/*
* 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.
Objects.firstNonNull;
import static com.google.common.base.
Preconditions.checkNotNull;
import static java.util.
Arrays.asList;
import com.google.common.annotations.
GwtCompatible;
import com.google.common.annotations.
GwtIncompatible;
import java.io.
IOException;
import java.io.
InvalidObjectException;
import java.io.
ObjectInputStream;
import java.io.
ObjectOutputStream;
import java.util.
Arrays;
import java.util.
Collection;
import java.util.
Collections;
import java.util.
Comparator;
import java.util.
LinkedHashMap;
import java.util.
List;
import java.util.
Map;
import java.util.
Map.
Entry;
import javax.annotation.
Nullable;
/**
* An immutable {@link SetMultimap} with reliable user-specified key and value
* iteration order. Does not permit null keys or values.
*
* <p>Unlike {@link Multimaps#unmodifiableSetMultimap(SetMultimap)}, which is
* a <i>view</i> of a separate multimap which can still change, an instance of
* {@code ImmutableSetMultimap} contains its own data and will <i>never</i>
* change. {@code ImmutableSetMultimap} is convenient for
* {@code public static final} multimaps ("constant multimaps") and also lets
* you easily make a "defensive copy" of a multimap 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 Mike Ward
* @since 2.0 (imported from Google Collections Library)
*/
@
GwtCompatible(serializable = true, emulated = true)
public class
ImmutableSetMultimap<K, V>
extends
ImmutableMultimap<K, V>
implements
SetMultimap<K, V> {
/** Returns the empty multimap. */
// Casting is safe because the multimap will never hold any elements.
@
SuppressWarnings("unchecked")
public static <K, V>
ImmutableSetMultimap<K, V>
of() {
return (
ImmutableSetMultimap<K, V>)
EmptyImmutableSetMultimap.
INSTANCE;
}
/**
* Returns an immutable multimap containing a single entry.
*/
public static <K, V>
ImmutableSetMultimap<K, V>
of(K
k1, V
v1) {
ImmutableSetMultimap.
Builder<K, V>
builder =
ImmutableSetMultimap.
builder();
builder.
put(
k1,
v1);
return
builder.
build();
}
/**
* Returns an immutable multimap containing the given entries, in order.
* Repeated occurrences of an entry (according to {@link Object#equals}) after
* the first are ignored.
*/
public static <K, V>
ImmutableSetMultimap<K, V>
of(K
k1, V
v1, K
k2, V
v2) {
ImmutableSetMultimap.
Builder<K, V>
builder =
ImmutableSetMultimap.
builder();
builder.
put(
k1,
v1);
builder.
put(
k2,
v2);
return
builder.
build();
}
/**
* Returns an immutable multimap containing the given entries, in order.
* Repeated occurrences of an entry (according to {@link Object#equals}) after
* the first are ignored.
*/
public static <K, V>
ImmutableSetMultimap<K, V>
of(
K
k1, V
v1, K
k2, V
v2, K
k3, V
v3) {
ImmutableSetMultimap.
Builder<K, V>
builder =
ImmutableSetMultimap.
builder();
builder.
put(
k1,
v1);
builder.
put(
k2,
v2);
builder.
put(
k3,
v3);
return
builder.
build();
}
/**
* Returns an immutable multimap containing the given entries, in order.
* Repeated occurrences of an entry (according to {@link Object#equals}) after
* the first are ignored.
*/
public static <K, V>
ImmutableSetMultimap<K, V>
of(
K
k1, V
v1, K
k2, V
v2, K
k3, V
v3, K
k4, V
v4) {
ImmutableSetMultimap.
Builder<K, V>
builder =
ImmutableSetMultimap.
builder();
builder.
put(
k1,
v1);
builder.
put(
k2,
v2);
builder.
put(
k3,
v3);
builder.
put(
k4,
v4);
return
builder.
build();
}
/**
* Returns an immutable multimap containing the given entries, in order.
* Repeated occurrences of an entry (according to {@link Object#equals}) after
* the first are ignored.
*/
public static <K, V>
ImmutableSetMultimap<K, V>
of(
K
k1, V
v1, K
k2, V
v2, K
k3, V
v3, K
k4, V
v4, K
k5, V
v5) {
ImmutableSetMultimap.
Builder<K, V>
builder =
ImmutableSetMultimap.
builder();
builder.
put(
k1,
v1);
builder.
put(
k2,
v2);
builder.
put(
k3,
v3);
builder.
put(
k4,
v4);
builder.
put(
k5,
v5);
return
builder.
build();
}
// looking for of() with > 5 entries? Use the builder instead.
