/*
* Copyright (C) 2009 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.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
import static com.google.common.collect.Maps.keyOrNull;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.WeakOuter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import javax.annotation.Nullable;
/**
* A {@link NavigableMap} whose contents will never change, with many other important properties
* detailed at {@link ImmutableCollection}.
*
* Warning: as with any sorted collection, you are strongly advised not to use a {@link
* Comparator} or {@link Comparable} type whose comparison behavior is inconsistent with
* equals . That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
* if and only if {@code a.equals(b)}. If this advice is not followed, the resulting map will
* not correctly obey its specification.
*
*
See the Guava User Guide article on
* immutable collections .
*
* @author Jared Levy
* @author Louis Wasserman
* @since 2.0 (implements {@code NavigableMap} since 12.0)
*/
@GwtCompatible(serializable = true, emulated = true)
public final class ImmutableSortedMap extends ImmutableSortedMapFauxverideShim
implements NavigableMap {
/*
* TODO(kevinb): Confirm that ImmutableSortedMap is faster to construct and
* uses less memory than TreeMap; then say so in the class Javadoc.
*/
private static final Comparator NATURAL_ORDER = Ordering.natural();
private static final ImmutableSortedMap NATURAL_EMPTY_MAP =
new ImmutableSortedMap(
ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.of());
static ImmutableSortedMap emptyMap(Comparator comparator) {
if (Ordering.natural().equals(comparator)) {
return of();
} else {
return new ImmutableSortedMap(
ImmutableSortedSet.emptySet(comparator), ImmutableList.of());
}
}
/**
* Returns the empty sorted map.
*/
@SuppressWarnings("unchecked")
// unsafe, comparator() returns a comparator on the specified type
// TODO(kevinb): evaluate whether or not of().comparator() should return null
public static ImmutableSortedMap of() {
return (ImmutableSortedMap) NATURAL_EMPTY_MAP;
}
/**
* Returns an immutable map containing a single entry.
*/
public static , V> ImmutableSortedMap of(K k1, V v1) {
return of(Ordering.natural(), k1, v1);
}
/**
* Returns an immutable map containing a single entry.
*/
private static ImmutableSortedMap of(Comparator comparator, K k1, V v1) {
return new ImmutableSortedMap(
new RegularImmutableSortedSet(ImmutableList.of(k1), checkNotNull(comparator)),
ImmutableList.of(v1));
}
private static , V> ImmutableSortedMap ofEntries(
ImmutableMapEntry... entries) {
return fromEntries(Ordering.natural(), false, entries, entries.length);
}
/**
* Returns an immutable sorted map containing the given entries, sorted by the
* natural ordering of their keys.
*
* @throws IllegalArgumentException if the two keys are equal according to
* their natural ordering
*/
@SuppressWarnings("unchecked")
public static , V> ImmutableSortedMap of(
K k1, V v1, K k2, V v2) {
return ofEntries(entryOf(k1, v1), entryOf(k2, v2));
}
/**
* Returns an immutable sorted map containing the given entries, sorted by the
* natural ordering of their keys.
*
* @throws IllegalArgumentException if any two keys are equal according to
* their natural ordering
*/
@SuppressWarnings("unchecked")
public static , V> ImmutableSortedMap of(
K k1, V v1, K k2, V v2, K k3, V v3) {
return ofEntries(entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3));
}
/**
* Returns an immutable sorted map containing the given entries, sorted by the
* natural ordering of their keys.
*
* @throws IllegalArgumentException if any two keys are equal according to
* their natural ordering
*/
@SuppressWarnings("unchecked")
public static , V> ImmutableSortedMap of(
K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
return ofEntries(entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3), entryOf(k4, v4));
}
/**
* Returns an immutable sorted map containing the given entries, sorted by the
* natural ordering of their keys.
