org.apache.commons.collections4.bag

Class TreeBag<E>

java.lang.Object

org.apache.commons.collections4.bag.AbstractMapBag<E>

org.apache.commons.collections4.bag.TreeBag<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, Bag<E>, SortedBag<E>

public class TreeBag<E>
extends AbstractMapBag<E>
implements SortedBag<E>, java.io.Serializable

Implements SortedBag, using a TreeMap to provide the data storage. This is the standard implementation of a sorted bag.

Order will be maintained among the bag members and can be viewed through the iterator.

A Bag stores each object in the collection together with a count of occurrences. Extra methods on the interface allow multiple copies of an object to be added or removed at once. It is important to read the interface javadoc carefully as several methods violate the Collection interface specification.

Since:

3.0 (previously in main package v2.0)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
TreeBag() Constructs an empty TreeBag.
TreeBag(java.util.Collection<? extends E> coll) Constructs a TreeBag containing all the members of the specified collection.
TreeBag(java.util.Comparator<? super E> comparator) Constructs an empty bag that maintains order on its unique representative members according to the given Comparator.

Method Summary

Modifier and Type	Method and Description
boolean	add(E object) Adds a new element to the bag, incrementing its count in the underlying map.
java.util.Comparator<? super E>	comparator() Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.
E	first() Returns the first (lowest) member.
E	last() Returns the last (highest) member.

Methods inherited from class org.apache.commons.collections4.bag.AbstractMapBag

add, addAll, clear, contains, containsAll, equals, getCount, hashCode, isEmpty, iterator, remove, remove, removeAll, retainAll, size, toArray, toArray, toString, uniqueSet

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

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

add, containsAll, getCount, iterator, remove, remove, removeAll, retainAll, size, uniqueSet

Methods inherited from interface java.util.Collection

addAll, clear, contains, equals, hashCode, isEmpty, parallelStream, removeIf, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

TreeBag

public TreeBag()

Constructs an empty TreeBag.

TreeBag

public TreeBag(java.util.Comparator<? super E> comparator)

Constructs an empty bag that maintains order on its unique representative members according to the given Comparator.

Parameters:

comparator - the comparator to use

TreeBag

public TreeBag(java.util.Collection<? extends E> coll)

Constructs a TreeBag containing all the members of the specified collection.

Parameters:

coll - the collection to copy into the bag

Method Detail

add

public boolean add(E object)

Adds a new element to the bag, incrementing its count in the underlying map.

Specified by:

add in interface java.util.Collection<E>

Specified by:

add in interface Bag<E>

Overrides:

add in class AbstractMapBag<E>

Parameters:

object - the object to add

Returns:

true if the object was not already in the uniqueSet

Throws:

java.lang.IllegalArgumentException - if the object to be added does not implement Comparable and the TreeBag is using natural ordering

java.lang.NullPointerException - if the specified key is null and this bag uses natural ordering, or its comparator does not permit null keys

first

public E first()

Description copied from interface: SortedBag

Returns the first (lowest) member.

Specified by:

first in interface SortedBag<E>

Returns:

the first element in the sorted bag

last

public E last()

Description copied from interface: SortedBag

Returns the last (highest) member.

Specified by:

last in interface SortedBag<E>

Returns:

the last element in the sorted bag

comparator

public java.util.Comparator<? super E> comparator()

Description copied from interface: SortedBag

Returns the comparator associated with this sorted set, or null if it uses its elements' natural ordering.

Specified by:

comparator in interface SortedBag<E>

Returns:

the comparator in use, or null if natural ordering