/**
* Returns a new {@link Builder}.
*/
public static <K, V>
Builder<K, V>
builder() {
return new
Builder<K, V>();
}
/**
* Multimap for {@link ImmutableSetMultimap.Builder} that maintains key
* and value orderings and performs better than {@link LinkedHashMultimap}.
*/
private static class
BuilderMultimap<K, V> extends
AbstractMapBasedMultimap<K, V> {
BuilderMultimap() {
super(new
LinkedHashMap<K,
Collection<V>>());
}
@
Override Collection<V>
createCollection() {
return
Sets.
newLinkedHashSet();
}
private static final long
serialVersionUID = 0;
}
/**
* A builder for creating immutable {@code SetMultimap} instances, especially
* {@code public static final} multimaps ("constant multimaps"). Example:
* <pre> {@code
*
* static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP =
* new ImmutableSetMultimap.Builder<String, Integer>()
* .put("one", 1)
* .putAll("several", 1, 2, 3)
* .putAll("many", 1, 2, 3, 4, 5)
* .build();}</pre>
*
* <p>Builder instances can be reused; it is safe to call {@link #build} multiple
* times to build multiple multimaps in series. Each multimap contains the
* key-value mappings in the previously created multimaps.
*
* @since 2.0 (imported from Google Collections Library)
*/
public static final class
Builder<K, V>
extends
ImmutableMultimap.
Builder<K, V> {
/**
* Creates a new builder. The returned builder is equivalent to the builder
* generated by {@link ImmutableSetMultimap#builder}.
*/
public
Builder() {
builderMultimap = new
BuilderMultimap<K, V>();
}
/**
* Adds a key-value mapping to the built multimap if it is not already
* present.
*/
@
Override public
Builder<K, V>
put(K
key, V
value) {
builderMultimap.
put(
checkNotNull(
key),
checkNotNull(
value));
return this;
}
/**
* Adds an entry to the built multimap if it is not already present.
*
* @since 11.0
*/
@
Override public
Builder<K, V>
put(
Entry<? extends K, ? extends V>
entry) {
builderMultimap.
put(
checkNotNull(
entry.
getKey()),
checkNotNull(
entry.
getValue()));
return this;
}
@
Override public
Builder<K, V>
putAll(K
key,
Iterable<? extends V>
values) {
Collection<V>
collection =
builderMultimap.
get(
checkNotNull(
key));
for (V
value :
values) {
collection.
add(
checkNotNull(
value));
}
return this;
}
@
Override public
Builder<K, V>
putAll(K
key, V...
values) {
return
putAll(
key,
Arrays.
asList(
values));
}
@
Override public
Builder<K, V>
putAll(
Multimap<? extends K, ? extends V>
multimap) {
for (
Entry<? extends K, ? extends
Collection<? extends V>>
entry
:
multimap.
asMap().
entrySet()) {
putAll(
entry.
getKey(),
entry.
getValue());
}
return this;
}
/**
* {@inheritDoc}
*
* @since 8.0
*/
@
Override
public
Builder<K, V>
orderKeysBy(
Comparator<? super K>
keyComparator) {
this.
keyComparator =
checkNotNull(
keyComparator);
return this;
}
/**
* Specifies the ordering of the generated multimap's values for each key.
*
* <p>If this method is called, the sets returned by the {@code get()}
* method of the generated multimap and its {@link Multimap#asMap()} view
* are {@link ImmutableSortedSet} instances. However, serialization does not
* preserve that property, though it does maintain the key and value
* ordering.
*
* @since 8.0
*/
// TODO: Make serialization behavior consistent.
@
Override
public
Builder<K, V>
orderValuesBy(
Comparator<? super V>
valueComparator) {
super.orderValuesBy(
valueComparator);
return this;
}
/**
* Returns a newly-created immutable set multimap.
*/
@
Override public
ImmutableSetMultimap<K, V>
build() {
if (
keyComparator != null) {
Multimap<K, V>
sortedCopy = new
BuilderMultimap<K, V>();
List<
Map.
Entry<K,
Collection<V>>>
entries =
Lists.
newArrayList(
builderMultimap.
asMap().
entrySet());
Collections.
sort(
entries,
Ordering.
from(
keyComparator).<K>
onKeys());
for (
Map.
