@GwtCompatible(serializable=true, emulated=true) public class LinkedListMultimap<K,V> extends Object implements ListMultimap<K,V>, Serializable
ListMultimap that supports deterministic iteration order for both
keys and values. The iteration order is preserved across non-distinct key values. For example,
for the following multimap definition:
Multimap<K, V> multimap = LinkedListMultimap.create();
multimap.put(key1, foo);
multimap.put(key2, bar);
multimap.put(key1, baz);
keys() is [key1, key2, key1], and similarly for
entries(). Unlike LinkedHashMultimap, the iteration order is kept consistent
between keys, entries and values. For example, calling:
multimap.remove(key1, foo);
changes the entries iteration order to [key2=bar, key1=baz] and the key iteration
order to [key2, key1]. The entries() iterator returns mutable map entries, and
replaceValues(K, java.lang.Iterable<? extends V>) attempts to preserve iteration order as much as possible.
The collections returned by keySet() and asMap iterate through the keys in
the order they were first added to the multimap. Similarly, get(K), removeAll(java.lang.Object), and
replaceValues(K, java.lang.Iterable<? extends V>) return collections that iterate through the values in the order they were
added. The collections generated by entries(), keys(), and values()
iterate across the key-value mappings in the order they were added to the multimap.
The values() and entries() methods both return a List, instead of
the Collection specified by the ListMultimap interface.
The methods get(K), keySet(), keys(), values(), entries(), and asMap return collections that are views of the multimap. If the
multimap is modified while an iteration over any of those collections is in progress, except
through the iterator's methods, the results of the iteration are undefined.
Keys and values may be null. All optional multimap methods are supported, and all returned views are modifiable.
This class is not threadsafe when any concurrent operations update the multimap. Concurrent
read operations will work correctly. To allow concurrent update operations, wrap your multimap
with a call to Multimaps.synchronizedListMultimap(com.google.common.collect.ListMultimap<K, V>).
See the Guava User Guide article on Multimap.
| Modifier and Type | Method and Description |
|---|---|
Map<K,Collection<V>> |
asMap()
Returns a view of this multimap as a
Map from each distinct key to the nonempty
collection of that key's associated values. |
void |
clear()
Removes all key-value pairs from the multimap, leaving it empty.
|
boolean |
containsEntry(Object key,
Object value)
Returns
true if this multimap contains at least one key-value pair with the key key and the value value. |
boolean |
containsKey(Object key)
Returns
true if this multimap contains at least one key-value pair with the key key. |
boolean |
containsValue(Object value)
Returns
true if this multimap contains at least one key-value pair with the value
value. |
static <K,V> LinkedListMultimap<K,V> |
create()
Creates a new, empty
LinkedListMultimap with the default initial capacity. |
static <K,V> LinkedListMultimap<K,V> |
create(int expectedKeys)
Constructs an empty
LinkedListMultimap with enough capacity to hold the specified
number of keys without rehashing. |
static <K,V> LinkedListMultimap<K,V> |
create(Multimap<? extends K,? extends V> multimap)
Constructs a
LinkedListMultimap with the same mappings as the specified Multimap. |
List<Map.Entry<K,V>> |
entries()
Returns a view collection of all key-value pairs contained in this multimap, as
Map.Entry
instances. |
boolean |
equals(Object object)
Indicates whether some other object is "equal to" this one.
|
List<V> |
get(K key)
Returns a view collection of the values associated with
key in this multimap, if any. |
int |
hashCode()
Returns the hash code for this multimap.
|
boolean |
isEmpty()
Returns
true if this multimap contains no key-value pairs. |
Multiset<K> |
keys()
Returns a view collection containing the key from each key-value pair in this multimap,
without collapsing duplicates.
|
Set<K> |
keySet()
Returns a view collection of all distinct keys contained in this multimap.
|
boolean |
put(K key,
V value)
Stores a key-value pair in the multimap.
|
boolean |
putAll(K key,
Iterable<? extends V> values)
Stores a key-value pair in this multimap for each of
values, all using the same key,
key. |
boolean |
putAll(Multimap<? extends K,? extends V> multimap)
Stores all key-value pairs of
multimap in this multimap, in the order returned by
multimap.entries(). |
boolean |
remove(Object key,
Object value)
Removes a single key-value pair with the key
key and the value value from this
multimap, if such exists. |
List<V> |
removeAll(Object key)
Removes all values associated with the key
key. |
List<V> |
replaceValues(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key.
|
int |
size()
Returns the number of key-value pairs in this multimap.
|
String |
toString()
Returns a string representation of the multimap, generated by calling
toString on the
map returned by Multimap.asMap(). |
List<V> |
values()
Returns a view collection containing the value from each key-value pair contained in
this multimap, without collapsing duplicates (so
values().size() == size()). |
clone, finalize, getClass, notify, notifyAll, wait, wait, waitasMap, equalspublic static <K,V> LinkedListMultimap<K,V> create()
LinkedListMultimap with the default initial capacity.public static <K,V> LinkedListMultimap<K,V> create(int expectedKeys)
LinkedListMultimap with enough capacity to hold the specified
number of keys without rehashing.expectedKeys - the expected number of distinct keysIllegalArgumentException - if expectedKeys is negativepublic static <K,V> LinkedListMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
LinkedListMultimap with the same mappings as the specified Multimap. The new multimap has the same Multimap.entries() iteration order as the
input multimap.multimap - the multimap whose contents are copied to this multimappublic int size()
MultimapNote: this method does not return the number of distinct keys in the multimap,
which is given by keySet().size() or asMap().size(). See the opening section of
the Multimap class documentation for clarification.
