Class Multisets.UnmodifiableMultiset<E>

All Implemented Interfaces:
Multiset<E>, Serializable, Iterable<E>, Collection<E>
Direct Known Subclasses:
UnmodifiableSortedMultiset
Enclosing class:
Multisets

static class Multisets.UnmodifiableMultiset<E> extends ForwardingMultiset<E> implements Serializable
  • Field Details

    • delegate

      final Multiset<? extends E> delegate
    • elementSet

      @CheckForNull transient Set<E> elementSet
    • entrySet

      @CheckForNull transient Set<Multiset.Entry<E>> entrySet
    • serialVersionUID

      private static final long serialVersionUID
      See Also:
  • Constructor Details

    • UnmodifiableMultiset

      UnmodifiableMultiset(Multiset<? extends E> delegate)
  • Method Details

    • delegate

      protected Multiset<E> 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 ForwardingMultiset<E>
    • createElementSet

      Set<E> createElementSet()
    • elementSet

      public Set<E> elementSet()
      Description copied from interface: Multiset
      Returns the set of distinct elements contained in this multiset. The element set is backed by the same data as the multiset, so any change to either is immediately reflected in the other. The order of the elements in the element set is unspecified.

      If the element set supports any removal operations, these necessarily cause all occurrences of the removed element(s) to be removed from the multiset. Implementations are not expected to support the add operations, although this is possible.

      A common use for the element set is to find the number of distinct elements in the multiset: elementSet().size().

      Specified by:
      elementSet in interface Multiset<E>
      Overrides:
      elementSet in class ForwardingMultiset<E>
      Returns:
      a view of the set of distinct elements in this multiset
    • entrySet

      public Set<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>
      Overrides:
      entrySet in class ForwardingMultiset<E>
      Returns:
      a set of entries representing the data of this multiset
    • iterator

      public Iterator<E> iterator()
      Description copied from interface: Multiset

      Elements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.

      Specified by:
      iterator in interface Collection<E>
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface Multiset<E>
      Overrides:
      iterator in class ForwardingCollection<E>
    • add

      public boolean add(E element)
      Description copied from interface: Multiset
      Adds a single occurrence of the specified element to this multiset.

      This method refines Collection.add(E), which only ensures the presence of the element, to further specify that a successful call must always increment the count of the element, and the overall size of the collection, by one.

      To both add the element and obtain the previous count of that element, use add(element, 1) instead.

      Specified by:
      add in interface Collection<E>
      Specified by:
      add in interface Multiset<E>
      Overrides:
      add in class ForwardingCollection<E>
      Parameters:
      element - the element to add one occurrence of; may be null only if explicitly allowed by the implementation
      Returns:
      true always, since this call is required to modify the multiset, unlike other Collection types
    • add

      public int add(E element, int occurrences)
      Description copied from interface: Multiset
      Adds a number of occurrences of an element to this multiset. Note that if occurrences == 1, this method has the identical effect to Multiset.add(Object). This method is functionally equivalent (except in the case of overflow) to the call addAll(Collections.nCopies(element, occurrences)), which would presumably perform much more poorly.
      Specified by:
      add in interface Multiset<E>
      Overrides:
      add in class ForwardingMultiset<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
    • addAll

      public boolean addAll(Collection<? extends E> elementsToAdd)
      Specified by:
      addAll in interface Collection<E>
      Overrides:
      addAll in class ForwardingCollection<E>
    • remove

      public boolean remove(@CheckForNull Object element)
      Description copied from interface: Multiset
      Removes a single occurrence of the specified element from this multiset, if present.

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

      To both remove the element and obtain the previous count of that element, use remove(element, 1) instead.

      Specified by:
      remove in interface Collection<E>
      Specified by:
      remove in interface Multiset<E>
      Overrides:
      remove in class ForwardingCollection<E>
      Parameters:
      element - the element to remove one occurrence of
      Returns:
      true if an occurrence was found and removed
    • remove

      public int remove(@CheckForNull Object element, int occurrences)
      Description copied from interface: Multiset
      Removes a number of occurrences of the specified element from this multiset. If the multiset contains fewer than this number of occurrences to begin with, all occurrences will be removed. Note that if occurrences == 1, this is functionally equivalent to the call remove(element).
      Specified by:
      remove in interface Multiset<E>
      Overrides:
      remove in class ForwardingMultiset<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
    • removeAll

      public boolean removeAll(Collection<?> elementsToRemove)
      Description copied from interface: Multiset

      Note: This method ignores how often any element might appear in c, and only cares whether or not an element appears at all. If you wish to remove one occurrence in this multiset for every occurrence in c, see Multisets.removeOccurrences(Multiset, Multiset).

      This method refines Collection.removeAll(java.util.Collection<?>) to further specify that it may not throw an exception in response to any of elements being null or of the wrong type.

      Specified by:
      removeAll in interface Collection<E>
      Specified by:
      removeAll in interface Multiset<E>
      Overrides:
      removeAll in class ForwardingCollection<E>
    • removeIf

      public boolean removeIf(Predicate<? super E> filter)
      Specified by:
      removeIf in interface Collection<E>
    • retainAll

      public boolean retainAll(Collection<?> elementsToRetain)
      Description copied from interface: Multiset

      Note: This method ignores how often any element might appear in c, and only cares whether or not an element appears at all. If you wish to remove one occurrence in this multiset for every occurrence in c, see Multisets.retainOccurrences(Multiset, Multiset).

      This method refines Collection.retainAll(java.util.Collection<?>) to further specify that it may not throw an exception in response to any of elements being null or of the wrong type.

      Specified by:
      retainAll in interface Collection<E>
      Specified by:
      retainAll in interface Multiset<E>
      Overrides:
      retainAll in class ForwardingCollection<E>
      See Also:
    • clear

      public void clear()
      Specified by:
      clear in interface Collection<E>
      Overrides:
      clear in class ForwardingCollection<E>
    • setCount

      public int setCount(E element, int count)
      Description copied from interface: Multiset
      Adds or removes the necessary occurrences of an element such that the element attains the desired count.
      Specified by:
      setCount in interface Multiset<E>
      Overrides:
      setCount in class ForwardingMultiset<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
    • setCount

      public boolean setCount(E element, int oldCount, int newCount)
      Description copied from interface: Multiset
      Conditionally sets the count of an element to a new value, as described in Multiset.setCount(Object, int), provided that the element has the expected current count. If the current count is not oldCount, no change is made.
      Specified by:
      setCount in interface Multiset<E>
      Overrides:
      setCount in class ForwardingMultiset<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.