it.unimi.dsi.fastutil.objects.Object2ReferenceSortedMaps Maven / Gradle / Ivy
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/*
* Copyright (C) 2002-2022 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.objects;
import it.unimi.dsi.fastutil.objects.Object2ReferenceSortedMap.FastSortedEntrySet;
import java.util.Comparator;
import java.util.Map;
import java.util.SortedMap;
import java.util.NoSuchElementException;
/**
* A class providing static methods and objects that do useful things with type-specific sorted
* maps.
*
* @see java.util.Collections
*/
public final class Object2ReferenceSortedMaps {
private Object2ReferenceSortedMaps() {
}
/**
* Returns a comparator for entries based on a given comparator on keys.
*
* @param comparator a comparator on keys.
* @return the associated comparator on entries.
*/
public static Comparator> entryComparator(final Comparator comparator) {
return (Comparator>)(x, y) -> comparator.compare((x.getKey()), (y.getKey()));
}
/**
* Returns a bidirectional iterator that will be {@linkplain FastSortedEntrySet fast}, if possible,
* on the {@linkplain Map#entrySet() entry set} of the provided {@code map}.
*
* @param map a map from which we will try to extract a (fast) bidirectional iterator on the entry
* set.
* @return a bidirectional iterator on the entry set of the given map that will be fast, if
* possible.
* @since 8.0.0
*/
@SuppressWarnings("unchecked")
public static ObjectBidirectionalIterator> fastIterator(Object2ReferenceSortedMap map) {
final ObjectSortedSet> entries = map.object2ReferenceEntrySet();
return entries instanceof Object2ReferenceSortedMap.FastSortedEntrySet ? ((Object2ReferenceSortedMap.FastSortedEntrySet)entries).fastIterator() : entries.iterator();
}
/**
* Returns an iterable yielding a bidirectional iterator that will be {@linkplain FastSortedEntrySet
* fast}, if possible, on the {@linkplain Map#entrySet() entry set} of the provided {@code map}.
*
* @param map a map from which we will try to extract an iterable yielding a (fast) bidirectional
* iterator on the entry set.
* @return an iterable yielding a bidirectional iterator on the entry set of the given map that will
* be fast, if possible.
* @since 8.0.0
*/
@SuppressWarnings("unchecked")
public static ObjectBidirectionalIterable> fastIterable(Object2ReferenceSortedMap map) {
final ObjectSortedSet> entries = map.object2ReferenceEntrySet();
return entries instanceof Object2ReferenceSortedMap.FastSortedEntrySet ? ((Object2ReferenceSortedMap.FastSortedEntrySet)entries)::fastIterator : entries;
}
/**
* An immutable class representing an empty type-specific sorted map.
*
*
* This class may be useful to implement your own in case you subclass a type-specific sorted map.
*/
public static class EmptySortedMap extends Object2ReferenceMaps.EmptyMap implements Object2ReferenceSortedMap, java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected EmptySortedMap() {
}
@Override
public Comparator comparator() {
return null;
}
@Override
public ObjectSortedSet> object2ReferenceEntrySet() {
return ObjectSortedSets.EMPTY_SET;
}
/** {@inheritDoc} */
@Override
public ObjectSortedSet> entrySet() {
return ObjectSortedSets.EMPTY_SET;
}
@SuppressWarnings("unchecked")
@Override
public ObjectSortedSet keySet() {
return ObjectSortedSets.EMPTY_SET;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap subMap(final K from, final K to) {
return EMPTY_MAP;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap headMap(final K to) {
return EMPTY_MAP;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap tailMap(final K from) {
return EMPTY_MAP;
}
@Override
public K firstKey() {
throw new NoSuchElementException();
}
@Override
public K lastKey() {
throw new NoSuchElementException();
}
}
/**
* An empty sorted map (immutable). It is serializable and cloneable.
*/
@SuppressWarnings("rawtypes")
public static final EmptySortedMap EMPTY_MAP = new EmptySortedMap();
/**
* Returns an empty sorted map (immutable). It is serializable and cloneable.
*
*
* This method provides a typesafe access to {@link #EMPTY_MAP}.
*
* @return an empty sorted map (immutable).
