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com.google.common.collect
Class TreeMultimap<K,V>

java.lang.Object
  extended by com.google.common.collect.TreeMultimap<K,V>
All Implemented Interfaces:
Multimap<K,V>, SetMultimap<K,V>, SortedSetMultimap<K,V>, Serializable
@GwtCompatible(serializable=true,
               emulated=true)
public class TreeMultimap<K,V>
extends Object

Implementation of Multimap whose keys and values are ordered by their natural ordering or by supplied comparators. In all cases, this implementation uses Comparable.compareTo(T) or Comparator.compare(T, T) instead of Object.equals(java.lang.Object) to determine equivalence of instances.

Warning: The comparators or comparables used must be consistent with equals as explained by the Comparable class specification. Otherwise, the resulting multiset will violate the general contract of SetMultimap, which it is specified in terms of Object.equals(java.lang.Object).

The collections returned by keySet and asMap iterate through the keys according to the key comparator ordering or the natural ordering of the keys. Similarly, get, removeAll, and replaceValues return collections that iterate through the values according to the value comparator ordering or the natural ordering of the values. The collections generated by entries, keys, and values iterate across the keys according to the above key ordering, and for each key they iterate across the values according to the value ordering.

The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an existing key-value pair has no effect.

Depending on the comparators, null keys and values may or may not be supported. The natural ordering does not support nulls. 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.synchronizedSortedSetMultimap(com.google.common.collect.SortedSetMultimap).

Since:
2 (imported from Google Collections Library)
Author:
Jared Levy
See Also:
Serialized Form

Method Summary
 SortedMap<K,Collection<V>> asMap()
          Returns a map view that associates each key with the corresponding values in the multimap.
 void clear()
          Removes all key-value pairs from the multimap.
 boolean containsEntry(Object key, Object value)
          Returns true if the multimap contains the specified key-value pair.
 boolean containsKey(Object key)
          Returns true if the multimap contains any values for the specified key.
 boolean containsValue(Object value)
          Returns true if the multimap contains the specified value for any key.
static
<K extends Comparable,V extends Comparable>
TreeMultimap<K,V>
create()
          Creates an empty TreeMultimap ordered by the natural ordering of its keys and values.
static
<K,V> TreeMultimap<K,V>
create(Comparator<? super K> keyComparator, Comparator<? super V> valueComparator)
          Creates an empty TreeMultimap instance using explicit comparators.
static
<K extends Comparable,V extends Comparable>
TreeMultimap<K,V>
create(Multimap<? extends K,? extends V> multimap)
          Constructs a TreeMultimap, ordered by the natural ordering of its keys and values, with the same mappings as the specified multimap.
 Set<Map.Entry<K,V>> entries()
          Returns a collection of all key-value pairs.
 boolean equals(Object object)
          Compares the specified object to this multimap for equality.
 SortedSet<V> get(K key)
          Returns a collection view of all values associated with a key.
 int hashCode()
          Returns the hash code for this multimap.
 boolean isEmpty()
          Returns true if the multimap contains no key-value pairs.
 Comparator<? super K> keyComparator()
          Returns the comparator that orders the multimap keys.
 Multiset<K> keys()
          Returns a collection, which may contain duplicates, of all keys.
 SortedSet<K> keySet()
          Returns the set of all keys, each appearing once in the returned set.
 boolean put(K key, V value)
          Stores a key-value pair in the multimap.
 boolean putAll(K key, Iterable<? extends V> values)
          Stores a collection of values with the same key.
 boolean putAll(Multimap<? extends K,? extends V> multimap)
          Copies all of another multimap's key-value pairs into this multimap.
 boolean remove(Object key, Object value)
          Removes a key-value pair from the multimap.
 SortedSet<V> removeAll(Object key)
          Removes all values associated with a given key.
 SortedSet<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 the multimap.
 String toString()
          Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap().
 Comparator<? super V> valueComparator()
          Returns the comparator that orders the multimap values, with a null indicating that natural ordering is used.
 Collection<V> values()
          Returns a collection of all values in the multimap.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.google.common.collect.SetMultimap
entries, equals
 
Methods inherited from interface com.google.common.collect.Multimap
clear, containsEntry, containsKey, containsValue, hashCode, isEmpty, keys, put, putAll, putAll, remove, size
 

Method Detail

create

public static <K extends Comparable,V extends Comparable> TreeMultimap<K,V> create()
Creates an empty TreeMultimap ordered by the natural ordering of its keys and values.

create

public static <K,V> TreeMultimap<K,V> create(Comparator<? super K> keyComparator,
                                             Comparator<? super V> valueComparator)
Creates an empty TreeMultimap instance using explicit comparators. Neither comparator may be null; use Ordering.natural() to specify natural order.

