Class ImmutableMultiset<E>

All Implemented Interfaces:
Multiset<E>, Serializable, Iterable<E>, Collection<E>
Direct Known Subclasses:
ImmutableSortedMultiset

@GwtCompatible(serializable=true, emulated=true) public abstract class ImmutableMultiset<E> extends ImmutableCollection<E> implements Multiset<E>
A Multiset whose contents will never change, with many other important properties detailed at ImmutableCollection.

Grouped iteration. In all current implementations, duplicate elements always appear consecutively when iterating. Elements iterate in order by the first appearance of that element when the multiset was created.

See the Guava User Guide article on immutable collections.

Since:
2.0
See Also:
  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    A builder for creating immutable multiset instances, especially public static final multisets ("constant multisets").

    Nested classes/interfaces inherited from interface com.google.common.collect.Multiset

    Multiset.Entry<E>
  • Method Summary

    Modifier and Type
    Method
    Description
    final int
    add(E element, int occurrences)
    Deprecated.
    Unsupported operation.
    Returns an ImmutableList containing the same elements, in the same order, as this collection.
    Returns a new builder.
    boolean
    contains(Object object)
    Determines whether this multiset contains the specified element.
    static <E> ImmutableMultiset<E>
    copyOf(E[] elements)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    static <E> ImmutableMultiset<E>
    copyOf(Iterable<? extends E> elements)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    static <E> ImmutableMultiset<E>
    copyOf(Iterator<? extends E> elements)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    Returns a view of the contents of this multiset, grouped into Multiset.Entry instances, each providing an element of the multiset and the count of that element.
    boolean
    equals(Object object)
    Compares the specified object with this multiset for equality.
    int
    Returns the hash code for this multiset.
    Returns an unmodifiable iterator across the elements in this collection.
    static <E> ImmutableMultiset<E>
    of()
    Returns the empty immutable multiset.
    static <E> ImmutableMultiset<E>
    of(E element)
    Returns an immutable multiset containing a single element.
    static <E> ImmutableMultiset<E>
    of(E e1, E e2)
    Returns an immutable multiset containing the given elements, in order.
    static <E> ImmutableMultiset<E>
    of(E e1, E e2, E e3)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    static <E> ImmutableMultiset<E>
    of(E e1, E e2, E e3, E e4)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    static <E> ImmutableMultiset<E>
    of(E e1, E e2, E e3, E e4, E e5)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    static <E> ImmutableMultiset<E>
    of(E e1, E e2, E e3, E e4, E e5, E e6, E... others)
    Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
    final int
    remove(Object element, int occurrences)
    Deprecated.
    Unsupported operation.
    final int
    setCount(E element, int count)
    Deprecated.
    Unsupported operation.
    final boolean
    setCount(E element, int oldCount, int newCount)
    Deprecated.
    Unsupported operation.

    Methods inherited from class com.google.common.collect.ImmutableCollection

    add, addAll, clear, remove, removeAll, retainAll, toArray, toArray

    Methods inherited from class java.util.AbstractCollection

    containsAll, isEmpty, size

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.Collection

    addAll, clear, isEmpty, parallelStream, removeIf, size, spliterator, stream, toArray, toArray, toArray

    Methods inherited from interface java.lang.Iterable

    forEach

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

    add, containsAll, count, elementSet, remove, removeAll, retainAll
  • Method Details

    • of

      public static <E> ImmutableMultiset<E> of()
      Returns the empty immutable multiset.
    • of

      public static <E> ImmutableMultiset<E> of(E element)
      Returns an immutable multiset containing a single element.
      Throws:
      NullPointerException - if element is null
      Since:
      6.0 (source-compatible since 2.0)
    • of

      public static <E> ImmutableMultiset<E> of(E e1, E e2)
      Returns an immutable multiset containing the given elements, in order.
      Throws:
      NullPointerException - if any element is null
      Since:
      6.0 (source-compatible since 2.0)
    • of

      public static <E> ImmutableMultiset<E> of(E e1, E e2, E e3)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any element is null
      Since:
      6.0 (source-compatible since 2.0)
    • of

      public static <E> ImmutableMultiset<E> of(E e1, E e2, E e3, E e4)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any element is null
      Since:
      6.0 (source-compatible since 2.0)
    • of

      public static <E> ImmutableMultiset<E> of(E e1, E e2, E e3, E e4, E e5)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any element is null
      Since:
      6.0 (source-compatible since 2.0)
    • of

      public static <E> ImmutableMultiset<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E... others)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any element is null
      Since:
      6.0 (source-compatible since 2.0)
    • copyOf

      public static <E> ImmutableMultiset<E> copyOf(E[] elements)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any of elements is null
      Since:
      6.0
    • copyOf

      public static <E> ImmutableMultiset<E> copyOf(Iterable<? extends E> elements)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any of elements is null
    • copyOf

      public static <E> ImmutableMultiset<E> copyOf(Iterator<? extends E> elements)
      Returns an immutable multiset containing the given elements, in the "grouped iteration order" described in the class documentation.
      Throws:
      NullPointerException - if any of elements is null
    • iterator

      public UnmodifiableIterator<E> iterator()
      Description copied from class: ImmutableCollection
      Returns an unmodifiable iterator across the elements in this collection.
      Specified by:
      iterator in interface Collection<E>
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface Multiset<E>
      Specified by:
      iterator in class ImmutableCollection<E>
    • asList

      public ImmutableList<E> asList()
      Description copied from class: ImmutableCollection
      Returns an ImmutableList containing the same elements, in the same order, as this collection.

