/*
* 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.Maps.keyOrNull;
import com.google.common.annotations.GwtCompatible;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import javax.annotation.Nullable;
/**
* An immutable {@link SortedMap}. Does not permit null keys or values.
*
* <p>Unlike {@link Collections#unmodifiableSortedMap}, which is a <i>view</i>
* of a separate map which can still change, an instance of {@code
* ImmutableSortedMap} contains its own data and will <i>never</i> change.
* {@code ImmutableSortedMap} is convenient for {@code public static final} maps
* ("constant maps") and also lets you easily make a "defensive copy" of a map
* provided to your class by a caller.
*
* <p><b>Note:</b> Although this class is not final, it cannot be subclassed as
* it has no public or protected constructors. Thus, instances of this class are
* guaranteed to be immutable.
*
* <p>See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/ImmutableCollectionsExplained">
* immutable collections</a>.
*
* @author Jared Levy
* @author Louis Wasserman
* @since 2.0 (imported from Google Collections Library; implements {@code
* NavigableMap} since 12.0)
*/
@GwtCompatible(serializable = true, emulated = true)
public abstract class ImmutableSortedMap<K, V>
extends ImmutableSortedMapFauxverideShim<K, V> implements NavigableMap<K, V> {
/*
* 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<Comparable> NATURAL_ORDER = Ordering.natural();
private static final ImmutableSortedMap<Comparable, Object> NATURAL_EMPTY_MAP =
new EmptyImmutableSortedMap<Comparable, Object>(NATURAL_ORDER);
static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {
if (Ordering.natural().equals(comparator)) {
return of();
} else {
return new EmptyImmutableSortedMap<K, V>(comparator);
}
}
static <K, V> ImmutableSortedMap<K, V> fromSortedEntries(
Comparator<? super K> comparator,
int size,
Entry<K, V>[] entries) {
if (size == 0) {
return emptyMap(comparator);
}
ImmutableList.Builder<K> keyBuilder = ImmutableList.builder();
ImmutableList.Builder<V> valueBuilder = ImmutableList.builder();
for (int i = 0; i < size; i++) {
Entry<K, V> entry = entries[i];
keyBuilder.add(entry.getKey());
valueBuilder.add(entry.getValue());
}
return new RegularImmutableSortedMap<K, V>(
new RegularImmutableSortedSet<K>(keyBuilder.build(), comparator),
valueBuilder.build());
}
static <K, V> ImmutableSortedMap<K, V> from(
ImmutableSortedSet<K> keySet, ImmutableList<V> valueList) {
if (keySet.isEmpty()) {
return emptyMap(keySet.comparator());
} else {
return new RegularImmutableSortedMap<K, V>(
(RegularImmutableSortedSet<K>) keySet,
valueList);
}
}
/**
* 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 <K, V> ImmutableSortedMap<K, V> of() {
return (ImmutableSortedMap<K, V>) NATURAL_EMPTY_MAP;
}
/**
* Returns an immutable map containing a single entry.
*/
public static <K extends Comparable<? super K>, V>
ImmutableSortedMap<K, V> of(K k1, V v1) {
return from(ImmutableSortedSet.of(k1), ImmutableList.of(v1));
}
/**
* 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 <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V>
of(K k1, V v1, K k2, V v2) {
return fromEntries(Ordering.natural(), false, 2, 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 <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V>
of(K k1, V v1, K k2, V v2, K k3, V v3) {
return fromEntries(Ordering.natural(), false, 3, 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 <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V>
of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
return fromEntries(Ordering.natural(), false, 4, 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 <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V>
of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
return fromEntries(Ordering.natural(), false, 5, 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.
*
* <p>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.
*
* <p>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 <K, V> ImmutableSortedMap<K, V> copyOf(
Map<? extends K, ? extends V> map) {
// Hack around K not being a subtype of Comparable.
// Unsafe, see ImmutableSortedSetFauxverideShim.