Parameters:
keyComparator - the comparator that determines the key ordering
valueComparator - the comparator that determines the value ordering

create

public static <K extends Comparable,V extends Comparable> TreeMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
Constructs a TreeMultimap, ordered by the natural ordering of its keys and values, with the same mappings as the specified multimap.

Parameters:
multimap - the multimap whose contents are copied to this multimap

keyComparator

public Comparator<? super K> keyComparator()
Returns the comparator that orders the multimap keys.

valueComparator

public Comparator<? super V> valueComparator()
Description copied from interface: SortedSetMultimap
Returns the comparator that orders the multimap values, with a null indicating that natural ordering is used.

keySet

public SortedSet<K> keySet()
Returns the set of all keys, each appearing once in the returned set. Changes to the returned set will update the underlying multimap, and vice versa.

Because a TreeMultimap has unique sorted keys, this method returns a SortedSet, instead of the Set specified in the Multimap interface.

Specified by:
keySet in interface Multimap<K,V>
Returns:
the collection of distinct keys

asMap

public SortedMap<K,Collection<V>> asMap()
Returns a map view that associates each key with the corresponding values in the multimap. Changes to the returned map, such as element removal, will update the underlying multimap. The map does not support setValue() on its entries, put, or putAll.

When passed a key that is present in the map, asMap().get(Object) has the same behavior as get(K), returning a live collection. When passed a key that is not present, however, asMap().get(Object) returns null instead of an empty collection.

Though the method signature doesn't say so explicitly, the returned map has SortedSet values.

Because a TreeMultimap has unique sorted keys, this method returns a SortedMap, instead of the Map specified in the Multimap interface.

Specified by:
asMap in interface Multimap<K,V>
Specified by:
asMap in interface SetMultimap<K,V>
Specified by:
asMap in interface SortedSetMultimap<K,V>
Returns:
a map view from a key to its collection of values

get

public SortedSet<V> get(@Nullable
                        K key)
Returns a collection view of all values associated with a key. If no mappings in the multimap have the provided key, an empty collection is returned.

Changes to the returned collection will update the underlying multimap, and vice versa.

Because a SortedSetMultimap has unique sorted values for a given key, this method returns a SortedSet, instead of the Collection specified in the Multimap interface.

Specified by:
get in interface Multimap<K,V>
Specified by:
get in interface SetMultimap<K,V>
Specified by:
get in interface SortedSetMultimap<K,V>
Parameters:
key - key to search for in multimap
Returns:
the collection of values that the key maps to

removeAll

public SortedSet<V> removeAll(@Nullable
                              Object key)
Removes all values associated with a given key. The returned collection is immutable.

Because a SortedSetMultimap has unique sorted values for a given key, this method returns a SortedSet, instead of the Collection specified in the Multimap interface.

Specified by:
removeAll in interface Multimap<K,V>
Specified by:
removeAll in interface SetMultimap<K,V>
Specified by:
removeAll in interface SortedSetMultimap<K,V>
Parameters:
key - key of entries to remove from the multimap
Returns:
the collection of removed values, or an empty collection if no values were associated with the provided key. The collection may be modifiable, but updating it will have no effect on the multimap.

replaceValues

public SortedSet<V> replaceValues(K key,
                                  Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key. The returned collection is immutable.

Because a SortedSetMultimap has unique sorted values for a given key, this method returns a SortedSet, instead of the Collection specified in the Multimap interface.

Any duplicates in values will be stored in the multimap once.

Specified by:
replaceValues in interface Multimap<K,V>
Specified by:
replaceValues in interface SetMultimap<K,V>
Specified by:
replaceValues in interface SortedSetMultimap<K,V>
Parameters:
key - key to store in the multimap
values - values to store in the multimap
Returns:
the collection of replaced values, or an empty collection if no values were previously associated with the key. The collection may be modifiable, but updating it will have no effect on the multimap.

values

public Collection<V> values()
Returns a collection of all values in the multimap. Changes to the returned collection will update the underlying multimap, and vice versa.

The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on. Consequently, the values do not follow their natural ordering or the ordering of the value comparator.

Specified by:
values in interface Multimap<K,V>
Returns:
collection of values, which may include the same value multiple times if it occurs in multiple mappings

entries

public Set<Map.Entry<K,V>> entries()
Returns a collection of all key-value pairs. Changes to the returned collection will update the underlying multimap, and vice versa. The entries collection does not support the add or addAll operations.

