AbstractMultiSet

java.lang.Object
- java.util.AbstractCollection<E>
- - org.apache.commons.collections4.multiset.AbstractMultiSet<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, MultiSet<E>

Direct Known Subclasses:

AbstractMapMultiSet
```
public abstract class AbstractMultiSet<E>
extends AbstractCollection<E>
implements MultiSet<E>
```
Abstract implementation of the MultiSet interface to simplify the creation of subclass implementations.

Since:

4.1

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
`protected static class`	`AbstractMultiSet.AbstractEntry<E>` Inner class AbstractEntry.
`protected static class`	`AbstractMultiSet.EntrySet<E>` Inner class EntrySet.
`protected static class`	`AbstractMultiSet.UniqueSet<E>` Inner class UniqueSet.

Nested classes/interfaces inherited from interface org.apache.commons.collections4.MultiSet
MultiSet.Entry<E>

Constructor Summary

Constructors

Modifier	Constructor and Description
`protected`	`AbstractMultiSet()` Constructor needed for subclass serialisation.

Method Summary

All Methods

Instance Methods

Abstract Methods

Concrete 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.
`void`	`clear()` Clears the multiset removing all elements from the entrySet.
`boolean`	`contains(Object object)` Determines if the multiset contains the given element.
`protected Set<MultiSet.Entry<E>>`	`createEntrySet()` Create a new view for the set of entries in this multiset.
`protected abstract Iterator<MultiSet.Entry<E>>`	`createEntrySetIterator()` Creates an entry set iterator.
`protected Set<E>`	`createUniqueSet()` Create a new view for the set of unique elements in this multiset.
`protected Iterator<E>`	`createUniqueSetIterator()` Creates a unique set iterator.
`protected void`	`doReadObject(ObjectInputStream in)` Read the multiset in using a custom routine.
`protected void`	`doWriteObject(ObjectOutputStream out)` Write the multiset out using a custom routine.
`Set<MultiSet.Entry<E>>`	`entrySet()` Returns an unmodifiable view of the entries of this multiset.
`boolean`	`equals(Object object)` Compares this MultiSet to another object.
`int`	`getCount(Object object)` Returns the number of occurrence of the given element in this multiset by iterating over its entrySet.
`int`	`hashCode()` Gets a hash code for the MultiSet compatible with the definition of equals.
`Iterator<E>`	`iterator()` Gets an iterator over the multiset elements.
`boolean`	`remove(Object object)` Removes one occurrence of the given object from the MultiSet.
`int`	`remove(Object object, int occurrences)` Removes a number of occurrences of the specified object from the MultiSet.
`boolean`	`removeAll(Collection<?> coll)` Remove all occurrences of all elements from this MultiSet represented 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 number of elements in this multiset.
`String`	`toString()` Implement a toString() method suitable for debugging.
`protected abstract int`	`uniqueElements()` Returns the number of unique elements in this multiset.
`Set<E>`	`uniqueSet()` Returns a view of the unique elements of this multiset.

Methods inherited from class java.util.AbstractCollection
addAll, containsAll, isEmpty, retainAll, toArray, toArray

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.commons.collections4.MultiSet
containsAll, retainAll

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

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - AbstractMultiSet
```
protected AbstractMultiSet()
```
    Constructor needed for subclass serialisation.
- Method Detail
  - size
```
public int size()
```
    Returns the number of elements in this multiset.
    
    Specified by:
    
    size in interface Collection<E>
    
    Specified by:
    
    size in interface MultiSet<E>
    
    Specified by:
    
    size in class AbstractCollection<E>
    
    Returns:
    
    current size of the multiset
  - getCount
```
public int getCount(Object object)
```
    Returns the number of occurrence of the given element in this multiset by iterating over its entrySet.
    
    Specified by:
    
    getCount in interface MultiSet<E>
    
    Parameters:
    
    object - the object to search for
    
    Returns:
    
    the number of occurrences of the object, zero if not found
  - setCount
```
public int setCount(E object,
                    int count)
```
    Description copied from interface: MultiSet
    
    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 MultiSet.uniqueSet().
    
    Specified by:
    
    setCount in interface MultiSet<E>
    
    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
  - contains
```
public boolean contains(Object object)
```
    Determines if the multiset contains the given element.
    
    Specified by:
    
    contains in interface Collection<E>
    
    Overrides:
    
    contains in class AbstractCollection<E>
    
    Parameters:
    
    object - the object to search for
    
    Returns:
    
    true if the multiset contains the given element
  - iterator
```
public Iterator<E> iterator()
```
    Gets an iterator over the multiset elements. Elements present in the MultiSet more than once will be returned repeatedly.
    
    Specified by:
    
    iterator in interface Iterable<E>
    
    Specified by:
    
    iterator in interface Collection<E>
    
    Specified by:
    
    iterator in interface MultiSet<E>
    
    Specified by:
    
    iterator in class AbstractCollection<E>
    
    Returns:
    
    the iterator
  - add
```
public boolean add(E object)
```
    Description copied from interface: MultiSet
    
    Adds one copy of the specified object to the MultiSet.
    If the object is already in the MultiSet.uniqueSet() then increment its count as reported by MultiSet.getCount(Object). Otherwise add it to the MultiSet.uniqueSet() and report its count as 1.
    
