@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);
... the iteration order for 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:
map.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(@Nullable 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(@Nullable Object value)
Multimaptrue if this multimap contains at least one key-value pair
with the value value.containsValue in interface Multimap<K,V>public List<V> replaceValues(@Nullable 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>public List<V> removeAll(@Nullable 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(@Nullable 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(@Nullable Object key, @Nullable 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>public boolean remove(@Nullable Object key, @Nullable 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.public boolean putAll(@Nullable 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.
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(@Nullable 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 © 2010–2017. All rights reserved.