Package org.glassfish.jersey.internal.guava

Class HashMultimap<K,V>

java.lang.Object
org.glassfish.jersey.internal.guava.HashMultimap<K,V>
All Implemented Interfaces:
Serializable, Multimap<K,V>, SetMultimap<K,V>
public final class HashMultimap<K,V> extends Object
Implementation of Multimap using hash tables.

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.

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#synchronizedSetMultimap.

Since:
2.0 (imported from Google Collections Library)
Author:
Jared Levy
See Also:

  • Method Summary

    Modifier and Type
    Method
    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> HashMultimap<K,V>
    create()
    Creates a new, empty HashMultimap with the default initial capacities.
    Set<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)
    Compares the specified object to this multimap for equality.
    Set<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.
    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
    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.
    Set<V>
    removeAll(Object key)
    Removes all values associated with the key 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().
    Collection<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()).

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    Methods inherited from interface org.glassfish.jersey.internal.guava.Multimap

    clear, containsEntry, containsKey, containsValue, hashCode, keySet, putAll, remove, size, values

  • Method Details

    • create

      public static <K, V> HashMultimap<K,V> create()
      Creates a new, empty HashMultimap with the default initial capacities.

    • get

      public Set<V> get(K key)
      Returns a view collection of the values associated with 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.

      The returned collection is not serializable.

      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:
      get in interface Multimap<K,V>
      Specified by:
      get in interface SetMultimap<K,V>

    • entries

      public Set<Map.Entry<K,V>> entries()
      Returns a view collection of all key-value pairs contained in this multimap, as 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 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>

    • removeAll

      public Set<V> removeAll(Object key)
      Removes all values associated with the 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.

      The returned collection is immutable.

      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:
      removeAll in interface Multimap<K,V>
      Specified by:
      removeAll in interface SetMultimap<K,V>
      Returns:
      the values that were removed (possibly empty). The returned collection may be modifiable, but updating it will have no effect on the multimap.

    • asMap

      public 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. 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.

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

      Specified by:
      asMap in interface Multimap<K,V>
      Specified by:
      asMap in interface SetMultimap<K,V>

    • 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(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>

    • size

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

      Note: 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.

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

    • containsKey

      public boolean containsKey(Object key)
      Description copied from interface: Multimap
      Returns true if this multimap contains at least one key-value pair with the key key.
      Specified by:
      containsKey in interface Multimap<K,V>

    • clear

      public void clear()
      Description copied from interface: Multimap
      Removes all key-value pairs from the multimap, leaving it empty.
      Specified by:
      clear in interface Multimap<K,V>

    • values

      public Collection<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()).

      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 for one key, followed by the values of a second key, and so on.

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

    • containsValue

      public boolean containsValue(Object value)
      Description copied from interface: Multimap
      Returns true if this multimap contains at least one key-value pair with the value value.
      Specified by:
      containsValue in interface Multimap<K,V>

    • containsEntry

      public boolean containsEntry(Object key, Object value)
      Description copied from interface: Multimap
      Returns true if this multimap contains at least one key-value pair with the key key and the value value.
      Specified by:
      containsEntry in interface Multimap<K,V>

    • remove

      public boolean remove(Object key, Object value)
      Description copied from interface: Multimap
      Removes a single key-value pair with the key key 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.
      Specified by:
      remove in interface Multimap<K,V>
      Returns:
      true if the multimap changed

    • putAll

      public boolean putAll(K key, Iterable<? extends V> values)
      Description copied from interface: Multimap
      Stores a key-value pair in this multimap for each of values, all using the same key, key. Equivalent to (but expected to be more efficient than): 
         
 <p>
   for (V value : values) {
     put(key, value);
   }

      In particular, this is a no-op if values is empty.

      Specified by:
      putAll in interface Multimap<K,V>
      Returns:
      true if the multimap changed

    • keySet

      public Set<K> keySet()
      Description copied from interface: Multimap
      Returns a view collection of all distinct keys contained in this multimap. Note that the key set contains a key if and only if this multimap maps that key to at least one value.

      Changes to the returned set will update the underlying multimap, and vice versa. However, adding to the returned set is not possible.

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

    • 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
      See Also:

    • 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