AbstractMapBag (Apache Commons Collections 3.2.2 API)

java.lang.Object
- org.apache.commons.collections.bag.AbstractMapBag

All Implemented Interfaces:

Iterable, Collection, Bag

Direct Known Subclasses:

HashBag, TreeBag
```
public abstract class AbstractMapBag
extends Object
implements Bag
```
Abstract implementation of the Bag interface to simplify the creation of subclass implementations.
Subclasses specify a Map implementation to use as the internal storage. The map will be used to map bag elements to a number; the number represents the number of occurrences of that element in the bag.

Since:

Commons Collections 3.0 (previously DefaultMapBag v2.0)

Version:

$Revision: 972404 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Chuck Burdick, Michael A. Smith, Stephen Colebourne, Janek Bogucki, Steve Clark

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected static class AbstractMapBag.MutableInteger
Mutable integer class for storing the data.

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`AbstractMapBag.MutableInteger` Mutable integer class for storing the data.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`AbstractMapBag()` Constructor needed for subclass serialisation.
`protected`	`AbstractMapBag(Map map)` Constructor that assigns the specified Map as the backing store.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`add(Object object)` Adds a new element to the bag, incrementing its count in the underlying map.
`boolean`	`add(Object object, int nCopies)` Adds a new element to the bag, incrementing its count in the map.
`boolean`	`addAll(Collection coll)` Invokes `add(Object)` for each element in the given collection.
`void`	`clear()` Clears the bag by clearing the underlying map.
`boolean`	`contains(Object object)` Determines if the bag contains the given element by checking if the underlying map contains the element as a key.
`boolean`	`containsAll(Collection coll)` Determines if the bag contains the given elements.
`protected void`	`doReadObject(Map map, ObjectInputStream in)` Read the map in using a custom routine.
`protected void`	`doWriteObject(ObjectOutputStream out)` Write the map out using a custom routine.
`boolean`	`equals(Object object)` Compares this Bag to another.
`int`	`getCount(Object object)` Returns the number of occurrence of the given element in this bag by looking up its count in the underlying map.
`protected Map`	`getMap()` Utility method for implementations to access the map that backs this bag.
`int`	`hashCode()` Gets a hash code for the Bag compatible with the definition of equals.
`boolean`	`isEmpty()` Returns true if the underlying map is empty.
`Iterator`	`iterator()` Gets an iterator over the bag elements.
`boolean`	`remove(Object object)` Removes all copies of the specified object from the bag.
`boolean`	`remove(Object object, int nCopies)` Removes a specified number of copies of an object from the bag.
`boolean`	`removeAll(Collection coll)` Removes objects from the bag according to their count in the specified collection.
`boolean`	`retainAll(Collection coll)` Remove any members of the bag that are not in the given bag, respecting cardinality.
`int`	`size()` Returns the number of elements in this bag.
`Object[]`	`toArray()` Returns an array of all of this bag's elements.
`Object[]`	`toArray(Object[] array)` Returns an array of all of this bag's elements.
`String`	`toString()` Implement a toString() method suitable for debugging.
`Set`	`uniqueSet()` Returns an unmodifiable view of the underlying map's key set.

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

- Constructor Detail
  - AbstractMapBag
```
protected AbstractMapBag()
```
    Constructor needed for subclass serialisation.
  - AbstractMapBag
```
protected AbstractMapBag(Map map)
```
    Constructor that assigns the specified Map as the backing store. The map must be empty and non-null.
    
    Parameters:
    map - the map to assign
- Method Detail
  - getMap
```
protected Map getMap()
```
    Utility method for implementations to access the map that backs this bag. Not intended for interactive use outside of subclasses.
    
    Returns:
    the map being used by the Bag
  - size
```
public int size()
```
    Returns the number of elements in this bag.
    
    Specified by:
    
    size in interface Collection
    
    Specified by:
    
    size in interface Bag
    
    Returns:
    current size of the bag
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if the underlying map is empty.
    
    Specified by:
    
    isEmpty in interface Collection
    
    Returns:
    true if bag is empty
  - getCount
```
public int getCount(Object object)
```
    Returns the number of occurrence of the given element in this bag by looking up its count in the underlying map.
    
    Specified by:
    
    getCount in interface Bag
    
    Parameters:
    object - the object to search for
    
    Returns:
    the number of occurrences of the object, zero if not found
  - contains
```
public boolean contains(Object object)
```
    Determines if the bag contains the given element by checking if the underlying map contains the element as a key.
    
    Specified by:
    
    contains in interface Collection
    
    Parameters:
    object - the object to search for
    
    Returns:
    true if the bag contains the given element
  - containsAll
```
public boolean containsAll(Collection coll)
```
    Determines if the bag contains the given elements.
    
