java::util::HashSet Class Reference

This class implements the Set interface, backed by a hash table (actually a HashMap instance). More...

#include <java_util_HashSet.h>

Inheritance diagram for java::util::HashSet:

[legend]Collaboration diagram for java::util::HashSet:

[legend]List of all members.

Public Types
enum	{   xmogDefaultFlags = xmog_base::GLOBAL, xmogMajorVersion = 3, xmogMinorVersion = 2, xmogPatchVersion = 9,   xmogBuildNumber = 2047 }
typedef ::xmog_java_array_template< ::java::util::HashSet >	array1D
typedef ::xmog_java_array_template< ::xmog_java_array_template< ::java::util::HashSet > >	array2D
Public Member Functions
virtual bool	add (const ::java::lang::Object &o,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Adds the specified element to this set if it is not already present.
virtual void	clear (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Removes all of the elements from this set.
virtual ::java::lang::Object	clone (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns a shallow copy of this HashSet instance: the elements themselves are not cloned.
virtual bool	contains (const ::java::lang::Object &o,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns true if this set contains the specified element.
virtual bool	equals (const ::java::lang::Object &obj,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	The method representing the Java method java.lang.Object.equals().
virtual jint	hashCode (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	The method representing the Java method java.lang.Object.hashCode().
	HashSet (jint initialCapacity, jfloat loadFactor, bool dummy,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Constructs a new, empty linked hash set.
	HashSet (jint initialCapacity, jfloat loadFactor,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Constructs a new, empty set; the backing HashMap instance has the specified initial capacity and the specified load factor.
	HashSet (::xmog_dummy _use_java_ctor,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Constructs a new, empty set; the backing HashMap instance has default initial capacity (16) and load factor (0.75).
	HashSet (const ::java::util::Collection &c,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Constructs a new set containing the elements in the specified collection.
	HashSet (jint initialCapacity,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Constructs a new, empty set; the backing HashMap instance has the specified initial capacity and default load factor, which is 0.75.
virtual bool	isEmpty (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns true if this set contains no elements.
virtual ::java::util::Iterator	iterator (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns an iterator over the elements in this set.
virtual bool	remove (const ::java::lang::Object &o,::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Removes the specified element from this set if it is present.
virtual jint	size (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	Returns the number of elements in this set (its cardinality).
virtual ::java::lang::String	toString (::xmog_localenv *p_xenv=NULL, xmog_flags f_xflags=xmogDefaultFlags)
	The method representing the Java method java.lang.Object.toString().

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Detailed Description

This class implements the Set interface, backed by a hash table (actually a HashMap instance).

It makes no guarantees as to the iteration order of the set; in particular, it does not guarantee that the order will remain constant over time. This class permits the null element.

This class offers constant time performance for the basic operations (add, remove, contains and size), assuming the hash function disperses the elements properly among the buckets. Iterating over this set requires time proportional to the sum of the HashSet instance's size (the number of elements) plus the "capacity" of the backing HashMap instance (the number of buckets). Thus, it's very important not to set the initial capacity too high (or the load factor too low) if iteration performance is important.

Note that this implementation is not synchronized. If multiple threads access a set concurrently, and at least one of the threads modifies the set, it must be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the set. If no such object exists, the set should be "wrapped" using the Collections.synchronizedSet method. This is best done at creation time, to prevent accidental unsynchronized access to the HashSet instance:

                 Set s = Collections.synchronizedSet(new HashSet(...));

The iterators returned by this class's iterator method are fail-fast: if the set is modified at any time after the iterator is created, in any way except through the iterator's own remove method, the Iterator throws a ConcurrentModificationException. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.

Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.

This class is a member of the Java Collections Framework.

