MultiSet ("The Adobe AEM Quickstart and Web Application.")

Type Parameters:

E - the type held in the multiset

All Superinterfaces:

java.util.Collection<E>, java.lang.Iterable<E>

All Known Implementing Classes:

AbstractMapMultiSet, AbstractMultiSet, AbstractMultiSetDecorator, HashMultiSet, PredicatedMultiSet, SynchronizedMultiSet, UnmodifiableMultiSet
```
public interface MultiSet<E>
extends java.util.Collection<E>
```
Defines a collection that counts the number of times an object appears in the collection.
Suppose you have a MultiSet that contains {a, a, b, c}. Calling getCount(Object) on a would return 2, while calling uniqueSet() would return {a, b, c}.

Since:

4.1

Nested Class Summary

Nested Classes
Modifier and Type Interface and Description

static interface MultiSet.Entry<E>
An unmodifiable entry for an element and its occurrence as contained in a MultiSet.

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`MultiSet.Entry<E>` An unmodifiable entry for an element and its occurrence as contained in a MultiSet.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`boolean`	`add(E object)` Adds one copy of the specified object to the MultiSet.
`int`	`add(E object, int occurrences)` Adds a number of occurrences of the specified object to the MultiSet.
`boolean`	`containsAll(java.util.Collection<?> coll)` Returns `true` if the MultiSet contains at least one occurrence for each element contained in the given collection.
`java.util.Set<MultiSet.Entry<E>>`	`entrySet()` Returns a `Set` of all entries contained in the MultiSet.
`boolean`	`equals(java.lang.Object obj)` Compares this MultiSet to another object.
`int`	`getCount(java.lang.Object object)` Returns the number of occurrences of the given object currently in the MultiSet.
`int`	`hashCode()` Gets a hash code for the MultiSet compatible with the definition of equals.
`java.util.Iterator<E>`	`iterator()` Returns an `Iterator` over the entire set of members, including copies due to cardinality.
`boolean`	`remove(java.lang.Object object)` Removes one occurrence of the given object from the MultiSet.
`int`	`remove(java.lang.Object object, int occurrences)` Removes a number of occurrences of the specified object from the MultiSet.
`boolean`	`removeAll(java.util.Collection<?> coll)` Remove all occurrences of all elements from this MultiSet represented in the given collection.
`boolean`	`retainAll(java.util.Collection<?> coll)` Remove any elements of this MultiSet that are not contained in the given collection.
`int`	`setCount(E object, int count)` Sets the number of occurrences of the specified object in the MultiSet to the given count.
`int`	`size()` Returns the total number of items in the MultiSet.
`java.util.Set<E>`	`uniqueSet()` Returns a `Set` of unique elements in the MultiSet.

Methods inherited from interface java.util.Collection
addAll, clear, contains, isEmpty, parallelStream, removeIf, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable
forEach

- Method Detail
  - getCount
```
int getCount(java.lang.Object object)
```
    Returns the number of occurrences of the given object currently in the MultiSet. If the object does not exist in the multiset, return 0.
    
    Parameters:
    
    object - the object to search for
    
    Returns:
    
    the number of occurrences of the object, zero if not found
  - setCount
```
int setCount(E object,
             int count)
```
    Sets the number of occurrences of the specified object in the MultiSet to the given count.
    If the provided count is zero, the object will be removed from the uniqueSet().
    
    Parameters:
    
    object - the object to update
    
    count - the number of occurrences of the object
    
    Returns:
    
    the number of occurrences of the object before this operation, zero if the object was not contained in the multiset
    
    Throws:
    
    java.lang.IllegalArgumentException - if count is negative
  - add
```
boolean add(E object)
```
    Adds one copy of the specified object to the MultiSet.
    If the object is already in the uniqueSet() then increment its count as reported by getCount(Object). Otherwise add it to the uniqueSet() and report its count as 1.
    
    Specified by:
    
    add in interface java.util.Collection<E>
    
    Parameters:
    
    object - the object to add
    
    Returns:
    
    true always, as the size of the MultiSet is increased in any case
  - add
```
int add(E object,
        int occurrences)
```
    Adds a number of occurrences of the specified object to the MultiSet.
    If the object is already in the uniqueSet() then increment its count as reported by getCount(Object). Otherwise add it to the uniqueSet() and report its count as occurrences.
    