      Performance note: in most cases this method can return quickly without actually copying anything. The exact circumstances under which the copy is performed are undefined and subject to change.

      Overrides:
      asList in class ImmutableCollection<E>
    • contains

      public boolean contains(@Nullable Object object)
      Description copied from interface: Multiset
      Determines whether this multiset contains the specified element.

      This method refines Collection.contains(java.lang.Object) to further specify that it may not throw an exception in response to element being null or of the wrong type.

      Specified by:
      contains in interface Collection<E>
      Specified by:
      contains in interface Multiset<E>
      Specified by:
      contains in class ImmutableCollection<E>
      Parameters:
      object - the element to check for
      Returns:
      true if this multiset contains at least one occurrence of the element
    • add

      @Deprecated public final int add(E element, int occurrences)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the collection unmodified.
      Specified by:
      add in interface Multiset<E>
      Parameters:
      element - the element to add occurrences of; may be null only if explicitly allowed by the implementation
      occurrences - the number of occurrences of the element to add. May be zero, in which case no change will be made.
      Returns:
      the count of the element before the operation; possibly zero
      Throws:
      UnsupportedOperationException - always
    • remove

      @Deprecated public final int remove(Object element, int occurrences)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the collection unmodified.
      Specified by:
      remove in interface Multiset<E>
      Parameters:
      element - the element to conditionally remove occurrences of
      occurrences - the number of occurrences of the element to remove. May be zero, in which case no change will be made.
      Returns:
      the count of the element before the operation; possibly zero
      Throws:
      UnsupportedOperationException - always
    • setCount

      @Deprecated public final int setCount(E element, int count)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the collection unmodified.
      Specified by:
      setCount in interface Multiset<E>
      Parameters:
      element - the element to add or remove occurrences of; may be null only if explicitly allowed by the implementation
      count - the desired count of the element in this multiset
      Returns:
      the count of the element before the operation; possibly zero
      Throws:
      UnsupportedOperationException - always
    • setCount

      @Deprecated public final boolean setCount(E element, int oldCount, int newCount)
      Deprecated.
      Unsupported operation.
      Guaranteed to throw an exception and leave the collection unmodified.
      Specified by:
      setCount in interface Multiset<E>
      Parameters:
      element - the element to conditionally set the count of; may be null only if explicitly allowed by the implementation
      oldCount - the expected present count of the element in this multiset
      newCount - the desired count of the element in this multiset
      Returns:
      true if the condition for modification was met. This implies that the multiset was indeed modified, unless oldCount == newCount.
      Throws:
      UnsupportedOperationException - always
    • equals

      public boolean equals(@Nullable Object object)
      Description copied from interface: Multiset
      Compares the specified object with this multiset for equality. Returns true if the given object is also a multiset and contains equal elements with equal counts, regardless of order.
      Specified by:
      equals in interface Collection<E>
      Specified by:
      equals in interface Multiset<E>
      Overrides:
      equals in class Object
    • hashCode

      public int hashCode()
      Description copied from interface: Multiset
      Returns the hash code for this multiset. This is defined as the sum of
         
      
         ((element == null) ? 0 : element.hashCode()) ^ count(element)

      over all distinct elements in the multiset. It follows that a multiset and its entry set always have the same hash code.

      Specified by:
      hashCode in interface Collection<E>
      Specified by:
      hashCode in interface Multiset<E>
      Overrides:
      hashCode in class Object
    • toString

      public String toString()
      Description copied from interface: Multiset

      It is recommended, though not mandatory, that this method return the result of invoking Multiset.toString() on the Multiset.entrySet(), yielding a result such as [a x 3, c, d x 2, e].

      Specified by:
      toString in interface Multiset<E>
      Overrides:
      toString in class AbstractCollection<E>
    • entrySet

      public ImmutableSet<Multiset.Entry<E>> entrySet()
      Description copied from interface: Multiset
      Returns a view of the contents of this multiset, grouped into Multiset.Entry instances, each providing an element of the multiset and the count of that element. This set contains exactly one entry for each distinct element in the multiset (thus it always has the same size as the Multiset.elementSet()). The order of the elements in the element set is unspecified.

      The entry set is backed by the same data as the multiset, so any change to either is immediately reflected in the other. However, multiset changes may or may not be reflected in any Entry instances already retrieved from the entry set (this is implementation-dependent). Furthermore, implementations are not required to support modifications to the entry set at all, and the Entry instances themselves don't even have methods for modification. See the specific implementation class for more details on how its entry set handles modifications.

      Specified by:
      entrySet in interface Multiset<E>
      Returns:
      a set of entries representing the data of this multiset
    • builder

      public static <E> ImmutableMultiset.Builder<E> builder()
      Returns a new builder. The generated builder is equivalent to the builder created by the ImmutableMultiset.Builder constructor.