lowerKey(key);
}
/**
* A sensible definition of {@link #lowerKey} in terms of {@code lowerEntry}. If
* you override {@link #lowerEntry}, you may wish to override {@code lowerKey}
* to forward to this implementation.
*/
protected K standardLowerKey(K key) {
return keyOrNull(lowerEntry(key));
}
@Override
public Entry<K, V> floorEntry(K key) {
return delegate().floorEntry(key);
}
/**
* A sensible definition of {@link #floorEntry} in terms of the
* {@code lastEntry()} of {@link #headMap(Object, boolean)}. If you override
* {@code headMap}, you may wish to override {@code floorEntry} to forward to
* this implementation.
*/
protected Entry<K, V> standardFloorEntry(K key) {
return headMap(key, true).lastEntry();
}
@Override
public K floorKey(K key) {
return delegate().floorKey(key);
}
/**
* A sensible definition of {@link #floorKey} in terms of {@code floorEntry}. If
* you override {@code floorEntry}, you may wish to override {@code floorKey} to
* forward to this implementation.
*/
protected K standardFloorKey(K key) {
return keyOrNull(floorEntry(key));
}
@Override
public Entry<K, V> ceilingEntry(K key) {
return delegate().ceilingEntry(key);
}
/**
* A sensible definition of {@link #ceilingEntry} in terms of the
* {@code firstEntry()} of {@link #tailMap(Object, boolean)}. If you override
* {@code tailMap}, you may wish to override {@code ceilingEntry} to forward to
* this implementation.
*/
protected Entry<K, V> standardCeilingEntry(K key) {
return tailMap(key, true).firstEntry();
}
@Override
public K ceilingKey(K key) {
return delegate().ceilingKey(key);
}
/**
* A sensible definition of {@link #ceilingKey} in terms of
* {@code ceilingEntry}. If you override {@code ceilingEntry}, you may wish to
* override {@code ceilingKey} to forward to this implementation.
*/
protected K standardCeilingKey(K key) {
return keyOrNull(ceilingEntry(key));
}
@Override
public Entry<K, V> higherEntry(K key) {
return delegate().higherEntry(key);
}
/**
* A sensible definition of {@link #higherEntry} in terms of the
* {@code firstEntry()} of {@link #tailMap(Object, boolean)}. If you override
* {@code tailMap}, you may wish to override {@code higherEntry} to forward to
* this implementation.
*/
protected Entry<K, V> standardHigherEntry(K key) {
return tailMap(key, false).firstEntry();
}
@Override
public K higherKey(K key) {
return delegate().higherKey(key);
}
/**
* A sensible definition of {@link #higherKey} in terms of {@code higherEntry}.
* If you override {@code higherEntry}, you may wish to override
* {@code higherKey} to forward to this implementation.
*/
protected K standardHigherKey(K key) {
return keyOrNull(higherEntry(key));
}
@Override
public Entry<K, V> firstEntry() {
return delegate().firstEntry();
}
/**
* A sensible definition of {@link #firstEntry} in terms of the
* {@code iterator()} of {@link #entrySet}. If you override {@code entrySet},
* you may wish to override {@code firstEntry} to forward to this
* implementation.
*/
protected Entry<K, V> standardFirstEntry() {
return Iterables.getFirst(entrySet(), null);
}
/**
* A sensible definition of {@link #firstKey} in terms of {@code firstEntry}. If
* you override {@code firstEntry}, you may wish to override {@code firstKey} to
* forward to this implementation.
*/
protected K standardFirstKey() {
Entry<K, V> entry = firstEntry();
if (entry == null) {
throw new NoSuchElementException();
} else {
return entry.getKey();
}
}
@Override
public Entry<K, V> lastEntry() {
return delegate().lastEntry();
}
/**
* A sensible definition of {@link #lastEntry} in terms of the
* {@code iterator()} of the {@link #entrySet} of {@link #descendingMap}. If you
* override {@code descendingMap}, you may wish to override {@code lastEntry} to
* forward to this implementation.
*/
protected Entry<K, V> standardLastEntry() {
return Iterables.getFirst(descendingMap().entrySet(), null);
}
/**
* A sensible definition of {@link #lastKey} in terms of {@code lastEntry}. If
* you override {@code lastEntry}, you may wish to override {@code lastKey} to
* forward to this implementation.
*/
protected K standardLastKey() {
Entry<K, V> entry = lastEntry();
if (entry == null) {
throw new NoSuchElementException();
} else {
return entry.getKey();
}
}
@Override
public Entry<K, V> pollFirstEntry() {
return delegate().pollFirstEntry();
}
/**
* A sensible definition of {@link #pollFirstEntry} in terms of the
* {@code iterator} of {@code entrySet}. If you override {@code entrySet}, you
* may wish to override {@code pollFirstEntry} to forward to this
* implementation.