*
* @throws IllegalArgumentException if any two keys are equal according to
* their natural ordering
*/
@SuppressWarnings("unchecked")
public static , V> ImmutableSortedMap of(
K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
return ofEntries(
entryOf(k1, v1), entryOf(k2, v2), entryOf(k3, v3), entryOf(k4, v4), entryOf(k5, v5));
}
/**
* Returns an immutable map containing the same entries as {@code map}, sorted
* by the natural ordering of the keys.
*
* Despite the method name, this method attempts to avoid actually copying
* the data when it is safe to do so. The exact circumstances under which a
* copy will or will not be performed are undocumented and subject to change.
*
*
This method is not type-safe, as it may be called on a map with keys
* that are not mutually comparable.
*
* @throws ClassCastException if the keys in {@code map} are not mutually
* comparable
* @throws NullPointerException if any key or value in {@code map} is null
* @throws IllegalArgumentException if any two keys are equal according to
* their natural ordering
*/
public static ImmutableSortedMap copyOf(Map map) {
// Hack around K not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering naturalOrder = (Ordering) NATURAL_ORDER;
return copyOfInternal(map, naturalOrder);
}
/**
* Returns an immutable map containing the same entries as {@code map}, with
* keys sorted by the provided comparator.
*
* Despite the method name, this method attempts to avoid actually copying
* the data when it is safe to do so. The exact circumstances under which a
* copy will or will not be performed are undocumented and subject to change.
*
* @throws NullPointerException if any key or value in {@code map} is null
* @throws IllegalArgumentException if any two keys are equal according to the
* comparator
*/
public static ImmutableSortedMap copyOf(
Map map, Comparator comparator) {
return copyOfInternal(map, checkNotNull(comparator));
}
/**
* Returns an immutable map containing the given entries, with keys sorted
* by the provided comparator.
*
* This method is not type-safe, as it may be called on a map with keys
* that are not mutually comparable.
*
* @throws NullPointerException if any key or value in {@code map} is null
* @throws IllegalArgumentException if any two keys are equal according to the
* comparator
* @since 19.0
*/
@Beta
public static ImmutableSortedMap copyOf(
Iterable> entries) {
// Hack around K not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering naturalOrder = (Ordering) NATURAL_ORDER;
return copyOf(entries, naturalOrder);
}
/**
* Returns an immutable map containing the given entries, with keys sorted
* by the provided comparator.
*
* @throws NullPointerException if any key or value in {@code map} is null
* @throws IllegalArgumentException if any two keys are equal according to the
* comparator
* @since 19.0
*/
@Beta
public static ImmutableSortedMap copyOf(
Iterable> entries,
Comparator comparator) {
return fromEntries(checkNotNull(comparator), false, entries);
}
/**
* Returns an immutable map containing the same entries as the provided sorted
* map, with the same ordering.
*
* Despite the method name, this method attempts to avoid actually copying
* the data when it is safe to do so. The exact circumstances under which a
* copy will or will not be performed are undocumented and subject to change.
*
* @throws NullPointerException if any key or value in {@code map} is null
*/
@SuppressWarnings("unchecked")
public static ImmutableSortedMap copyOfSorted(SortedMap map) {
Comparator comparator = map.comparator();
if (comparator == null) {
// If map has a null comparator, the keys should have a natural ordering,
// even though K doesn't explicitly implement Comparable.
comparator = (Comparator) NATURAL_ORDER;
}
if (map instanceof ImmutableSortedMap) {
// TODO(kevinb): Prove that this cast is safe, even though
// Collections.unmodifiableSortedMap requires the same key type.
@SuppressWarnings("unchecked")
ImmutableSortedMap kvMap = (ImmutableSortedMap) map;
if (!kvMap.isPartialView()) {
return kvMap;
}
}
return fromEntries(comparator, true, map.entrySet());
}
private static ImmutableSortedMap copyOfInternal(
Map map, Comparator comparator) {
boolean sameComparator = false;
if (map instanceof SortedMap) {
SortedMap sortedMap = (SortedMap) map;
Comparator comparator2 = sortedMap.comparator();
sameComparator =
(comparator2 == null)
? comparator == NATURAL_ORDER
: comparator.equals(comparator2);
}
if (sameComparator && (map instanceof ImmutableSortedMap)) {
// TODO(kevinb): Prove that this cast is safe, even though
// Collections.unmodifiableSortedMap requires the same key type.