Author:

Josh Bloch

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Constructor & Destructor Documentation

java::util::HashSet::HashSet (  jint  initialCapacity, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Constructs a new, empty set; the backing HashMap instance has the specified initial capacity and default load factor, which is 0.75. Parameters: initialCapacity  the initial capacity of the hash table. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL.

java::util::HashSet::HashSet (  const ::java::util::Collection &  c, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Constructs a new set containing the elements in the specified collection. The HashMap is created with default load factor (0.75) and an initial capacity sufficient to contain the elements in the specified collection. Parameters: c  the collection whose elements are to be placed into this set. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL.

java::util::HashSet::HashSet (  ::xmog_dummy  _use_java_ctor, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Constructs a new, empty set; the backing HashMap instance has default initial capacity (16) and load factor (0.75). Parameters: _use_java_ctor  indicates that you want to delegate to a Java constructor whose natural proxy conflicts with a C++ requirement. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL.

java::util::HashSet::HashSet (  jint  initialCapacity, jfloat  loadFactor, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Constructs a new, empty set; the backing HashMap instance has the specified initial capacity and the specified load factor. Parameters: initialCapacity  the initial capacity of the hash map. loadFactor  the load factor of the hash map. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL.

java::util::HashSet::HashSet (  jint  initialCapacity, jfloat  loadFactor, bool  dummy, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Constructs a new, empty linked hash set. (This package private constructor is only used by LinkedHashSet.) The backing HashMap instance is a LinkedHashMap with the specified initial capacity and the specified load factor. Parameters: initialCapacity  the initial capacity of the hash map. loadFactor  the load factor of the hash map. dummy  ignored (distinguishes this constructor from other int, float constructor.) p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL.

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Member Function Documentation

virtual bool java::util::HashSet::add (  const ::java::lang::Object &  o, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Adds the specified element to this set if it is not already present. Parameters: o  element to be added to this set. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: true if the set did not already contain the specified element. Reimplemented from java::util::AbstractSet.

virtual void java::util::HashSet::clear (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Removes all of the elements from this set. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: Reimplemented from java::util::AbstractSet.

virtual ::java::lang::Object java::util::HashSet::clone (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Returns a shallow copy of this HashSet instance: the elements themselves are not cloned. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: a shallow copy of this set.

virtual bool java::util::HashSet::contains (  const ::java::lang::Object &  o, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Returns true if this set contains the specified element. Parameters: o  element whose presence in this set is to be tested. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: true if this set contains the specified element. Reimplemented from java::util::AbstractSet.

virtual bool java::util::HashSet::equals (  const ::java::lang::Object &  obj, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

The method representing the Java method java.lang.Object.equals(). Parameters: obj  p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Reimplemented from java::util::AbstractSet.

virtual jint java::util::HashSet::hashCode (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

The method representing the Java method java.lang.Object.hashCode(). Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Reimplemented from java::util::AbstractSet.

virtual bool java::util::HashSet::isEmpty (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Returns true if this set contains no elements. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: true if this set contains no elements. Reimplemented from java::util::AbstractSet.

virtual ::java::util::Iterator java::util::HashSet::iterator (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

Returns an iterator over the elements in this set. The elements are returned in no particular order. Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: an Iterator over the elements in this set. Reimplemented from java::util::AbstractSet.

virtual bool java::util::HashSet::remove (  const ::java::lang::Object &  o, ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Removes the specified element from this set if it is present. Parameters: o  object to be removed from this set, if present. p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: true if the set contained the specified element. Reimplemented from java::util::AbstractSet.

virtual jint java::util::HashSet::size (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )  [virtual]

Returns the number of elements in this set (its cardinality). Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Returns: the number of elements in this set (its cardinality). Reimplemented from java::util::AbstractSet.

virtual ::java::lang::String java::util::HashSet::toString (  ::xmog_localenv *  p_xenv = NULL, xmog_flags  f_xflags = xmogDefaultFlags )

The method representing the Java method java.lang.Object.toString(). Parameters: p_xenv  the local call environment. The default value is NULL. f_xflags  the flags that allow control over the reference type and other internal matters. The default value is xmog_base::GLOBAL. Reimplemented from java::util::AbstractSet.

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The documentation for this class was generated from the following file:

• java_util_HashSet.h

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