Class ImmutableMultimap<K,V>

java.lang.Object
com.google.common.collect.ImmutableMultimap<K,V>
All Implemented Interfaces:
Multimap<K,V>, Serializable
Direct Known Subclasses:
ImmutableListMultimap, ImmutableSetMultimap
@GwtCompatible(emulated=true) public abstract class ImmutableMultimap<K,V> extends Object implements Serializable
A Multimap whose contents will never change, with many other important properties detailed at ImmutableCollection.

Warning: avoid direct usage of ImmutableMultimap as a type (as with Multimap itself). Prefer subtypes such as ImmutableSetMultimap or ImmutableListMultimap, which have well-defined Multimap.equals(java.lang.Object) semantics, thus avoiding a common source of bugs and confusion.

Note: every ImmutableMultimap offers an inverse() view, so there is no need for a distinct ImmutableBiMultimap type.

Key-grouped iteration. All view collections follow the same iteration order. In all current implementations, the iteration order always keeps multiple entries with the same key together. Any creation method that would customarily respect insertion order (such as copyOf(Multimap)) instead preserves key-grouped order by inserting entries for an existing key immediately after the last entry having that key.

See the Guava User Guide article on immutable collections.

Since:
2.0
Author:
Jared Levy
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    ImmutableMultimap.Builder<K,V>
    A builder for creating immutable multimap instances, especially public static final multimaps ("constant multimaps").

  • Method Summary

    Modifier and Type
    Method
    Description
    ImmutableMap<K,Collection<V>>
    asMap()
    Returns an immutable map that associates each key with its corresponding values in the multimap.
    static <K, V> ImmutableMultimap.Builder<K,V>
    builder()
    Returns a new builder.
    static <K, V> ImmutableMultimap.Builder<K,V>
    builderWithExpectedKeys(int expectedKeys)
    Returns a new builder with a hint for how many distinct keys are expected to be added.
    final void
    clear()
    Deprecated.
    Unsupported operation.
    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.
    static <K, V> ImmutableMultimap<K,V>
    copyOf(Multimap<? extends K,? extends V> multimap)
    Returns an immutable multimap containing the same mappings as multimap, in the "key-grouped" iteration order described in the class documentation.
    static <K, V> ImmutableMultimap<K,V>
    copyOf(Iterable<? extends Map.Entry<? extends K,? extends V>> entries)
    Returns an immutable multimap containing the specified entries.
    ImmutableCollection<Map.Entry<K,V>>
    entries()
    Returns an immutable collection of all key-value pairs in the multimap.
    boolean
    equals(@Nullable Object object)
    Compares the specified object with this multimap for equality.
    void
    forEach(BiConsumer<? super K,? super V> action)
    Performs the given action for all key-value pairs contained in this multimap.
    abstract ImmutableCollection<V>
    get(K key)
    Returns an immutable collection of the values for the given key.
    int
    hashCode()
    Returns the hash code for this multimap.
    abstract ImmutableMultimap<V,K>
    inverse()
    Returns an immutable multimap which is the inverse of this one.
    boolean
    isEmpty()
    Returns true if this multimap contains no key-value pairs.
    ImmutableMultiset<K>
    keys()
    Returns an immutable multiset containing all the keys in this multimap, in the same order and with the same frequencies as they appear in this multimap; to get only a single occurrence of each key, use keySet().
    ImmutableSet<K>
    keySet()
    Returns an immutable set of the distinct keys in this multimap, in the same order as they appear in this multimap.
    static <K, V> ImmutableMultimap<K,V>
    of()
    Returns an empty multimap.
    static <K, V> ImmutableMultimap<K,V>
    of(K k1, V v1)
    Returns an immutable multimap containing a single entry.
    static <K, V> ImmutableMultimap<K,V>
    of(K k1, V v1, K k2, V v2)
    Returns an immutable multimap containing the given entries, in order.
    static <K, V> ImmutableMultimap<K,V>
    of(K k1, V v1, K k2, V v2, K k3, V v3)
    Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.
    static <K, V> ImmutableMultimap<K,V>
    of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)
    Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.
    static <K, V> ImmutableMultimap<K,V>
    of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)
    Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.
    final boolean
    put(K key, V value)
    Deprecated.
    Unsupported operation.
    final boolean
    putAll(Multimap<? extends K,? extends V> multimap)
    Deprecated.
    Unsupported operation.
    final boolean
    putAll(K key, Iterable<? extends V> values)
    Deprecated.
    Unsupported operation.
    final boolean
    remove(@Nullable Object key, @Nullable Object value)
    Deprecated.
    Unsupported operation.
    ImmutableCollection<V>
    removeAll(@Nullable Object key)
    Deprecated.
    Unsupported operation.
    ImmutableCollection<V>
    replaceValues(K key, Iterable<? extends V> values)
    Deprecated.
    Unsupported operation.
    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().
    ImmutableCollection<V>
    values()
    Returns an immutable collection of the values in this multimap.

    Methods inherited from class java.lang.Object

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

  • Method Details

    • of

      public static <K, V> ImmutableMultimap<K,V> of()
      Returns an empty multimap.

      Performance note: the instance returned is a singleton.

    • of

      public static <K, V> ImmutableMultimap<K,V> of(K k1, V v1)
      Returns an immutable multimap containing a single entry.

    • of

      public static <K, V> ImmutableMultimap<K,V> of(K k1, V v1, K k2, V v2)
      Returns an immutable multimap containing the given entries, in order.

    • of

      public static <K, V> ImmutableMultimap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3)
      Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.