@SuppressWarnings("unchecked")
ImmutableSortedMap kvMap = (ImmutableSortedMap) map;
if (!kvMap.isPartialView()) {
return kvMap;
}
}
return fromEntries(comparator, sameComparator, map.entrySet());
}
/**
* Accepts a collection of possibly-null entries. If {@code sameComparator}, then it is assumed
* that they do not need to be sorted or checked for dupes.
*/
private static ImmutableSortedMap fromEntries(
Comparator comparator,
boolean sameComparator,
Iterable> entries) {
// "adding" type params to an array of a raw type should be safe as
// long as no one can ever cast that same array instance back to a
// raw type.
@SuppressWarnings("unchecked")
Entry[] entryArray = (Entry[]) Iterables.toArray(entries, EMPTY_ENTRY_ARRAY);
return fromEntries(comparator, sameComparator, entryArray, entryArray.length);
}
private static ImmutableSortedMap fromEntries(
Comparator comparator,
boolean sameComparator,
Entry[] entryArray,
int size) {
switch (size) {
case 0:
return emptyMap(comparator);
case 1:
return ImmutableSortedMap.of(
comparator, entryArray[0].getKey(), entryArray[0].getValue());
default:
Object[] keys = new Object[size];
Object[] values = new Object[size];
if (sameComparator) {
// Need to check for nulls, but don't need to sort or validate.
for (int i = 0; i < size; i++) {
Object key = entryArray[i].getKey();
Object value = entryArray[i].getValue();
checkEntryNotNull(key, value);
keys[i] = key;
values[i] = value;
}
} else {
// Need to sort and check for nulls and dupes.
Arrays.sort(entryArray, 0, size, Ordering.from(comparator).onKeys());
K prevKey = entryArray[0].getKey();
keys[0] = prevKey;
values[0] = entryArray[0].getValue();
for (int i = 1; i < size; i++) {
K key = entryArray[i].getKey();
V value = entryArray[i].getValue();
checkEntryNotNull(key, value);
keys[i] = key;
values[i] = value;
checkNoConflict(
comparator.compare(prevKey, key) != 0, "key", entryArray[i - 1], entryArray[i]);
prevKey = key;
}
}
return new ImmutableSortedMap(
new RegularImmutableSortedSet(new RegularImmutableList(keys), comparator),
new RegularImmutableList(values));
}
}
/**
* Returns a builder that creates immutable sorted maps whose keys are
* ordered by their natural ordering. The sorted maps use {@link
* Ordering#natural()} as the comparator.
*/
public static , V> Builder naturalOrder() {
return new Builder(Ordering.natural());
}
/**
* Returns a builder that creates immutable sorted maps with an explicit
* comparator. If the comparator has a more general type than the map's keys,
* such as creating a {@code SortedMap} with a {@code
* Comparator}, use the {@link Builder} constructor instead.
*
* @throws NullPointerException if {@code comparator} is null
*/
public static Builder orderedBy(Comparator comparator) {
return new Builder(comparator);
}
/**
* Returns a builder that creates immutable sorted maps whose keys are
* ordered by the reverse of their natural ordering.
*/
public static , V> Builder reverseOrder() {
return new Builder(Ordering.natural().reverse());
}
/**
* A builder for creating immutable sorted map instances, especially {@code
* public static final} maps ("constant maps"). Example: {@code
*
* static final ImmutableSortedMap INT_TO_WORD =
* new ImmutableSortedMap.Builder(Ordering.natural())
* .put(1, "one")
* .put(2, "two")
* .put(3, "three")
* .build();}
*
* For small immutable sorted maps, the {@code ImmutableSortedMap.of()}
* methods are even more convenient.
