// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.data.osm;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.logging.Logger;
import javax.swing.SwingUtilities;
import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.Preferences.PreferenceChangeEvent;
import org.openstreetmap.josm.data.Preferences.PreferenceChangedListener;
/**
* ChangesetCache is global in-memory cache for changesets downloaded from
* an OSM API server. The unique instance is available as singleton, see
* {@see #getInstance()}.
*
* Clients interested in cache updates can register for {@see ChangesetCacheEvent}s
* using {@see #addChangesetCacheListener(ChangesetCacheListener)}. They can use
* {@see #removeChangesetCacheListener(ChangesetCacheListener)} to unregister as
* cache event listener.
*
* The cache itself listens to {@see java.util.prefs.PreferenceChangeEvent}s. It
* clears itself if the OSM API URL is changed in the preferences.
*
* {@see ChangesetCacheEvent}s are delivered on the EDT.
*
*/
public class ChangesetCache implements PreferenceChangedListener{
@SuppressWarnings("unused")
static private final Logger logger = Logger.getLogger(ChangesetCache.class.getName());
/** the unique instance */
static private final ChangesetCache instance = new ChangesetCache();
/**
* Replies the unique instance of the cache
*
* @return the unique instance of the cache
*/
public static ChangesetCache getInstance() {
return instance;
}
/** the cached changesets */
private final Map<Integer, Changeset> cache = new HashMap<Integer, Changeset>();
private final CopyOnWriteArrayList<ChangesetCacheListener> listeners =
new CopyOnWriteArrayList<ChangesetCacheListener>();
private ChangesetCache() {
Main.pref.addPreferenceChangeListener(this);
}
public void addChangesetCacheListener(ChangesetCacheListener listener) {
listeners.addIfAbsent(listener);
}
public void removeChangesetCacheListener(ChangesetCacheListener listener) {
listeners.remove(listener);
}
protected void fireChangesetCacheEvent(final ChangesetCacheEvent e) {
Runnable r = new Runnable() {
public void run() {
for(ChangesetCacheListener l: listeners) {
l.changesetCacheUpdated(e);
}
}
};
if (SwingUtilities.isEventDispatchThread()) {
r.run();
} else {
SwingUtilities.invokeLater(r);
}
}
protected void update(Changeset cs, DefaultChangesetCacheEvent e) {
if (cs == null) return;
if (cs.isNew()) return;
Changeset inCache = cache.get(cs.getId());
if (inCache != null) {
inCache.mergeFrom(cs);
e.rememberUpdatedChangeset(inCache);
} else {
e.rememberAddedChangeset(cs);
cache.put(cs.getId(), cs);
}
}
public void update(Changeset cs) {
DefaultChangesetCacheEvent e = new DefaultChangesetCacheEvent(this);
update(cs, e);
fireChangesetCacheEvent(e);
}
public void update(Collection<Changeset> changesets) {
if (changesets == null || changesets.isEmpty()) return;
DefaultChangesetCacheEvent e = new DefaultChangesetCacheEvent(this);
for (Changeset cs: changesets) {
update(cs, e);
}
fireChangesetCacheEvent(e);
}
public boolean contains(int id) {
if (id <=0) return false;
return cache.get(id) != null;
}
public boolean contains(Changeset cs) {
if (cs == null) return false;
if (cs.isNew()) return false;
return contains(cs.getId());
}
public Changeset get(int id) {
return cache.get(id);
}
public Set<Changeset> getChangesets() {
return new HashSet<Changeset>(cache.values());
}
protected void remove(int id, DefaultChangesetCacheEvent e) {
if (id <= 0) return;
Changeset cs = cache.get(id);
if (cs == null) return;
cache.remove(id);
e.rememberRemovedChangeset(cs);
}
public void remove(int id) {
DefaultChangesetCacheEvent e = new DefaultChangesetCacheEvent(this);
remove(id, e);
if (! e.isEmpty()) {
fireChangesetCacheEvent(e);
}
}
public void remove(Changeset cs) {
if (cs == null) return;
if (cs.isNew()) return;
remove(cs.getId());
}
/**
* Removes the changesets in <code>changesets</code> from the cache. A
* {@see ChangesetCacheEvent} is fired.
*
* @param changesets the changesets to remove. Ignored if null.
*/
public void remove(Collection<Changeset> changesets) {
if (changesets == null) return;
DefaultChangesetCacheEvent evt = new DefaultChangesetCacheEvent(this);
for (Changeset cs : changesets) {
if (cs == null || cs.isNew()) {
continue;
}
remove(cs.getId(), evt);
}
if (! evt.isEmpty()) {
fireChangesetCacheEvent(evt);
}
}
public int size() {
return cache.size();
}
public void clear() {
DefaultChangesetCacheEvent e = new DefaultChangesetCacheEvent(this);
for (Changeset cs: cache.values()) {
e.rememberRemovedChangeset(cs);
}
cache.clear();
fireChangesetCacheEvent(e);
}
public List<Changeset> getOpenChangesets() {
List<Changeset> ret = new ArrayList<Changeset>();
for (Changeset cs: cache.values()) {
if (cs.isOpen()) {
ret.add(cs);
}
}
return ret;
}
/* ------------------------------------------------------------------------- */
/* interface PreferenceChangedListener */
/* ------------------------------------------------------------------------- */
public void preferenceChanged(PreferenceChangeEvent e) {
if (e.getKey() == null || ! e.getKey().equals("osm-server.url"))
return;
// clear the cache when the API url changes
if (e.getOldValue() == null || e.getNewValue() == null || !e.getOldValue().equals(e.getNewValue())) {
clear();
}
}
}