The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.

Each entry is an immutable snapshot of a key-value mapping in the multimap, taken at the time the entry is returned by a method call to the collection or its iterator.

Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface.

Specified by:
entries in interface Multimap<K,V>
Specified by:
entries in interface SetMultimap<K,V>
Returns:
collection of map entries consisting of key-value pairs

put

public boolean put(K key,
                   V value)
Stores a key-value pair in the multimap.

Specified by:
put in interface Multimap<K,V>
Parameters:
key - key to store in the multimap
value - value to store in the multimap
Returns:
true if the method increased the size of the multimap, or false if the multimap already contained the key-value pair

equals

public boolean equals(@Nullable
                      Object object)
Compares the specified object to this multimap for equality.

Two SetMultimap instances are equal if, for each key, they contain the same values. Equality does not depend on the ordering of keys or values.

Specified by:
equals in interface Multimap<K,V>
Specified by:
equals in interface SetMultimap<K,V>
Parameters:
object - the reference object with which to compare.
Returns:
true if this object is the same as the obj argument; false otherwise.
See Also:
Object.hashCode(), Hashtable

size

public int size()
Description copied from interface: Multimap
Returns the number of key-value pairs in the multimap.

Specified by:
size in interface Multimap<K,V>

isEmpty

public boolean isEmpty()
Description copied from interface: Multimap
Returns true if the multimap contains no key-value pairs.

Specified by:
isEmpty in interface Multimap<K,V>

containsKey

public boolean containsKey(@Nullable
                           Object key)
Description copied from interface: Multimap
Returns true if the multimap contains any values for the specified key.

Specified by:
containsKey in interface Multimap<K,V>
Parameters:
key - key to search for in multimap

containsValue

public boolean containsValue(@Nullable
                             Object value)
Description copied from interface: Multimap
Returns true if the multimap contains the specified value for any key.

Specified by:
containsValue in interface Multimap<K,V>
Parameters:
value - value to search for in multimap

containsEntry

public boolean containsEntry(@Nullable
                             Object key,
                             @Nullable
                             Object value)
Description copied from interface: Multimap
Returns true if the multimap contains the specified key-value pair.

Specified by:
containsEntry in interface Multimap<K,V>
Parameters:
key - key to search for in multimap
value - value to search for in multimap

remove

public boolean remove(@Nullable
                      Object key,
                      @Nullable
                      Object value)
Description copied from interface: Multimap
Removes a key-value pair from the multimap.

Specified by:
remove in interface Multimap<K,V>
Parameters:
key - key of entry to remove from the multimap
value - value of entry to remove the multimap
Returns:
true if the multimap changed

putAll

public boolean putAll(@Nullable
                      K key,
                      Iterable<? extends V> values)
Description copied from interface: Multimap
Stores a collection of values with the same key.

Specified by:
putAll in interface Multimap<K,V>
Parameters:
key - key to store in the multimap
values - values to store in the multimap
Returns:
true if the multimap changed

putAll

public boolean putAll(Multimap<? extends K,? extends V> multimap)
Description copied from interface: Multimap
Copies all of another multimap's key-value pairs into this multimap. The order in which the mappings are added is determined by multimap.entries().

Specified by:
putAll in interface Multimap<K,V>
Parameters:
multimap - mappings to store in this multimap
Returns:
true if the multimap changed

clear

public void clear()
Description copied from interface: Multimap
Removes all key-value pairs from the multimap.

Specified by:
clear in interface Multimap<K,V>

keys

public Multiset<K> keys()
Description copied from interface: Multimap
Returns a collection, which may contain duplicates, of all keys. The number of times of key appears in the returned multiset equals the number of mappings the key has in the multimap. Changes to the returned multiset will update the underlying multimap, and vice versa.

Specified by:
keys in interface Multimap<K,V>
Returns:
a multiset with keys corresponding to the distinct keys of the multimap and frequencies corresponding to the number of values that each key maps to

hashCode

public int hashCode()
Returns the hash code for this multimap.

The hash code of a multimap is defined as the hash code of the map view, as returned by Multimap.asMap().

Specified by:
hashCode in interface Multimap<K,V>
Overrides:
hashCode in class Object
Returns:
a hash code value for this object.
See Also:
Map.hashCode()

toString

public String toString()
Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap().

Overrides:
toString in class Object
Returns:
a string representation of the multimap
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