*
*
Builder instances can be reused - it is safe to call {@link #build}
* multiple times to build multiple maps in series. Each map is a superset of
* the maps created before it.
*
* @since 2.0
*/
public static class Builder extends ImmutableMap.Builder {
private final Comparator comparator;
/**
* Creates a new builder. The returned builder is equivalent to the builder
* generated by {@link ImmutableSortedMap#orderedBy}.
*/
@SuppressWarnings("unchecked")
public Builder(Comparator comparator) {
this.comparator = checkNotNull(comparator);
}
/**
* Associates {@code key} with {@code value} in the built map. Duplicate
* keys, according to the comparator (which might be the keys' natural
* order), are not allowed, and will cause {@link #build} to fail.
*/
@CanIgnoreReturnValue
@Override
public Builder put(K key, V value) {
super.put(key, value);
return this;
}
/**
* Adds the given {@code entry} to the map, making it immutable if
* necessary. Duplicate keys, according to the comparator (which might be
* the keys' natural order), are not allowed, and will cause {@link #build}
* to fail.
*
* @since 11.0
*/
@CanIgnoreReturnValue
@Override
public Builder put(Entry entry) {
super.put(entry);
return this;
}
/**
* Associates all of the given map's keys and values in the built map.
* Duplicate keys, according to the comparator (which might be the keys'
* natural order), are not allowed, and will cause {@link #build} to fail.
*
* @throws NullPointerException if any key or value in {@code map} is null
*/
@CanIgnoreReturnValue
@Override
public Builder putAll(Map map) {
super.putAll(map);
return this;
}
/**
* Adds all the given entries to the built map. Duplicate keys, according
* to the comparator (which might be the keys' natural order), are not
* allowed, and will cause {@link #build} to fail.
*
* @throws NullPointerException if any key, value, or entry is null
* @since 19.0
*/
@CanIgnoreReturnValue
@Beta
@Override
public Builder putAll(Iterable> entries) {
super.putAll(entries);
return this;
}
/**
* Throws an {@code UnsupportedOperationException}.
*
* @since 19.0
* @deprecated Unsupported by ImmutableSortedMap.Builder.
*/
@CanIgnoreReturnValue
@Beta
@Override
@Deprecated
public Builder orderEntriesByValue(Comparator valueComparator) {
throw new UnsupportedOperationException("Not available on ImmutableSortedMap.Builder");
}
/**
* Returns a newly-created immutable sorted map.
*
* @throws IllegalArgumentException if any two keys are equal according to
* the comparator (which might be the keys' natural order)
*/
@Override
public ImmutableSortedMap build() {
switch (size) {
case 0:
return emptyMap(comparator);
case 1:
return of(comparator, entries[0].getKey(), entries[0].getValue());
default:
return fromEntries(comparator, false, entries, size);
}
}
}
private final transient RegularImmutableSortedSet keySet;
private final transient ImmutableList valueList;
private transient ImmutableSortedMap descendingMap;
ImmutableSortedMap(RegularImmutableSortedSet keySet, ImmutableList valueList) {
this(keySet, valueList, null);
}
ImmutableSortedMap(
RegularImmutableSortedSet keySet,
ImmutableList valueList,
ImmutableSortedMap descendingMap) {
this.keySet = keySet;
this.valueList = valueList;
this.descendingMap = descendingMap;
}
@Override
public int size() {
return valueList.size();
}
@Override
public V get(@Nullable Object key) {
int index = keySet.indexOf(key);
return (index == -1) ? null : valueList.get(index);
}
@Override
boolean isPartialView() {
return keySet.isPartialView() || valueList.isPartialView();
}
/**
* Returns an immutable set of the mappings in this map, sorted by the key
* ordering.