    • of

      public static <K, V> ImmutableMultimap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)
      Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.

    • of

      public static <K, V> ImmutableMultimap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)
      Returns an immutable multimap containing the given entries, in the "key-grouped" insertion order described in the class documentation.

    • builder

      public static <K, V> ImmutableMultimap.Builder<K,V> builder()
      Returns a new builder. The generated builder is equivalent to the builder created by the ImmutableMultimap.Builder constructor.

    • builderWithExpectedKeys

      public static <K, V> ImmutableMultimap.Builder<K,V> builderWithExpectedKeys(int expectedKeys)
      Returns a new builder with a hint for how many distinct keys are expected to be added. The generated builder is equivalent to that returned by builder(), but may perform better if expectedKeys is a good estimate.
      Throws:
      IllegalArgumentException - if expectedKeys is negative
      Since:
      33.3.0

    • copyOf

      public static <K, V> ImmutableMultimap<K,V> copyOf(Multimap<? extends K,? extends V> multimap)
      Returns an immutable multimap containing the same mappings as multimap, in the "key-grouped" iteration order described in the class documentation.

      Despite the method name, this method attempts to avoid actually copying the data when it is safe to do so. The exact circumstances under which a copy will or will not be performed are undocumented and subject to change.

      Throws:
      NullPointerException - if any key or value in multimap is null

    • copyOf

      public static <K, V> ImmutableMultimap<K,V> copyOf(Iterable<? extends Map.Entry<? extends K,? extends V>> entries)
      Returns an immutable multimap containing the specified entries. The returned multimap iterates over keys in the order they were first encountered in the input, and the values for each key are iterated in the order they were encountered.
      Throws:
      NullPointerException - if any key, value, or entry is null
      Since:
      19.0

    • removeAll

      @CanIgnoreReturnValue @Deprecated public ImmutableCollection<V> removeAll(@Nullable Object key)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      removeAll in interface Multimap<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.
      Throws:
      UnsupportedOperationException - always

    • replaceValues

      @CanIgnoreReturnValue @Deprecated public ImmutableCollection<V> replaceValues(K key, Iterable<? extends V> values)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      replaceValues in interface Multimap<K,V>
      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.
      Throws:
      UnsupportedOperationException - always

    • clear

      @Deprecated public final void clear()
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      clear in interface Multimap<K,V>
      Throws:
      UnsupportedOperationException - always

    • get

      public abstract ImmutableCollection<V> get(K key)
      Returns an immutable collection of the values for the given key. If no mappings in the multimap have the provided key, an empty immutable collection is returned. The values are in the same order as the parameters used to build this multimap.
      Specified by:
      get in interface Multimap<K,V>

    • inverse

      public abstract ImmutableMultimap<V,K> inverse()
      Returns an immutable multimap which is the inverse of this one. For every key-value mapping in the original, the result will have a mapping with key and value reversed.
      Since:
      11.0

    • put

      @CanIgnoreReturnValue @Deprecated public final boolean put(K key, V value)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      put in interface Multimap<K,V>
      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
      Throws:
      UnsupportedOperationException - always

    • putAll

      @CanIgnoreReturnValue @Deprecated public final boolean putAll(K key, Iterable<? extends V> values)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      putAll in interface Multimap<K,V>
      Returns:
      true if the multimap changed
      Throws:
      UnsupportedOperationException - always

    • putAll

      @CanIgnoreReturnValue @Deprecated public final boolean putAll(Multimap<? extends K,? extends V> multimap)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      putAll in interface Multimap<K,V>
      Returns:
      true if the multimap changed
      Throws:
      UnsupportedOperationException - always

    • remove

      @CanIgnoreReturnValue @Deprecated public final boolean remove(@Nullable Object key, @Nullable Object value)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the multimap unmodified.
      Specified by:
      remove in interface Multimap<K,V>
      Returns:
      true if the multimap changed
      Throws:
      UnsupportedOperationException - always

    • 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,V>

    • 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,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>

    • keySet

      public ImmutableSet<K> keySet()
      Returns an immutable set of the distinct keys in this multimap, in the same order as they appear in this multimap.
      Specified by:
      keySet in interface Multimap<K,V>

    • asMap

      public ImmutableMap<K,Collection<V>> asMap()
      Returns an immutable map that associates each key with its corresponding values in the multimap. Keys and values appear in the same order as in this multimap.
      Specified by:
      asMap in interface Multimap<K,V>

    • entries

      public ImmutableCollection<Map.Entry<K,V>> entries()
      Returns an immutable collection of all key-value pairs in the multimap.
      Specified by:
      entries in interface Multimap<K,V>

    • forEach

      public void forEach(BiConsumer<? super K,? super V> action)
      Description copied from interface: Multimap
      Performs the given action for all key-value pairs contained in this multimap. If an ordering is specified by the Multimap implementation, actions will be performed in the order of iteration of Multimap.entries(). Exceptions thrown by the action are relayed to the caller.

      To loop over all keys and their associated value collections, write Multimaps.asMap(multimap).forEach((key, valueCollection) -> action()).

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

    • keys

      public ImmutableMultiset<K> keys()
      Returns an immutable multiset containing all the keys in this multimap, in the same order and with the same frequencies as they appear in this multimap; to get only a single occurrence of each key, use keySet().
      Specified by:
      keys in interface Multimap<K,V>

    • values

      public ImmutableCollection<V> values()
      Returns an immutable collection of the values in this multimap. Its iterator traverses the values for the first key, the values for the second key, and so on.
      Specified by:
      values in interface Multimap<K,V>

    • 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>

    • 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>

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