Class ForwardingMultimap<K extends @Nullable Object,V extends @Nullable Object>

java.lang.Object
com.google.common.collect.ForwardingObject
com.google.common.collect.ForwardingMultimap<K,V>
All Implemented Interfaces:
Multimap<K,V>
Direct Known Subclasses:
ForwardingListMultimap, ForwardingSetMultimap
@GwtCompatible public abstract class ForwardingMultimap<K extends @Nullable Object,V extends @Nullable Object> extends ForwardingObject implements Multimap<K,V>
A multimap which forwards all its method calls to another multimap. Subclasses should override one or more methods to modify the behavior of the backing multimap as desired per the decorator pattern.

default method warning: This class does not forward calls to default methods. Instead, it inherits their default implementations. When those implementations invoke methods, they invoke methods on the ForwardingMultimap.

Since:
2.0
Author:
Robert Konigsberg

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    ForwardingMultimap()
    Constructor for use by subclasses.

  • 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(@Nullable Object key, @Nullable Object value)
    Returns true if this multimap contains at least one key-value pair with the key key and the value value.
    boolean
    containsKey(@Nullable Object key)
    Returns true if this multimap contains at least one key-value pair with the key key.
    boolean
    containsValue(@Nullable Object value)
    Returns true if this multimap contains at least one key-value pair with the value value.
    protected abstract Multimap<K,V>
    delegate()
    Returns the backing delegate instance that methods are forwarded to.
    Collection<Map.Entry<K,V>>
    entries()
    Returns a view collection of all key-value pairs contained in this multimap, as Map.Entry instances.
    boolean
    equals(@Nullable Object object)
    Compares the specified object with this multimap for equality.
    Collection<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 this multimap.
    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
    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(@Nullable Object key, @Nullable Object value)
    Removes a single key-value pair with the key key and the value value from this multimap, if such exists.
    Collection<V>
    removeAll(@Nullable Object key)
    Removes all values associated with the key key.
    Collection<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.
    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 com.google.common.collect.ForwardingObject

    toString

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface com.google.common.collect.Multimap

    forEach

  • Constructor Details

  • Method Details

    • delegate

      protected abstract Multimap<K,V> delegate()
      Description copied from class: ForwardingObject
      Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
      Specified by:
      delegate in class ForwardingObject

    • asMap

      public Map<K,Collection<V>> asMap()
      Description copied from interface: Multimap
      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.

      Specified by:
      asMap in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • 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 extends @Nullable Object,V extends @Nullable Object>

    • containsEntry

      public boolean containsEntry(@Nullable Object key, @Nullable 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 extends @Nullable Object,V extends @Nullable Object>

    • containsKey

      public boolean containsKey(@Nullable 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 extends @Nullable Object,V extends @Nullable Object>

    • containsValue

      public boolean containsValue(@Nullable 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 extends @Nullable Object,V extends @Nullable Object>

    • entries

      public Collection<Map.Entry<K,V>> entries()
      Description copied from interface: Multimap
      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.

      Specified by:
      entries in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • get

      public Collection<V> get(K key)
      Description copied from interface: Multimap
      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.

      Specified by:
      get in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: Multimap
      Returns true if this multimap contains no key-value pairs. Equivalent to size() == 0, but can in some cases be more efficient.
      Specified by:
      isEmpty in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • keys

      public Multiset<K> keys()
      Description copied from interface: Multimap
      Returns a view collection containing the key from each key-value pair in this multimap, without collapsing duplicates. This collection has the same size as this multimap, and keys().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.

      Specified by:
      keys in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • 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 extends @Nullable Object,V extends @Nullable Object>

    • put

      @CanIgnoreReturnValue public boolean put(K key, V value)
      Description copied from interface: Multimap
      Stores a key-value pair in this multimap.

      Some multimap implementations allow duplicate key-value pairs, in which case put always adds a new key-value pair and increases the multimap size by 1. Other implementations prohibit duplicates, and storing a key-value pair that's already in the multimap has no effect.

      Specified by:
      put in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>
      Returns:
      true if the method increased the size of the multimap, or false if the multimap already contained the key-value pair and doesn't allow duplicates

    • putAll

      @CanIgnoreReturnValue 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): 
      
 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 extends @Nullable Object,V extends @Nullable Object>
      Returns:
      true if the multimap changed

    • putAll

      @CanIgnoreReturnValue public boolean putAll(Multimap<? extends K,? extends V> multimap)
      Description copied from interface: Multimap
      Stores all key-value pairs of multimap in this multimap, in the order returned by multimap.entries().
      Specified by:
      putAll in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>
      Returns:
      true if the multimap changed

    • remove

      @CanIgnoreReturnValue public boolean remove(@Nullable Object key, @Nullable 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 extends @Nullable Object,V extends @Nullable Object>
      Returns:
      true if the multimap changed

    • removeAll

      @CanIgnoreReturnValue public Collection<V> removeAll(@Nullable Object key)
      Description copied from interface: Multimap
      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.

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

    • replaceValues

      @CanIgnoreReturnValue public Collection<V> replaceValues(K key, Iterable<? extends V> values)
      Description copied from interface: Multimap
      Stores a collection of values with the same key, replacing any existing values for that key.

      If values is empty, this is equivalent to removeAll(key).

      Specified by:
      replaceValues in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>
      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.

    • 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 extends @Nullable Object,V extends @Nullable Object>

    • values

      public Collection<V> values()
      Description copied from interface: Multimap
      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.

      Specified by:
      values in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>

    • equals

      public boolean equals(@Nullable Object object)
      Description copied from interface: Multimap
      Compares the specified object with this multimap for equality. Two multimaps are equal when their map views, as returned by Multimap.asMap(), are also equal.

      In general, two multimaps with identical key-value mappings may or may not be equal, depending on the implementation. For example, two SetMultimap instances with the same key-value mappings are equal, but equality of two ListMultimap instances depends on the ordering of the values for each key.

      A non-empty SetMultimap cannot be equal to a non-empty ListMultimap, since their Multimap.asMap() views contain unequal collections as values. However, any two empty multimaps are equal, because they both have empty Multimap.asMap() views.

      Specified by:
      equals in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Description copied from interface: Multimap
      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().

      In general, two multimaps with identical key-value mappings may or may not have the same hash codes, depending on the implementation. For example, two SetMultimap instances with the same key-value mappings will have the same hashCode, but the hashCode of ListMultimap instances depends on the ordering of the values for each key.

      Specified by:
      hashCode in interface Multimap<K extends @Nullable Object,V extends @Nullable Object>
      Overrides:
      hashCode in class Object