*/
@Override
public ImmutableSet> entrySet() {
return super.entrySet();
}
@Override
ImmutableSet> createEntrySet() {
@WeakOuter
class EntrySet extends ImmutableMapEntrySet {
@Override
public UnmodifiableIterator> iterator() {
return asList().iterator();
}
@Override
ImmutableList> createAsList() {
return new ImmutableAsList>() {
@Override
public Entry get(int index) {
return Maps.immutableEntry(keySet.asList().get(index), valueList.get(index));
}
@Override
ImmutableCollection> delegateCollection() {
return EntrySet.this;
}
};
}
@Override
ImmutableMap map() {
return ImmutableSortedMap.this;
}
}
return isEmpty() ? ImmutableSet.>of() : new EntrySet();
}
/**
* Returns an immutable sorted set of the keys in this map.
*/
@Override
public ImmutableSortedSet keySet() {
return keySet;
}
/**
* Returns an immutable collection of the values in this map, sorted by the
* ordering of the corresponding keys.
*/
@Override
public ImmutableCollection values() {
return valueList;
}
/**
* Returns the comparator that orders the keys, which is
* {@link Ordering#natural()} when the natural ordering of the keys is used.
* Note that its behavior is not consistent with {@link TreeMap#comparator()},
* which returns {@code null} to indicate natural ordering.
*/
@Override
public Comparator comparator() {
return keySet().comparator();
}
@Override
public K firstKey() {
return keySet().first();
}
@Override
public K lastKey() {
return keySet().last();
}
private ImmutableSortedMap getSubMap(int fromIndex, int toIndex) {
if (fromIndex == 0 && toIndex == size()) {
return this;
} else if (fromIndex == toIndex) {
return emptyMap(comparator());
} else {
return new ImmutableSortedMap(
keySet.getSubSet(fromIndex, toIndex), valueList.subList(fromIndex, toIndex));
}
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys are less than {@code toKey}.
*
* The {@link SortedMap#headMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code toKey}
* greater than an earlier {@code toKey}. However, this method doesn't throw
* an exception in that situation, but instead keeps the original {@code
* toKey}.
*/
@Override
public ImmutableSortedMap headMap(K toKey) {
return headMap(toKey, false);
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys are less than (or equal to, if {@code inclusive}) {@code toKey}.
*
* The {@link SortedMap#headMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code toKey}
* greater than an earlier {@code toKey}. However, this method doesn't throw
* an exception in that situation, but instead keeps the original {@code
* toKey}.
*
* @since 12.0
*/
@Override
public ImmutableSortedMap headMap(K toKey, boolean inclusive) {
return getSubMap(0, keySet.headIndex(checkNotNull(toKey), inclusive));
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys ranges from {@code fromKey}, inclusive, to {@code toKey},
* exclusive.
*
* The {@link SortedMap#subMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code
* fromKey} less than an earlier {@code fromKey}. However, this method doesn't
* throw an exception in that situation, but instead keeps the original {@code
* fromKey}. Similarly, this method keeps the original {@code toKey}, instead
* of throwing an exception, if passed a {@code toKey} greater than an earlier
* {@code toKey}.
*/
@Override
public ImmutableSortedMap subMap(K fromKey, K toKey) {
return subMap(fromKey, true, toKey, false);
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys ranges from {@code fromKey} to {@code toKey}, inclusive or
* exclusive as indicated by the boolean flags.
*
* The {@link SortedMap#subMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code
* fromKey} less than an earlier {@code fromKey}. However, this method doesn't
* throw an exception in that situation, but instead keeps the original {@code
* fromKey}. Similarly, this method keeps the original {@code toKey}, instead
* of throwing an exception, if passed a {@code toKey} greater than an earlier
* {@code toKey}.
*
* @since 12.0
*/
@Override
public ImmutableSortedMap subMap(
K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
checkNotNull(fromKey);
checkNotNull(toKey);
checkArgument(
comparator().compare(fromKey, toKey) <= 0,
"expected fromKey <= toKey but %s > %s",
fromKey,
toKey);
return headMap(toKey, toInclusive).tailMap(fromKey, fromInclusive);
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys are greater than or equals to {@code fromKey}.
