Package com.tangosol.util

Class SubSet<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<E>

com.tangosol.util.SubSet<E>

All Implemented Interfaces:

Cloneable, Iterable<E>, Collection<E>, Set<E>

public class SubSet<E>
extends AbstractSet<E>
implements Cloneable

Implements a set which is based on another set, which is assumed to be immutable. The SubSet is assumed to be a subset of the underlying set, and optimizes for both remove and retain operations. If the underlying (original) set is sorted, the SubSet's iterator() will iterate items in the ascending order.

This implementation is not thread-safe.

Author:

cp 2003.01.29

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	SubSet.SubSetIterator	Iterator for the contents of a subset in the "removed" mode.

Field Summary

Fields

Modifier and Type	Field	Description
protected static final Object[]	EMPTY_ARRAY	An empty immutable array.
protected boolean	m_fRetained	Toggles between whether the modifications are removed or retained.
protected Set<E>	m_setMod	The removed or retained items.
protected Set<E>	m_setOrig	The underlying set (assumed immutable).

Constructor Summary

Constructors

Constructor	Description
SubSet(Set<? extends E> set)	Construct this set based on an existing set.

Method Summary

Modifier and Type	Method	Description
boolean	add(E e)
boolean	addAll(Collection<? extends E> col)
void	clear()
Object	clone()	Clone the subset.
boolean	contains(Object o)
boolean	containsAll(Collection<?> col)
protected Set<E>	ensureRemoved()	Get a mutable set of items that are removed in the subset.
protected Set<E>	ensureRetained()	Get a mutable set of items that are retained in the subset.
Set<? extends E>	getOriginal()	Determine what items were in the original set.
Set<E>	getRemoved()	Determine what items were removed from the subset.
Set<E>	getRetained()	Determine what items were added to the subset.
protected Set<E>	instantiateModificationSet(int cSize)	Instantiate a new modification set containing either removed or retained items.
boolean	isEmpty()
boolean	isModified()	Determine if the set has been modified.
boolean	isTrackingRetained()	Determine if the SubSet is tracking retained items versus removed items.
Iterator	iterator()
boolean	remove(Object o)
boolean	removeAll(Collection<?> col)
void	reset()	Discard the changes to the set ("rollback").
protected void	resetState(Set setOrig, Set setMod, boolean fRetained)	Reset the state of the subset according to the specified parameters.
void	resolve()	Apply the changes to the underlying set ("commit").
boolean	retainAll(Collection<?> col)
protected void	retainAllInternal(Collection colOuter, Collection colMatch, Set setExclude)	Instantiate a new retained set with all elements in the specified collection that also exist in the provided colMatch collection and are not excluded.
int	size()
Object[]	toArray()
Object[]	toArray(Object[] ao)

Methods inherited from class java.util.AbstractSet

equals, hashCode

Methods inherited from class java.util.AbstractCollection

toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

spliterator

Field Details

EMPTY_ARRAY

protected static final Object[] EMPTY_ARRAY

An empty immutable array.

m_setOrig

protected Set<E> m_setOrig

The underlying set (assumed immutable).

m_setMod

protected Set<E> m_setMod

The removed or retained items.

m_fRetained

protected boolean m_fRetained

Toggles between whether the modifications are removed or retained.

Constructor Details

SubSet

public SubSet(Set<? extends E> set)

Construct this set based on an existing set.

Parameters:

set - the set to base this subset on

Method Details

getOriginal

public Set<? extends E> getOriginal()

Determine what items were in the original set.

Returns:

the set used to construct this SubSet

isModified

public boolean isModified()

Determine if the set has been modified.

Returns:

true if any items have been removed

isTrackingRetained

public boolean isTrackingRetained()

Determine if the SubSet is tracking retained items versus removed items.

Returns:

true if the SubSet is tracking just the retained items, false if the SubSet is tracking just the removed items

getRetained

public Set<E> getRetained()

Determine what items were added to the subset. Do not modify the returned set.

Returns:

a set of retained items

getRemoved

public Set<E> getRemoved()

Determine what items were removed from the subset.

Returns:

an immutable set of removed items

instantiateModificationSet

protected Set<E> instantiateModificationSet(int cSize)

Instantiate a new modification set containing either removed or retained items.

Parameters:

cSize - an initial size of the modification set

ensureRetained

protected Set<E> ensureRetained()

Get a mutable set of items that are retained in the subset.

Returns:

a mutable set of retained items

ensureRemoved

protected Set<E> ensureRemoved()

Get a mutable set of items that are removed in the subset.

Returns:

a mutable set of removed items

resolve

public void resolve()

Apply the changes to the underlying set ("commit").

reset

public void reset()

Discard the changes to the set ("rollback").

resetState

protected void resetState(Set setOrig,
 Set setMod,
 boolean fRetained)

Reset the state of the subset according to the specified parameters.

Parameters:

setOrig - the new original set

setMod - the set of removed or retained entries, depending on the fRetained flag

fRetained - if true setMod contains the retained entries; otherwise the removed entries

iterator

public Iterator iterator()

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Set<E>

Specified by:

iterator in class AbstractCollection<E>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

Specified by:

isEmpty in interface Set<E>

Overrides:

isEmpty in class AbstractCollection<E>

size

public int size()

Specified by:

size in interface Collection<E>

Specified by:

size in interface Set<E>

Specified by:

size in class AbstractCollection<E>

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface Set<E>

Overrides:

contains in class AbstractCollection<E>

containsAll

public boolean containsAll(Collection<?> col)

Specified by:

containsAll in interface Collection<E>

Specified by:

containsAll in interface Set<E>

Overrides:

containsAll in class AbstractCollection<E>

add

public boolean add(E e)

Specified by:

add in interface Collection<E>

Specified by:

add in interface Set<E>

Overrides:

add in class AbstractCollection<E>

addAll

public boolean addAll(Collection<? extends E> col)

Specified by:

addAll in interface Collection<E>

Specified by:

addAll in interface Set<E>

Overrides:

addAll in class AbstractCollection<E>

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface Set<E>

Overrides:

remove in class AbstractCollection<E>

removeAll

public boolean removeAll(Collection<?> col)

Specified by:

removeAll in interface Collection<E>

Specified by:

removeAll in interface Set<E>

Overrides:

removeAll in class AbstractSet<E>

retainAll

public boolean retainAll(Collection<?> col)

Specified by:

retainAll in interface Collection<E>

Specified by:

retainAll in interface Set<E>

Overrides:

retainAll in class AbstractCollection<E>

clear

public void clear()

Specified by:

clear in interface Collection<E>

Specified by:

clear in interface Set<E>

Overrides:

clear in class AbstractCollection<E>

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface Set<E>

Overrides:

toArray in class AbstractCollection<E>

toArray

public Object[] toArray(Object[] ao)

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface Set<E>

Overrides:

toArray in class AbstractCollection<E>

clone

public Object clone()

Clone the subset.

Overrides:

clone in class Object

Returns:

a clone of this subset

retainAllInternal

protected void retainAllInternal(Collection colOuter,
 Collection colMatch,
 Set setExclude)

Instantiate a new retained set with all elements in the specified collection that also exist in the provided colMatch collection and are not excluded.

Parameters:

colOuter - collection to iterate

colMatch - each element in colOuter should be present in this collection such that (colOuter ∩ colMatch)

setExclude - optional set of excluded elements