Entry<K,
Collection<V>>
entry :
entries) {
sortedCopy.
putAll(
entry.
getKey(),
entry.
getValue());
}
builderMultimap =
sortedCopy;
}
return
copyOf(
builderMultimap,
valueComparator);
}
}
/**
* Returns an immutable set multimap containing the same mappings as
* {@code multimap}. The generated multimap's key and value orderings
* correspond to the iteration ordering of the {@code multimap.asMap()} view.
* Repeated occurrences of an entry in the multimap after the first are
* ignored.
*
* <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 multimap} is
* null
*/
public static <K, V>
ImmutableSetMultimap<K, V>
copyOf(
Multimap<? extends K, ? extends V>
multimap) {
return
copyOf(
multimap, null);
}
private static <K, V>
ImmutableSetMultimap<K, V>
copyOf(
Multimap<? extends K, ? extends V>
multimap,
Comparator<? super V>
valueComparator) {
checkNotNull(
multimap); // eager for GWT
if (
multimap.
isEmpty() &&
valueComparator == null) {
return
of();
}
if (
multimap instanceof
ImmutableSetMultimap) {
@
SuppressWarnings("unchecked") // safe since multimap is not writable
ImmutableSetMultimap<K, V>
kvMultimap
= (
ImmutableSetMultimap<K, V>)
multimap;
if (!
kvMultimap.
isPartialView()) {
return
kvMultimap;
}
}
ImmutableMap.
Builder<K,
ImmutableSet<V>>
builder =
ImmutableMap.
builder();
int
size = 0;
for (
Entry<? extends K, ? extends
Collection<? extends V>>
entry
:
multimap.
asMap().
entrySet()) {
K
key =
entry.
getKey();
Collection<? extends V>
values =
entry.
getValue();
ImmutableSet<V>
set =
valueSet(
valueComparator,
values);
if (!
set.
isEmpty()) {
builder.
put(
key,
set);
size +=
set.
size();
}
}
return new
ImmutableSetMultimap<K, V>(
builder.
build(),
size,
valueComparator);
}
/**
* Returned by get() when a missing key is provided. Also holds the
* comparator, if any, used for values.
*/
private final transient
ImmutableSet<V>
emptySet;
ImmutableSetMultimap(
ImmutableMap<K,
ImmutableSet<V>>
map, int
size,
@
Nullable Comparator<? super V>
valueComparator) {
super(
map,
size);
this.
emptySet =
emptySet(
valueComparator);
}
// views
/**
* Returns an immutable set of the values for the given key. If no mappings
* in the multimap have the provided key, an empty immutable set is returned.
* The values are in the same order as the parameters used to build this
* multimap.
*/
@
Override public
ImmutableSet<V>
get(@
Nullable K
key) {
// This cast is safe as its type is known in constructor.
ImmutableSet<V>
set = (
ImmutableSet<V>)
map.
get(
key);
return
firstNonNull(
set,
emptySet);
}
private transient
ImmutableSetMultimap<V, K>
inverse;
/**
* {@inheritDoc}
*
* <p>Because an inverse of a set multimap cannot contain multiple pairs with
* the same key and value, this method returns an {@code ImmutableSetMultimap}
* rather than the {@code ImmutableMultimap} specified in the {@code
* ImmutableMultimap} class.
*
* @since 11.0
*/
public
ImmutableSetMultimap<V, K>
inverse() {
ImmutableSetMultimap<V, K>
result =
inverse;
return (
result == null) ? (
inverse =
invert()) :
result;
}
private
ImmutableSetMultimap<V, K>
invert() {
Builder<V, K>
builder =
builder();
for (
Entry<K, V>
entry :
entries()) {
builder.
put(
entry.
getValue(),
entry.
getKey());
}
ImmutableSetMultimap<V, K>
invertedMultimap =
builder.
build();
invertedMultimap.
inverse = this;
return
invertedMultimap;
}
/**
* Guaranteed to throw an exception and leave the multimap unmodified.
*
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@
Deprecated @
Override public
ImmutableSet<V>
removeAll(
Object key) {
throw new
UnsupportedOperationException();
}
/**
* Guaranteed to throw an exception and leave the multimap unmodified.
*
* @throws UnsupportedOperationException always
* @deprecated Unsupported operation.
*/
@
Deprecated @
Override public
ImmutableSet<V>
replaceValues(
K
key,
Iterable<? extends V>
values) {
throw new
UnsupportedOperationException();
}
private transient
ImmutableSet<
Entry<K, V>>
entries;
/**
* Returns an immutable collection of all key-value pairs in the multimap.
