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package org.netbeans.modules.javahelp;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.logging.Level;
import javax.help.HelpSet;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeListener;
import org.netbeans.api.javahelp.Help;
import org.openide.util.ChangeSupport;
import org.openide.util.Lookup;
import org.openide.util.LookupEvent;
import org.openide.util.LookupListener;
/** An implementation of the JavaHelp system (a little more concrete).
* @author Jesse Glick
*/
public abstract class AbstractHelp extends Help implements HelpConstants {
/** constructor for subclasses
*/
protected AbstractHelp() {}
/** the results of the search for helpsets
*/
private Lookup.Result<HelpSet> helpsets = null;
/** Get all available help sets.
* Pay attention to {@link #helpSetsChanged} to see
* when this set will change.
* @return a collection of HelpSet
*/
protected final Collection<? extends HelpSet> getHelpSets() {
if (helpsets == null) {
Installer.log.fine("searching for instances of HelpSet...");
helpsets = Lookup.getDefault().lookupResult(HelpSet.class);
helpsets.addLookupListener(new LookupListener() {
public void resultChanged(LookupEvent ev) {
helpSetsChanged();
}
});
fireChangeEvent(); // since someone may be listening to whether they are ready
}
Collection<? extends HelpSet> c = helpsets.allInstances();
if (Installer.log.isLoggable(Level.FINE)) {
List<String> l = new ArrayList<String>(Math.min(1, c.size()));
for (HelpSet hs: c) {
l.add(hs.getTitle());
}
Installer.log.fine("listing helpsets: " + l);
}
return c;
}
/** Are the help sets ready?
* @return true if they have been loaded
*/
protected final boolean helpSetsReady() {
return helpsets != null;
}
/** Whether a given help set is supposed to be merged
* into the master set.
* @param hs the help set
* @return true if so
*/
protected final boolean shouldMerge(HelpSet hs) {
Boolean b = (Boolean)hs.getKeyData(HELPSET_MERGE_CONTEXT, HELPSET_MERGE_ATTR);
return (b == null) || b.booleanValue();
}
/** Called when the set of available help sets changes.
* Fires a change event to listeners; subclasses may
* do extra cleanup.
*/
protected void helpSetsChanged() {
Installer.log.fine("helpSetsChanged");
fireChangeEvent();
}
public final void addChangeListener(ChangeListener l) {
cs.addChangeListener(l);
}
public final void removeChangeListener(ChangeListener l) {
cs.removeChangeListener(l);
}
private final ChangeSupport cs = new ChangeSupport(this);
/** Fire a change event to all listeners.
*/
private final void fireChangeEvent() {
if (!SwingUtilities.isEventDispatchThread()) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
fireChangeEvent();
}
});
return;
}
Installer.log.fine("Help.stateChanged");
cs.fireChange();
}
}
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