@SuppressWarnings("unchecked")
Ordering<K> naturalOrder = (Ordering<K>) Ordering.<Comparable>natural();
return copyOfInternal(map, naturalOrder);
}
/**
* Returns an immutable map containing the same entries as {@code map}, with
* keys sorted by the provided comparator.
*
* <p>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 <K, V> ImmutableSortedMap<K, V> copyOf(
Map<? extends K, ? extends V> map, Comparator<? super K> comparator) {
return copyOfInternal(map, checkNotNull(comparator));
}
/**
* Returns an immutable map containing the same entries as the provided sorted
* map, with the same ordering.
*
* <p>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 <K, V> ImmutableSortedMap<K, V> copyOfSorted(
SortedMap<K, ? extends V> map) {
Comparator<? super K> 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<? super K>) NATURAL_ORDER;
}
return copyOfInternal(map, comparator);
}
private static <K, V> ImmutableSortedMap<K, V> copyOfInternal(
Map<? extends K, ? extends V> map, Comparator<? super K> 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<K, V> kvMap = (ImmutableSortedMap<K, V>) map;
if (!kvMap.isPartialView()) {
return kvMap;
}
}
// "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<K, V>[] entries = map.entrySet().toArray(new Entry[0]);
return fromEntries(comparator, sameComparator, entries.length, entries);
}
static <K, V> ImmutableSortedMap<K, V> fromEntries(
Comparator<? super K> comparator, boolean sameComparator, int size, Entry<K, V>... entries) {
for (int i = 0; i < size; i++) {
Entry<K, V> entry = entries[i];
entries[i] = entryOf(entry.getKey(), entry.getValue());
}
if (!sameComparator) {
sortEntries(comparator, size, entries);
validateEntries(size, entries, comparator);
}
return fromSortedEntries(comparator, size, entries);
}
private static <K, V> void sortEntries(
final Comparator<? super K> comparator, int size, Entry<K, V>[] entries) {
Arrays.sort(entries, 0, size, Ordering.from(comparator).<K>onKeys());
}
private static <K, V> void validateEntries(int size, Entry<K, V>[] entries,
Comparator<? super K> comparator) {
for (int i = 1; i < size; i++) {
checkNoConflict(comparator.compare(entries[i - 1].getKey(), entries[i].getKey()) != 0, "key",
entries[i - 1], entries[i]);
}
}
/**
* 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 <K extends Comparable<?>, V> Builder<K, V> naturalOrder() {
return new Builder<K, V>(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<Integer, String>} with a {@code
* Comparator<Number>}, use the {@link Builder} constructor instead.
*
* @throws NullPointerException if {@code comparator} is null
*/
public static <K, V> Builder<K, V> orderedBy(Comparator<K> comparator) {
return new Builder<K, V>(comparator);
}
/**
* Returns a builder that creates immutable sorted maps whose keys are
* ordered by the reverse of their natural ordering.
*/
public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
return new Builder<K, V>(Ordering.natural().reverse());
}
/**
* A builder for creating immutable sorted map instances, especially {@code
* public static final} maps ("constant maps"). Example: <pre> {@code
*
* static final ImmutableSortedMap<Integer, String> INT_TO_WORD =
* new ImmutableSortedMap.Builder<Integer, String>(Ordering.natural())
* .put(1, "one")
* .put(2, "two")
* .put(3, "three")
* .build();}</pre>
*
* <p>For <i>small</i> immutable sorted maps, the {@code ImmutableSortedMap.of()}
* methods are even more convenient.
*
* <p>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 (imported from Google Collections Library)
*/
public static class Builder<K, V> extends ImmutableMap.Builder<K, V> {
private final Comparator<? super K> comparator;
/**
* Creates a new builder. The returned builder is equivalent to the builder
* generated by {@link ImmutableSortedMap#orderedBy}.
*/
@SuppressWarnings("unchecked")
public Builder(Comparator<? super K> 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.