*
* The {@link SortedMap#tailMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code
* fromKey} less than an earlier {@code fromKey}. However, this method doesn't
* throw an exception in that situation, but instead keeps the original {@code
* fromKey}.
*/
@Override
public ImmutableSortedMap tailMap(K fromKey) {
return tailMap(fromKey, true);
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys are greater than (or equal to, if {@code inclusive})
* {@code fromKey}.
*
* The {@link SortedMap#tailMap} documentation states that a submap of a
* submap throws an {@link IllegalArgumentException} if passed a {@code
* fromKey} less than an earlier {@code fromKey}. However, this method doesn't
* throw an exception in that situation, but instead keeps the original {@code
* fromKey}.
*
* @since 12.0
*/
@Override
public ImmutableSortedMap tailMap(K fromKey, boolean inclusive) {
return getSubMap(keySet.tailIndex(checkNotNull(fromKey), inclusive), size());
}
@Override
public Entry lowerEntry(K key) {
return headMap(key, false).lastEntry();
}
@Override
public K lowerKey(K key) {
return keyOrNull(lowerEntry(key));
}
@Override
public Entry floorEntry(K key) {
return headMap(key, true).lastEntry();
}
@Override
public K floorKey(K key) {
return keyOrNull(floorEntry(key));
}
@Override
public Entry ceilingEntry(K key) {
return tailMap(key, true).firstEntry();
}
@Override
public K ceilingKey(K key) {
return keyOrNull(ceilingEntry(key));
}
@Override
public Entry higherEntry(K key) {
return tailMap(key, false).firstEntry();
}
@Override
public K higherKey(K key) {
return keyOrNull(higherEntry(key));
}
@Override
public Entry firstEntry() {
return isEmpty() ? null : entrySet().asList().get(0);
}
@Override
public Entry lastEntry() {
return isEmpty() ? null : entrySet().asList().get(size() - 1);
}
/**
* Guaranteed to throw an exception and leave the map unmodified.
*
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@CanIgnoreReturnValue
@Deprecated
@Override
public final Entry pollFirstEntry() {
throw new UnsupportedOperationException();
}
/**
* Guaranteed to throw an exception and leave the map unmodified.
*
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@CanIgnoreReturnValue
@Deprecated
@Override
public final Entry pollLastEntry() {
throw new UnsupportedOperationException();
}
@Override
public ImmutableSortedMap descendingMap() {
// TODO(kevinb): the descendingMap is never actually cached at all. Either it should be or the
// code below simplified.
ImmutableSortedMap result = descendingMap;
if (result == null) {
if (isEmpty()) {
return result = emptyMap(Ordering.from(comparator()).reverse());
} else {
return result =
new ImmutableSortedMap(
(RegularImmutableSortedSet) keySet.descendingSet(), valueList.reverse(), this);
}
}
return result;
}
@Override
public ImmutableSortedSet navigableKeySet() {
return keySet;
}
@Override
public ImmutableSortedSet descendingKeySet() {
return keySet.descendingSet();
}
/**
* Serialized type for all ImmutableSortedMap instances. It captures the
* logical contents and they are reconstructed using public factory methods.
* This ensures that the implementation types remain as implementation
* details.
*/
private static class SerializedForm extends ImmutableMap.SerializedForm {
private final Comparator comparator;
@SuppressWarnings("unchecked")
SerializedForm(ImmutableSortedMap sortedMap) {
super(sortedMap);
comparator = (Comparator) sortedMap.comparator();
}
@Override
Object readResolve() {
Builder builder = new Builder(comparator);
return createMap(builder);
}
private static final long serialVersionUID = 0;
}
@Override
Object writeReplace() {
return new SerializedForm(this);
}
// This class is never actually serialized directly, but we have to make the
// warning go away (and suppressing would suppress for all nested classes too)
private static final long serialVersionUID = 0;
}