* Its iterator traverses the values for the first key, the values for the
* second key, and so on.
*/
@
Override public
ImmutableSet<
Entry<K, V>>
entries() {
ImmutableSet<
Entry<K, V>>
result =
entries;
return (
result == null)
? (
entries = new
EntrySet<K, V>(this))
:
result;
}
private static final class
EntrySet<K, V> extends
ImmutableSet<
Entry<K, V>> {
private transient final
ImmutableSetMultimap<K, V>
multimap;
EntrySet(
ImmutableSetMultimap<K, V>
multimap) {
this.
multimap =
multimap;
}
@
Override
public boolean
contains(@
Nullable Object object) {
if (
object instanceof
Entry) {
Entry<?, ?>
entry = (
Entry<?, ?>)
object;
return
multimap.
containsEntry(
entry.
getKey(),
entry.
getValue());
}
return false;
}
@
Override
public int
size() {
return
multimap.
size();
}
@
Override
public
UnmodifiableIterator<
Entry<K, V>>
iterator() {
return
multimap.
entryIterator();
}
@
Override
boolean
isPartialView() {
return false;
}
}
private static <V>
ImmutableSet<V>
valueSet(
@
Nullable Comparator<? super V>
valueComparator,
Collection<? extends V>
values) {
return (
valueComparator == null)
?
ImmutableSet.
copyOf(
values)
:
ImmutableSortedSet.
copyOf(
valueComparator,
values);
}
private static <V>
ImmutableSet<V>
emptySet(
@
Nullable Comparator<? super V>
valueComparator) {
return (
valueComparator == null)
?
ImmutableSet.<V>
of()
:
ImmutableSortedSet.<V>
emptySet(
valueComparator);
}
/**
* @serialData number of distinct keys, and then for each distinct key: the
* key, the number of values for that key, and the key's values
*/
@
GwtIncompatible("java.io.ObjectOutputStream")
private void
writeObject(
ObjectOutputStream stream) throws
IOException {
stream.
defaultWriteObject();
stream.
writeObject(
valueComparator());
Serialization.
writeMultimap(this,
stream);
}
@
Nullable Comparator<? super V>
valueComparator() {
return
emptySet instanceof
ImmutableSortedSet
? ((
ImmutableSortedSet<V>)
emptySet).
comparator()
: null;
}
@
GwtIncompatible("java.io.ObjectInputStream")
// Serialization type safety is at the caller's mercy.
@
SuppressWarnings("unchecked")
private void
readObject(
ObjectInputStream stream)
throws
IOException,
ClassNotFoundException {
stream.
defaultReadObject();
Comparator<
Object>
valueComparator =
(
Comparator<
Object>)
stream.
readObject();
int
keyCount =
stream.
readInt();
if (
keyCount < 0) {
throw new
InvalidObjectException("Invalid key count " +
keyCount);
}
ImmutableMap.
Builder<
Object,
ImmutableSet<
Object>>
builder
=
ImmutableMap.
builder();
int
tmpSize = 0;
for (int
i = 0;
i <
keyCount;
i++) {
Object key =
stream.
readObject();
int
valueCount =
stream.
readInt();
if (
valueCount <= 0) {
throw new
InvalidObjectException("Invalid value count " +
valueCount);
}
Object[]
array = new
Object[
valueCount];
for (int
j = 0;
j <
valueCount;
j++) {
array[
j] =
stream.
readObject();
}
ImmutableSet<
Object>
valueSet =
valueSet(
valueComparator,
asList(
array));
if (
valueSet.
size() !=
array.length) {
throw new
InvalidObjectException(
"Duplicate key-value pairs exist for key " +
key);
}
builder.
put(
key,
valueSet);
tmpSize +=
valueCount;
}
ImmutableMap<
Object,
ImmutableSet<
Object>>
tmpMap;
try {
tmpMap =
builder.
build();
} catch (
IllegalArgumentException e) {
throw (
InvalidObjectException)
new
InvalidObjectException(
e.
getMessage()).
initCause(
e);
}
FieldSettersHolder.
MAP_FIELD_SETTER.
set(this,
tmpMap);
FieldSettersHolder.
SIZE_FIELD_SETTER.
set(this,
tmpSize);
FieldSettersHolder.
EMPTY_SET_FIELD_SETTER.
set(
this,
emptySet(
valueComparator));
}
@
GwtIncompatible("not needed in emulated source.")
private static final long
serialVersionUID = 0;
}