*/
@SuppressWarnings("unchecked")
public static Object2ReferenceSortedMap emptyMap() {
return EMPTY_MAP;
}
/**
* An immutable class representing a type-specific singleton sorted map.
*
*
* This class may be useful to implement your own in case you subclass a type-specific sorted map.
*/
public static class Singleton extends Object2ReferenceMaps.Singleton implements Object2ReferenceSortedMap, java.io.Serializable, Cloneable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Comparator comparator;
protected Singleton(final K key, final V value, Comparator comparator) {
super(key, value);
this.comparator = comparator;
}
protected Singleton(final K key, final V value) {
this(key, value, null);
}
@SuppressWarnings("unchecked")
final int compare(final K k1, final K k2) {
return comparator == null ? (((Comparable)(k1)).compareTo(k2)) : comparator.compare(k1, k2);
}
@Override
public Comparator comparator() {
return comparator;
}
@SuppressWarnings("unchecked")
@Override
public ObjectSortedSet> object2ReferenceEntrySet() {
if (entries == null) entries = ObjectSortedSets.singleton(new AbstractObject2ReferenceMap.BasicEntry<>(key, value), entryComparator(comparator));
return (ObjectSortedSet>)entries;
}
/** {@inheritDoc} */
@Override
@SuppressWarnings({ "rawtypes", "unchecked" })
public ObjectSortedSet> entrySet() {
return (ObjectSortedSet)object2ReferenceEntrySet();
}
@Override
public ObjectSortedSet keySet() {
if (keys == null) keys = ObjectSortedSets.singleton(key, comparator);
return (ObjectSortedSet)keys;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap subMap(final K from, final K to) {
if (compare(from, key) <= 0 && compare(key, to) < 0) return this;
return EMPTY_MAP;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap headMap(final K to) {
if (compare(key, to) < 0) return this;
return EMPTY_MAP;
}
@SuppressWarnings("unchecked")
@Override
public Object2ReferenceSortedMap tailMap(final K from) {
if (compare(from, key) <= 0) return this;
return EMPTY_MAP;
}
@Override
public K firstKey() {
return key;
}
@Override
public K lastKey() {
return key;
}
}
/**
* Returns a type-specific immutable sorted map containing only the specified pair. The returned
* sorted map is serializable and cloneable.
*
*
* Note that albeit the returned map is immutable, its default return value may be changed.
*
* @param key the only key of the returned sorted map.
* @param value the only value of the returned sorted map.
* @return a type-specific immutable sorted map containing just the pair {@code <key,value>}.
*/
public static Object2ReferenceSortedMap singleton(final K key, V value) {
return new Singleton<>((key), (value));
}
/**
* Returns a type-specific immutable sorted map containing only the specified pair. The returned
* sorted map is serializable and cloneable.
*
*
* Note that albeit the returned map is immutable, its default return value may be changed.
*
* @param key the only key of the returned sorted map.
* @param value the only value of the returned sorted map.
* @param comparator the comparator to use in the returned sorted map.
* @return a type-specific immutable sorted map containing just the pair {@code <key,value>}.
*/
public static Object2ReferenceSortedMap singleton(final K key, V value, Comparator comparator) {
return new Singleton<>((key), (value), comparator);
}
/** A synchronized wrapper class for sorted maps. */
public static class SynchronizedSortedMap extends Object2ReferenceMaps.SynchronizedMap implements Object2ReferenceSortedMap, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2ReferenceSortedMap sortedMap;
protected SynchronizedSortedMap(final Object2ReferenceSortedMap m, final Object sync) {
super(m, sync);
sortedMap = m;
}
protected SynchronizedSortedMap(final Object2ReferenceSortedMap m) {
super(m);
sortedMap = m;
}
@Override
public Comparator comparator() {
synchronized (sync) {
return sortedMap.comparator();
}
}
@Override
public ObjectSortedSet> object2ReferenceEntrySet() {
if (entries == null) entries = ObjectSortedSets.synchronize(sortedMap.object2ReferenceEntrySet(), sync);
return (ObjectSortedSet>)entries;
}
/** {@inheritDoc} */
@Override
@SuppressWarnings({ "rawtypes", "unchecked" })
public ObjectSortedSet> entrySet() {
return (ObjectSortedSet)object2ReferenceEntrySet();
}
@Override
public ObjectSortedSet keySet() {
if (keys == null) keys = ObjectSortedSets.synchronize(sortedMap.keySet(), sync);
return (ObjectSortedSet)keys;
}
@Override
public Object2ReferenceSortedMap subMap(final K from, final K to) {
return new SynchronizedSortedMap<>(sortedMap.subMap(from, to), sync);
}
@Override
public Object2ReferenceSortedMap headMap(final K to) {
return new SynchronizedSortedMap<>(sortedMap.headMap(to), sync);
}
@Override
public Object2ReferenceSortedMap tailMap(final K from) {
return new SynchronizedSortedMap<>(sortedMap.tailMap(from), sync);
}
@Override
public K firstKey() {
synchronized (sync) {
return sortedMap.firstKey();
}
}
@Override
public K lastKey() {
synchronized (sync) {
return sortedMap.lastKey();
}
}
}
/**
* Returns a synchronized type-specific sorted map backed by the given type-specific sorted map.