    Specified by:
    
    containsAll in interface Collection
    
    Specified by:
    
    containsAll in interface Bag
    
    Parameters:
    coll - the collection to check against
    
    Returns:
    true if the Bag contains all the collection
  - iterator
```
public Iterator iterator()
```
    Gets an iterator over the bag elements. Elements present in the Bag more than once will be returned repeatedly.
    
    Specified by:
    
    iterator in interface Iterable
    
    Specified by:
    
    iterator in interface Collection
    
    Specified by:
    
    iterator in interface Bag
    
    Returns:
    the iterator
  - add
```
public boolean add(Object object)
```
    Adds a new element to the bag, incrementing its count in the underlying map.
    
    Specified by:
    
    add in interface Collection
    
    Specified by:
    
    add in interface Bag
    
    Parameters:
    object - the object to add
    
    Returns:
    true if the object was not already in the uniqueSet
  - add
```
public boolean add(Object object,
          int nCopies)
```
    Adds a new element to the bag, incrementing its count in the map.
    
    Specified by:
    
    add in interface Bag
    
    Parameters:
    object - the object to search for
    nCopies - the number of copies to add
    
    Returns:
    true if the object was not already in the uniqueSet
  - addAll
```
public boolean addAll(Collection coll)
```
    Invokes add(Object) for each element in the given collection.
    
    Specified by:
    
    addAll in interface Collection
    
    Parameters:
    coll - the collection to add
    
    Returns:
    true if this call changed the bag
  - clear
```
public void clear()
```
    Clears the bag by clearing the underlying map.
    
    Specified by:
    
    clear in interface Collection
  - remove
```
public boolean remove(Object object)
```
    Removes all copies of the specified object from the bag.
    
    Specified by:
    
    remove in interface Collection
    
    Specified by:
    
    remove in interface Bag
    
    Parameters:
    object - the object to remove
    
    Returns:
    true if the bag changed
  - remove
```
public boolean remove(Object object,
             int nCopies)
```
    Removes a specified number of copies of an object from the bag.
    
    Specified by:
    
    remove in interface Bag
    
    Parameters:
    object - the object to remove
    nCopies - the number of copies to remove
    
    Returns:
    true if the bag changed
  - removeAll
```
public boolean removeAll(Collection coll)
```
    Removes objects from the bag according to their count in the specified collection.
    
    Specified by:
    
    removeAll in interface Collection
    
    Specified by:
    
    removeAll in interface Bag
    
    Parameters:
    coll - the collection to use
    
    Returns:
    true if the bag changed
  - retainAll
```
public boolean retainAll(Collection coll)
```
    Remove any members of the bag that are not in the given bag, respecting cardinality.
    
    Specified by:
    
    retainAll in interface Collection
    
    Specified by:
    
    retainAll in interface Bag
    
    Parameters:
    coll - the collection to retain
    
    Returns:
    true if this call changed the collection
  - toArray
```
public Object[] toArray()
```
    Returns an array of all of this bag's elements.
    
    Specified by:
    
    toArray in interface Collection
    
    Returns:
    an array of all of this bag's elements
  - toArray
```
public Object[] toArray(Object[] array)
```
    Returns an array of all of this bag's elements.
    
    Specified by:
    
    toArray in interface Collection
    
    Parameters:
    array - the array to populate
    
    Returns:
    an array of all of this bag's elements
  - uniqueSet
```
public Set uniqueSet()
```
    Returns an unmodifiable view of the underlying map's key set.
    
    Specified by:
    
    uniqueSet in interface Bag
    
    Returns:
    the set of unique elements in this bag
  - doWriteObject
```
protected void doWriteObject(ObjectOutputStream out)
                      throws IOException
```
    Write the map out using a custom routine.
    
    Parameters:
    out - the output stream
    
    Throws:
    
    IOException
  - doReadObject
```
protected void doReadObject(Map map,
                ObjectInputStream in)
                     throws IOException,
                            ClassNotFoundException
```
    Read the map in using a custom routine.
    
    Parameters:
    map - the map to use
    in - the input stream
    
    Throws:
    
    IOException
    
    ClassNotFoundException
  - equals
```
public boolean equals(Object object)
```
    Compares this Bag to another. This Bag equals another Bag if it contains the same number of occurrences of the same elements.
    
    Specified by:
    
    equals in interface Collection
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    object - the Bag to compare to
    
    Returns:
    true if equal
  - hashCode
```
public int hashCode()
```
    Gets a hash code for the Bag 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). This hash code is compatible with the Set interface.
    
    Specified by:
    
    hashCode in interface Collection
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    the hash code of the Bag
  - toString
```
public String toString()
```
    Implement a toString() method suitable for debugging.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    a debugging toString

Class AbstractMapBag

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

AbstractMapBag

AbstractMapBag

Method Detail

getMap

size

isEmpty

getCount

contains

containsAll

iterator

add

add

addAll

clear

remove

remove

removeAll

retainAll

toArray

toArray

uniqueSet

doWriteObject

doReadObject

equals

hashCode

toString