Package org.openstreetmap.josm.data.osm

Class ChangesetCache

java.lang.Object

org.openstreetmap.josm.data.osm.ChangesetCache

All Implemented Interfaces:

PreferenceChangedListener

public final class ChangesetCache
extends java.lang.Object
implements PreferenceChangedListener

ChangesetCache is global in-memory cache for changesets downloaded from an OSM API server. The unique instance is available as singleton, see getInstance(). Clients interested in cache updates can register for ChangesetCacheEvents using addChangesetCacheListener(ChangesetCacheListener). They can use removeChangesetCacheListener(ChangesetCacheListener) to unregister as cache event listener. The cache itself listens to PreferenceChangeEvents. It clears itself if the OSM API URL is changed in the preferences.

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.Map<java.lang.Integer,Changeset>	cache	the cached changesets
private static ChangesetCache	INSTANCE	the unique instance
(package private) java.util.concurrent.CopyOnWriteArrayList<ChangesetCacheListener>	listeners

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ChangesetCache()	Constructs a new ChangesetCache.

Method Summary

Modifier and Type	Method	Description
void	addChangesetCacheListener(ChangesetCacheListener listener)	Add a changeset cache listener.
void	clear()	Clears the cache.
boolean	contains(int id)	Determines if the cache contains an entry for given changeset identifier.
boolean	contains(Changeset cs)	Determines if the cache contains an entry for given changeset.
private void	fireChangesetCacheEvent(ChangesetCacheEvent e)
Changeset	get(int id)	Returns the entry for given changeset identifier.
java.util.Set<Changeset>	getChangesets()	Returns the set of changesets contained in the cache.
static ChangesetCache	getInstance()	Replies the unique instance of the cache
java.util.List<Changeset>	getOpenChangesets()	Replies the list of open changesets.
java.util.List<Changeset>	getOpenChangesetsForCurrentUser()	If the current user is known, the open changesets for the current user are returned.
void	preferenceChanged(PreferenceChangeEvent e)	Triggered when a preference entry value changes.
void	refreshChangesetsFromServer()	Refreshes the changesets from the server.
void	remove(int id)	Remove the entry for the given changeset identifier.
private void	remove(int id, DefaultChangesetCacheEvent e)
void	remove(java.util.Collection<Changeset> changesets)	Removes the changesets in changesets from the cache.
void	remove(Changeset cs)	Remove the entry for the given changeset.
void	removeChangesetCacheListener(ChangesetCacheListener listener)	Remove a changeset cache listener.
int	size()	Returns the number of changesets contained in the cache.
void	update(java.util.Collection<Changeset> changesets)	Update a collection of changesets.
void	update(Changeset cs)	Update a single changeset.
private void	update(Changeset cs, DefaultChangesetCacheEvent e)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

private static final ChangesetCache INSTANCE

the unique instance

cache

private final java.util.Map<java.lang.Integer,Changeset> cache

the cached changesets

listeners

final java.util.concurrent.CopyOnWriteArrayList<ChangesetCacheListener> listeners

Constructor Detail

ChangesetCache

private ChangesetCache()

Constructs a new ChangesetCache.

Method Detail

getInstance

public static ChangesetCache getInstance()

Replies the unique instance of the cache

Returns:

the unique instance of the cache

addChangesetCacheListener

public void addChangesetCacheListener(ChangesetCacheListener listener)

Add a changeset cache listener.

Parameters:

listener - changeset cache listener to add

removeChangesetCacheListener

public void removeChangesetCacheListener(ChangesetCacheListener listener)

Remove a changeset cache listener.

Parameters:

listener - changeset cache listener to remove

fireChangesetCacheEvent

private void fireChangesetCacheEvent(ChangesetCacheEvent e)

update

private void update(Changeset cs,
                    DefaultChangesetCacheEvent e)

update

public void update(Changeset cs)

Update a single changeset.

Parameters:

cs - changeset to update

update

public void update(java.util.Collection<Changeset> changesets)

Update a collection of changesets.

Parameters:

changesets - changesets to update

contains

public boolean contains(int id)

Determines if the cache contains an entry for given changeset identifier.

Parameters:

id - changeset id

Returns:

true if the cache contains an entry for id

contains

public boolean contains(Changeset cs)

Determines if the cache contains an entry for given changeset.

Parameters:

cs - changeset

Returns:

true if the cache contains an entry for cs

get

public Changeset get(int id)

Returns the entry for given changeset identifier.

Parameters:

id - changeset id

Returns:

the entry for given changeset identifier, or null

getChangesets

public java.util.Set<Changeset> getChangesets()

Returns the set of changesets contained in the cache.

Returns:

the set of changesets contained in the cache

remove

private void remove(int id,
                    DefaultChangesetCacheEvent e)

remove

public void remove(int id)

Remove the entry for the given changeset identifier. A ChangesetCacheEvent is fired.

Parameters:

id - changeset id

remove

public void remove(Changeset cs)

Remove the entry for the given changeset. A ChangesetCacheEvent is fired.

Parameters:

cs - changeset

remove

public void remove(java.util.Collection<Changeset> changesets)

Removes the changesets in changesets from the cache. A ChangesetCacheEvent is fired.

Parameters:

changesets - the changesets to remove. Ignored if null.

size

public int size()

Returns the number of changesets contained in the cache.

Returns:

the number of changesets contained in the cache

clear

public void clear()

Clears the cache.

getOpenChangesets

public java.util.List<Changeset> getOpenChangesets()

Replies the list of open changesets.

Returns:

The list of open changesets

getOpenChangesetsForCurrentUser

public java.util.List<Changeset> getOpenChangesetsForCurrentUser()

If the current user is known, the open changesets for the current user are returned. Otherwise, the unfiltered open changesets are returned.

Returns:

a list of changesets

refreshChangesetsFromServer

public void refreshChangesetsFromServer()
                                 throws OsmTransferException

Refreshes the changesets from the server.

The server automatically closes changesets after a timeout. We don't get notified of this fact when it happens. This method requests a fresh list from the server and updates the local list. Calling this method reduces (but does not eliminate) the probability of attempting an upload to an already closed changeset.

Throws:

OsmTransferException - on server error

preferenceChanged

public void preferenceChanged(PreferenceChangeEvent e)

Description copied from interface: PreferenceChangedListener

Triggered when a preference entry value changes.

Specified by:

preferenceChanged in interface PreferenceChangedListener

Parameters:

e - the preference change event