*
* @param m the sorted map to be wrapped in a synchronized sorted map.
* @return a synchronized view of the specified sorted map.
* @see java.util.Collections#synchronizedSortedMap(SortedMap)
*/
public static Object2ReferenceSortedMap synchronize(final Object2ReferenceSortedMap m) {
return new SynchronizedSortedMap<>(m);
}
/**
* Returns a synchronized type-specific sorted map backed by the given type-specific sorted map,
* using an assigned object to synchronize.
*
* @param m the sorted map to be wrapped in a synchronized sorted map.
* @param sync an object that will be used to synchronize the access to the sorted sorted map.
* @return a synchronized view of the specified sorted map.
* @see java.util.Collections#synchronizedSortedMap(SortedMap)
*/
public static Object2ReferenceSortedMap synchronize(final Object2ReferenceSortedMap m, final Object sync) {
return new SynchronizedSortedMap<>(m, sync);
}
/** An unmodifiable wrapper class for sorted maps. */
public static class UnmodifiableSortedMap extends Object2ReferenceMaps.UnmodifiableMap implements Object2ReferenceSortedMap, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353129L;
protected final Object2ReferenceSortedMap sortedMap;
protected UnmodifiableSortedMap(final Object2ReferenceSortedMap m) {
super(m);
sortedMap = m;
}
@Override
public Comparator comparator() {
return sortedMap.comparator();
}
@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public ObjectSortedSet> object2ReferenceEntrySet() {
if (entries == null) entries = ObjectSortedSets.unmodifiable((ObjectSortedSet)sortedMap.object2ReferenceEntrySet());
return (ObjectSortedSet>)entries;
}
/** {@inheritDoc} */
@Override
@SuppressWarnings({ "rawtypes", "unchecked" })
public ObjectSortedSet> entrySet() {
return (ObjectSortedSet)object2ReferenceEntrySet();
}
@Override
public ObjectSortedSet keySet() {
if (keys == null) keys = ObjectSortedSets.unmodifiable(sortedMap.keySet());
return (ObjectSortedSet)keys;
}
@Override
public Object2ReferenceSortedMap subMap(final K from, final K to) {
return new UnmodifiableSortedMap<>(sortedMap.subMap(from, to));
}
@Override
public Object2ReferenceSortedMap headMap(final K to) {
return new UnmodifiableSortedMap<>(sortedMap.headMap(to));
}
@Override
public Object2ReferenceSortedMap tailMap(final K from) {
return new UnmodifiableSortedMap<>(sortedMap.tailMap(from));
}
@Override
public K firstKey() {
return sortedMap.firstKey();
}
@Override
public K lastKey() {
return sortedMap.lastKey();
}
}
/**
* Returns an unmodifiable type-specific sorted map backed by the given type-specific sorted map.
*
* @param m the sorted map to be wrapped in an unmodifiable sorted map.
* @return an unmodifiable view of the specified sorted map.
* @see java.util.Collections#unmodifiableSortedMap(SortedMap)
*/
public static Object2ReferenceSortedMap unmodifiable(final Object2ReferenceSortedMap m) {
return new UnmodifiableSortedMap<>(m);
}
}