java.util
Class HashMap.KeySet

java.lang.Object
  java.util.AbstractCollection
      java.util.AbstractSet
          java.util.HashMap.KeySet

All Implemented Interfaces:

Collection, Set

Enclosing class:

HashMap

private class HashMap.KeySet

extends AbstractSet

Constructor Summary

private

HashMap.KeySet()

Method Summary

void	clear() Removes all of the elements from this set (optional operation).
boolean	contains(Object o) Returns true if this set contains the specified element.
Iterator	iterator() Returns an iterator over the elements in this set.
boolean	remove(Object o) Removes the specified element from this set if it is present (optional operation).
int	size() Returns the number of elements in this set (its cardinality).

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

add, addAll, containsAll, isEmpty, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

add, addAll, containsAll, isEmpty, retainAll, toArray, toArray

Constructor Detail

HashMap.KeySet

private HashMap.KeySet()

Method Detail

iterator

public Iterator iterator()

Description copied from interface: Set

Returns an iterator over the elements in this set. The elements are returned in no particular order (unless this set is an instance of some class that provides a guarantee).

Specified by:

iterator in interface Set

Specified by:

iterator in class AbstractCollection

Returns:

an iterator over the elements contained in this collection.

size

public int size()

Description copied from interface: Set

Returns the number of elements in this set (its cardinality). If this set contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Set

Specified by:

size in class AbstractCollection

Returns:

the number of elements in this collection.

contains

public boolean contains(Object o)

Description copied from interface: Set

Returns true if this set contains the specified element. More formally, returns true if and only if this set contains an element e such that (o==null ? e==null : o.equals(e)).

Specified by:

contains in interface Set

Overrides:

contains in class AbstractCollection

Parameters:

o - object to be checked for containment in this collection.

Returns:

true if this collection contains the specified element.

remove

public boolean remove(Object o)

Description copied from interface: Set

Removes the specified element from this set if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if the set contains such an element. Returns true if the set contained the specified element (or equivalently, if the set changed as a result of the call). (The set will not contain the specified element once the call returns.)

Specified by:

remove in interface Set

Overrides:

remove in class AbstractCollection

Parameters:

o - element to be removed from this collection, if present.

Returns:

true if the collection contained the specified element.

clear

public void clear()

Description copied from interface: Set

Removes all of the elements from this set (optional operation). This set will be empty after this call returns (unless it throws an exception).

Specified by:

clear in interface Set

Overrides:

clear in class AbstractCollection