*/
@Override public Builder<K, V> 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
*/
@Override public Builder<K, V> put(Entry<? extends K, ? extends V> 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
*/
@Override public Builder<K, V> putAll(Map<? extends K, ? extends V> map) {
super.putAll(map);
return this;
}
/**
* 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<K, V> build() {
return fromEntries(comparator, false, size, entries);
}
}
ImmutableSortedMap() {
}
ImmutableSortedMap(ImmutableSortedMap<K, V> descendingMap) {
this.descendingMap = descendingMap;
}
@Override
public int size() {
return values().size();
}
@Override public boolean containsValue(@Nullable Object value) {
return values().contains(value);
}
@Override boolean isPartialView() {
return keySet().isPartialView() || values().isPartialView();
}
/**
* Returns an immutable set of the mappings in this map, sorted by the key
* ordering.
*/
@Override public ImmutableSet<Entry<K, V>> entrySet() {
return super.entrySet();
}
/**
* Returns an immutable sorted set of the keys in this map.
*/
@Override public abstract ImmutableSortedSet<K> keySet();
/**
* Returns an immutable collection of the values in this map, sorted by the
* ordering of the corresponding keys.
*/
@Override public abstract ImmutableCollection<V> values();
/**
* 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<? super K> comparator() {
return keySet().comparator();
}
@Override
public K firstKey() {
return keySet().first();
}
@Override
public K lastKey() {
return keySet().last();
}
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys are less than {@code toKey}.
*
* <p>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<K, V> 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}.
*
* <p>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 abstract ImmutableSortedMap<K, V> headMap(K toKey, boolean inclusive);
/**
* This method returns a {@code ImmutableSortedMap}, consisting of the entries
* whose keys ranges from {@code fromKey}, inclusive, to {@code toKey},
* exclusive.
*
* <p>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<K, V> 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.
*
* <p>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<K, V> 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}.
*
* <p>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<K, V> 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}.
*
* <p>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 abstract ImmutableSortedMap<K, V> tailMap(K fromKey, boolean inclusive);
@Override
public Entry<K, V> lowerEntry(K key) {
return headMap(key, false).lastEntry();
}
@Override
public K lowerKey(K key) {
return keyOrNull(lowerEntry(key));
}
@Override
public Entry<K, V> floorEntry(K key) {
return headMap(key, true).lastEntry();
}
@Override
public K floorKey(K key) {
return keyOrNull(floorEntry(key));
}
@Override
public Entry<K, V> ceilingEntry(K key) {
return tailMap(key, true).firstEntry();
}
@Override
public K ceilingKey(K key) {
return keyOrNull(ceilingEntry(key));
}
@Override
public Entry<K, V> higherEntry(K key) {
return tailMap(key, false).firstEntry();
}
@Override
public K higherKey(K key) {
return keyOrNull(higherEntry(key));
}
@Override
public Entry<K, V> firstEntry() {
return isEmpty() ? null : entrySet().asList().get(0);
}
@Override
public Entry<K, V> 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.
*/
@Deprecated
@Override
public final Entry<K, V> pollFirstEntry() {
throw new UnsupportedOperationException();
}
/**
* Guaranteed to throw an exception and leave the map unmodified.
*
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@Deprecated
@Override
public final Entry<K, V> pollLastEntry() {
throw new UnsupportedOperationException();
}
private transient ImmutableSortedMap<K, V> descendingMap;
@Override
public ImmutableSortedMap<K, V> descendingMap() {
ImmutableSortedMap<K, V> result = descendingMap;
if (result == null) {
result = descendingMap = createDescendingMap();
}
return result;
}
abstract ImmutableSortedMap<K, V> createDescendingMap();
@Override
public ImmutableSortedSet<K> navigableKeySet() {
return keySet();
}
@Override
public ImmutableSortedSet<K> 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<Object> comparator;
@SuppressWarnings("unchecked")
SerializedForm(ImmutableSortedMap<?, ?> sortedMap) {
super(sortedMap);
comparator = (Comparator<Object>) sortedMap.comparator();
}
@Override Object readResolve() {
Builder<Object, Object> builder = new Builder<Object, Object>(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;
}