public boolean isEmpty()
Multimaptrue if this multimap contains no key-value pairs. Equivalent to size()
== 0, but can in some cases be more efficient.public boolean containsKey(@NullableDecl Object key)
Multimaptrue if this multimap contains at least one key-value pair with the key key.containsKey in interface Multimap<K,V>public boolean containsValue(@NullableDecl Object value)
Multimaptrue if this multimap contains at least one key-value pair with the value
value.containsValue in interface Multimap<K,V>@CanIgnoreReturnValue public boolean put(@NullableDecl K key, @NullableDecl V value)
@CanIgnoreReturnValue public List<V> replaceValues(@NullableDecl K key, Iterable<? extends V> values)
If values is empty, this is equivalent to removeAll(key).
If any entries for the specified key already exist in the multimap, their values are
changed in-place without affecting the iteration order.
The returned list is immutable and implements RandomAccess.
replaceValues in interface ListMultimap<K,V>replaceValues in interface Multimap<K,V>@CanIgnoreReturnValue public List<V> removeAll(@NullableDecl Object key)
key.
Once this method returns, key will not be mapped to any values, so it will not
appear in Multimap.keySet(), Multimap.asMap(), or any other views.
Because the values for a given key may have duplicates and follow the insertion ordering,
this method returns a List, instead of the Collection specified in
the Multimap interface.
The returned list is immutable and implements RandomAccess.
public void clear()
Multimappublic List<V> get(@NullableDecl K key)
key in this multimap, if any.
Note that when containsKey(key) is false, this returns an empty collection, not null.
Changes to the returned collection will update the underlying multimap, and vice versa.
Because the values for a given key may have duplicates and follow the insertion ordering,
this method returns a List, instead of the Collection specified in
the Multimap interface.
If the multimap is modified while an iteration over the list is in progress (except through
the iterator's own add, set or remove operations) the results of the
iteration are undefined.
The returned list is not serializable and does not have random access.
public List<V> values()
values().size() == size()).
Changes to the returned collection will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
The iterator generated by the returned collection traverses the values in the order they
were added to the multimap. Because the values may have duplicates and follow the insertion
ordering, this method returns a List, instead of the Collection specified in
the ListMultimap interface.
public List<Map.Entry<K,V>> entries()
Map.Entry
instances.
Changes to the returned collection or the entries it contains will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
The iterator generated by the returned collection traverses the entries in the order they
were added to the multimap. Because the entries may have duplicates and follow the insertion
ordering, this method returns a List, instead of the Collection specified in
the ListMultimap interface.
An entry's Map.Entry.getKey() method always returns the same key, regardless of what
happens subsequently. As long as the corresponding key-value mapping is not removed from the
multimap, Map.Entry.getValue() returns the value from the multimap, which may change over
time, and Map.Entry.setValue(V) modifies that value. Removing the mapping from the multimap
does not alter the value returned by getValue(), though a subsequent setValue()
call won't update the multimap but will lead to a revised value being returned by getValue().
public boolean containsEntry(@NullableDecl Object key, @NullableDecl Object value)
Multimaptrue if this multimap contains at least one key-value pair with the key key and the value value.containsEntry in interface Multimap<K,V>@CanIgnoreReturnValue public boolean remove(@NullableDecl Object key, @NullableDecl Object value)
Multimapkey and the value value from this
multimap, if such exists. If multiple key-value pairs in the multimap fit this description,
which one is removed is unspecified.@CanIgnoreReturnValue public boolean putAll(@NullableDecl K key, Iterable<? extends V> values)
Multimapvalues, all using the same key,
key. Equivalent to (but expected to be more efficient than):
for (V value : values) {
put(key, value);
}
In particular, this is a no-op if values is empty.
@CanIgnoreReturnValue public boolean putAll(Multimap<? extends K,? extends V> multimap)
Multimapmultimap in this multimap, in the order returned by
multimap.entries().public Set<K> keySet()
MultimapChanges to the returned set will update the underlying multimap, and vice versa. However, adding to the returned set is not possible.
public Multiset<K> keys()
Multimapkeys().count(k) == get(k).size() for all k.
Changes to the returned multiset will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
public Map<K,Collection<V>> asMap()
MultimapMap from each distinct key to the nonempty
collection of that key's associated values. Note that this.asMap().get(k) is equivalent
to this.get(k) only when k is a key contained in the multimap; otherwise it
returns null as opposed to an empty collection.
Changes to the returned map or the collections that serve as its values will update the
underlying multimap, and vice versa. The map does not support put or putAll,
nor do its entries support setValue.
public boolean equals(@NullableDecl Object object)
java.lang.Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
x and y, multiple invocations of
x.equals(y) consistently return true
or consistently return false, provided no
information used in equals comparisons on the
objects is modified.
x,
x.equals(null) should return false.
The equals method for class Object implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x and
y, this method returns true if and only
if x and y refer to the same object
(x == y has the value true).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
public int hashCode()
The hash code of a multimap is defined as the hash code of the map view, as returned by
Multimap.asMap().
hashCode in interface Multimap<K,V>hashCode in class ObjectMap.hashCode()public String toString()
toString on the
map returned by Multimap.asMap().Copyright © 2010–2020. All rights reserved.