    Specified by:
    
    add in interface Collection<E>
    
    Specified by:
    
    add in interface MultiSet<E>
    
    Overrides:
    
    add in class AbstractCollection<E>
    
    Parameters:
    
    object - the object to add
    
    Returns:
    
    true always, as the size of the MultiSet is increased in any case
  - add
```
public int add(E object,
               int occurrences)
```
    Description copied from interface: MultiSet
    
    Adds a number of occurrences of the specified object to the MultiSet.
    If the object is already in the MultiSet.uniqueSet() then increment its count as reported by MultiSet.getCount(Object). Otherwise add it to the MultiSet.uniqueSet() and report its count as occurrences.
    
    Specified by:
    
    add in interface MultiSet<E>
    
    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
  - clear
```
public void clear()
```
    Clears the multiset removing all elements from the entrySet.
  - remove
```
public boolean remove(Object object)
```
    Description copied from interface: MultiSet
    
    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 MultiSet.uniqueSet().
    
    Specified by:
    
    remove in interface Collection<E>
    
    Specified by:
    
    remove in interface MultiSet<E>
    
    Overrides:
    
    remove in class AbstractCollection<E>
    
    Parameters:
    
    object - the object to remove
    
    Returns:
    
    true if this call changed the collection
  - remove
```
public int remove(Object object,
                  int occurrences)
```
    Description copied from interface: MultiSet
    
    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.
    
    Specified by:
    
    remove in interface MultiSet<E>
    
    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
  - removeAll
```
public boolean removeAll(Collection<?> coll)
```
    Description copied from interface: MultiSet
    
    Remove all occurrences of all elements from this MultiSet represented in the given collection.
    
    Specified by:
    
    removeAll in interface Collection<E>
    
    Specified by:
    
    removeAll in interface MultiSet<E>
    
    Overrides:
    
    removeAll in class AbstractCollection<E>
    
    Parameters:
    
    coll - the collection of elements to remove
    
    Returns:
    
    true if this call changed the multiset
  - uniqueSet
```
public Set<E> uniqueSet()
```
    Returns a view of the unique elements of this multiset.
    
    Specified by:
    
    uniqueSet in interface MultiSet<E>
    
    Returns:
    
    the set of unique elements in this multiset
  - createUniqueSet
```
protected Set<E> createUniqueSet()
```
    Create a new view for the set of unique elements in this multiset.
    
    Returns:
    
    a view of the set of unique elements
  - createUniqueSetIterator
```
protected Iterator<E> createUniqueSetIterator()
```
    Creates a unique set iterator. Subclasses can override this to return iterators with different properties.
    
    Returns:
    
    the uniqueSet iterator
  - entrySet
```
public Set<MultiSet.Entry<E>> entrySet()
```
    Returns an unmodifiable view of the entries of this multiset.
    
    Specified by:
    
    entrySet in interface MultiSet<E>
    
    Returns:
    
    the set of entries in this multiset
  - createEntrySet
```
protected Set<MultiSet.Entry<E>> createEntrySet()
```
    Create a new view for the set of entries in this multiset.
    
    Returns:
    
    a view of the set of entries
  - uniqueElements
```
protected abstract int uniqueElements()
```
    Returns the number of unique elements in this multiset.
    
    Returns:
    
    the number of unique elements
  - createEntrySetIterator
```
protected abstract Iterator<MultiSet.Entry<E>> createEntrySetIterator()
```
    Creates an entry set iterator. Subclasses can override this to return iterators with different properties.
    
    Returns:
    
    the entrySet iterator
  - doWriteObject
```
protected void doWriteObject(ObjectOutputStream out)
                      throws IOException
```
    Write the multiset out using a custom routine.
    
    Parameters:
    
    out - the output stream
    
    Throws:
    
    IOException - any of the usual I/O related exceptions
  - doReadObject
```
protected void doReadObject(ObjectInputStream in)
                     throws IOException,
                            ClassNotFoundException
```
    Read the multiset in using a custom routine.
    
    Parameters:
    
    in - the input stream
    
    Throws:
    
    IOException - any of the usual I/O related exceptions
    
    ClassNotFoundException - if the stream contains an object which class can not be loaded
    
    ClassCastException - if the stream does not contain the correct objects
  - equals
```
public boolean equals(Object object)
```
    Description copied from interface: MultiSet
    
    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 Collection<E>
    
    Specified by:
    
    equals in interface MultiSet<E>
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    object - the object to compare to
    
    Returns:
    
    true if equal
  - hashCode
```
public int hashCode()
```
    Description copied from interface: MultiSet
    
    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 Collection<E>
    
    Specified by:
    
    hashCode in interface MultiSet<E>
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    the hash code of the MultiSet
  - toString
```
public String toString()
```
    Implement a toString() method suitable for debugging.
    
    Overrides:
    
    toString in class AbstractCollection<E>
    
    Returns:
    
    a debugging toString

Class AbstractMultiSet<E>

Nested Class Summary

Nested Classes

Nested classes/interfaces inherited from interface org.apache.commons.collections4.MultiSet

Constructor Summary

Constructors

Method Summary

Methods inherited from class java.util.AbstractCollection

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.commons.collections4.MultiSet

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

AbstractMultiSet

Method Detail

size

getCount

setCount

contains

iterator

add

add

clear

remove

remove

removeAll

uniqueSet

createUniqueSet

createUniqueSetIterator

entrySet

createEntrySet

uniqueElements

createEntrySetIterator

doWriteObject

doReadObject

equals

hashCode

toString