    Parameters:
    
    object - the object to add
    
    occurrences - the number of occurrences to add, may be zero, in which case no change is made to the multiset
    
    Returns:
    
    the number of occurrences of the object in the multiset before this operation; possibly zero
    
    Throws:
    
    java.lang.IllegalArgumentException - if occurrences is negative
  - remove
```
boolean remove(java.lang.Object object)
```
    Removes one occurrence of the given object from the MultiSet.
    If the number of occurrences after this operations is reduced to zero, the object will be removed from the uniqueSet().
    
    Specified by:
    
    remove in interface java.util.Collection<E>
    
    Parameters:
    
    object - the object to remove
    
    Returns:
    
    true if this call changed the collection
  - remove
```
int remove(java.lang.Object object,
           int occurrences)
```
    Removes a number of occurrences of the specified object from the MultiSet.
    If the number of occurrences to remove is greater than the actual number of occurrences in the multiset, the object will be removed from the multiset.
    
    Parameters:
    
    object - the object to remove
    
    occurrences - the number of occurrences to remove, may be zero, in which case no change is made to the multiset
    
    Returns:
    
    the number of occurrences of the object in the multiset before the operation; possibly zero
    
    Throws:
    
    java.lang.IllegalArgumentException - if occurrences is negative
  - uniqueSet
```
java.util.Set<E> uniqueSet()
```
    Returns a Set of unique elements in the MultiSet.
    Uniqueness constraints are the same as those in Set.
    The returned set is backed by this multiset, so any change to either is immediately reflected in the other. Only removal operations are supported, in which case all occurrences of the element are removed from the backing multiset.
    
    Returns:
    
    the Set of unique MultiSet elements
  - entrySet
```
java.util.Set<MultiSet.Entry<E>> entrySet()
```
    Returns a Set of all entries contained in the MultiSet.
    The returned set is backed by this multiset, so any change to either is immediately reflected in the other.
    
    Returns:
    
    the Set of MultiSet entries
  - iterator
```
java.util.Iterator<E> iterator()
```
    Returns an Iterator over the entire set of members, including copies due to cardinality. This iterator is fail-fast and will not tolerate concurrent modifications.
    
    Specified by:
    
    iterator in interface java.util.Collection<E>
    
    Specified by:
    
    iterator in interface java.lang.Iterable<E>
    
    Returns:
    
    iterator over all elements in the MultiSet
  - size
```
int size()
```
    Returns the total number of items in the MultiSet.
    
    Specified by:
    
    size in interface java.util.Collection<E>
    
    Returns:
    
    the total size of the multiset
  - containsAll
```
boolean containsAll(java.util.Collection<?> coll)
```
    Returns true if the MultiSet contains at least one occurrence for each element contained in the given collection.
    
    Specified by:
    
    containsAll in interface java.util.Collection<E>
    
    Parameters:
    
    coll - the collection to check against
    
    Returns:
    
    true if the MultiSet contains all the collection
  - removeAll
```
boolean removeAll(java.util.Collection<?> coll)
```
    Remove all occurrences of all elements from this MultiSet represented in the given collection.
    
    Specified by:
    
    removeAll in interface java.util.Collection<E>
    
    Parameters:
    
    coll - the collection of elements to remove
    
    Returns:
    
    true if this call changed the multiset
  - retainAll
```
boolean retainAll(java.util.Collection<?> coll)
```
    Remove any elements of this MultiSet that are not contained in the given collection.
    
    Specified by:
    
    retainAll in interface java.util.Collection<E>
    
    Parameters:
    
    coll - the collection of elements to retain
    
    Returns:
    
    true if this call changed the multiset
  - equals
```
boolean equals(java.lang.Object obj)
```
    Compares this MultiSet to another object.
    This MultiSet equals another object if it is also a MultiSet that contains the same number of occurrences of the same elements.
    
    Specified by:
    
    equals in interface java.util.Collection<E>
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    obj - the object to compare to
    
    Returns:
    
    true if equal
  - hashCode
```
int hashCode()
```
    Gets a hash code for the MultiSet compatible with the definition of equals. The hash code is defined as the sum total of a hash code for each element. The per element hash code is defined as (e==null ? 0 : e.hashCode()) ^ noOccurances).
    
    Specified by:
    
    hashCode in interface java.util.Collection<E>
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    the hash code of the MultiSet

Interface MultiSet<E>

Nested Class Summary

Method Summary

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Method Detail

getCount

setCount

add

add

remove

remove

uniqueSet

entrySet

iterator

size

containsAll

removeAll

retainAll

equals

hashCode