*/
protected Entry<K, V> standardPollFirstEntry() {
return Iterators.pollNext(entrySet().iterator());
}
@Override
public Entry<K, V> pollLastEntry() {
return delegate().pollLastEntry();
}
/**
* A sensible definition of {@link #pollFirstEntry} in terms of the
* {@code iterator} of the {@code entrySet} of {@code descendingMap}. If you
* override {@code descendingMap}, you may wish to override
* {@code pollFirstEntry} to forward to this implementation.
*/
protected Entry<K, V> standardPollLastEntry() {
return Iterators.pollNext(descendingMap().entrySet().iterator());
}
@Override
public NavigableMap<K, V> descendingMap() {
return delegate().descendingMap();
}
/**
* A sensible implementation of {@link NavigableMap#descendingMap} in terms of
* the methods of this {@code NavigableMap}. In many cases, you may wish to
* override {@link ForwardingNavigableMap#descendingMap} to forward to this
* implementation or a subclass thereof.
*
* <p>
* In particular, this map iterates over entries with repeated calls to
* {@link NavigableMap#lowerEntry}. If a more efficient means of iteration is
* available, you may wish to override the {@code entryIterator()} method of
* this class.
*
* @since 12.0
*/
@Beta
protected class StandardDescendingMap extends Maps.DescendingMap<K, V> {
/** Constructor for use by subclasses. */
public StandardDescendingMap() {
}
@Override
NavigableMap<K, V> forward() {
return ForwardingNavigableMap.this;
}
@Override
protected Iterator<Entry<K, V>> entryIterator() {
return new Iterator<Entry<K, V>>() {
private Entry<K, V> toRemove = null;
private Entry<K, V> nextOrNull = forward().lastEntry();
@Override
public boolean hasNext() {
return nextOrNull != null;
}
@Override
public java.util.Map.Entry<K, V> next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
try {
return nextOrNull;
} finally {
toRemove = nextOrNull;
nextOrNull = forward().lowerEntry(nextOrNull.getKey());
}
}
@Override
public void remove() {
checkRemove(toRemove != null);
forward().remove(toRemove.getKey());
toRemove = null;
}
};
}
}
@Override
public NavigableSet<K> navigableKeySet() {
return delegate().navigableKeySet();
}
/**
* A sensible implementation of {@link NavigableMap#navigableKeySet} in terms of
* the methods of this {@code NavigableMap}. In many cases, you may wish to
* override {@link ForwardingNavigableMap#navigableKeySet} to forward to this
* implementation or a subclass thereof.
*
* @since 12.0
*/
@Beta
protected class StandardNavigableKeySet extends Maps.NavigableKeySet<K, V> {
/** Constructor for use by subclasses. */
public StandardNavigableKeySet() {
super(ForwardingNavigableMap.this);
}
}
@Override
public NavigableSet<K> descendingKeySet() {
return delegate().descendingKeySet();
}
/**
* A sensible definition of {@link #descendingKeySet} as the
* {@code navigableKeySet} of {@link #descendingMap}. (The
* {@link StandardDescendingMap} implementation implements
* {@code navigableKeySet} on its own, so as not to cause an infinite loop.) If
* you override {@code descendingMap}, you may wish to override
* {@code descendingKeySet} to forward to this implementation.
*/
@Beta
protected NavigableSet<K> standardDescendingKeySet() {
return descendingMap().navigableKeySet();
}
/**
* A sensible definition of {@link #subMap(Object, Object)} in terms of
* {@link #subMap(Object, boolean, Object, boolean)}. If you override
* {@code subMap(K, boolean, K, boolean)}, you may wish to override
* {@code subMap} to forward to this implementation.
*/
@Override
protected SortedMap<K, V> standardSubMap(K fromKey, K toKey) {
return subMap(fromKey, true, toKey, false);
}
@Override
public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
return delegate().subMap(fromKey, fromInclusive, toKey, toInclusive);
}
@Override
public NavigableMap<K, V> headMap(K toKey, boolean inclusive) {
return delegate().headMap(toKey, inclusive);
}
@Override
public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
return delegate().tailMap(fromKey, inclusive);
}
/**
* A sensible definition of {@link #headMap(Object)} in terms of
* {@link #headMap(Object, boolean)}. If you override
* {@code headMap(K, boolean)}, you may wish to override {@code headMap} to
* forward to this implementation.
*/
protected SortedMap<K, V> standardHeadMap(K toKey) {
return headMap(toKey, false);
}
/**
* A sensible definition of {@link #tailMap(Object)} in terms of
* {@link #tailMap(Object, boolean)}. If you override
* {@code tailMap(K, boolean)}, you may wish to override {@code tailMap} to
* forward to this implementation.
*/
protected SortedMap<K, V> standardTailMap(K fromKey) {
return tailMap(fromKey, true);
}
}