ery.jvrpn.1.0.1.source-code.ButtonRemoteListener Maven / Gradle / Ivy
/***************************************************************************
* Use this class to store ButtonUpdate in a vector and get them when you
* want. It is most useful if you don't want to worry about your code
* running in a multi-threaded environment and about vrpn possibly deliver-
* ing device updates at arbitrary times.
*
* The Listener can be configured to buffer and return either all
* updates or only the last (the most recent) update. By default, it
* keeps only the last update.
*
* It is not intended that Listeners be shared among objects. Each
* entity in a program that is interested in hearing about updates
* from some vrpn Button device (and which wishes to use this Listener
* mechanism) should create its own listener (even if multiple entities
* wish to hear from the same device).
***************************************************************************/
package vrpn;
import java.util.Vector;
public class ButtonRemoteListener implements ButtonRemote.ButtonChangeListener
{
public static final int ALL_UPDATES = 0;
public static final int LAST_UPDATE = 1;
public ButtonRemoteListener(ButtonRemote button)
{
buttonUpdates = new Vector();
bufferMode = LAST_UPDATE;
button.addButtonChangeListener(this);
}
/**
* Sets the buffering mode of the Listener to record and return only
* the most recent (the last, the latest) ButtonUpdate.
*/
public synchronized void setModeLastButtonUpdate()
{
bufferMode = LAST_UPDATE;
if (!buttonUpdates.isEmpty())
{
Object temp = buttonUpdates.lastElement();
buttonUpdates.removeAllElements();
buttonUpdates.addElement(temp);
}
}
/**
* Sets the buffering mode of the Listener to record and return all
* ButtonUpdates, beginning at the time this mode is first enabled.
*/
public synchronized void setModeAllButtonUpdates()
{
if( bufferMode == LAST_UPDATE )
{
buttonUpdates.removeAllElements( );
}
bufferMode = ALL_UPDATES;
}
/**
* @return ButtonRemoteListener.ALL_UPDATES if the Listener is recording and
* returning all ButtonUpdates; ButtonRemoteListener.LAST_UPDATE if only the
* latest ButtonUpdate.
*/
public synchronized int getModeButtonUpdate()
{
return bufferMode;
}
/**
* This method retreives the buffered ButtonUpdates from the Listener.
* If the buffering mode is LAST_UPDATE, the last update received will
* be returned (note that, in this mode, successive calls to getButtonUpdate()
* may return the same ButtonUpdate if no new updates were received in the
* interim). If the buffering mode is ALL_UPDATES, all updates
* received since the last call to getButtonUpdate() (or since ALL_UPDATES
* mode was enabled) will be returned.
* @return A Vector containing the buffered ButtonUpdates. The number of
* ButtonUpdates returned will depend on the buffering mode. If there are
* no ButtonUpdates buffered, an empty Vector will be returned.
* @see #setModeLastButtonUpdate
* @see #setModeAllButtonUpdates
*/
public synchronized Vector getButtonUpdate()
{
Vector v = new Vector( );
if( buttonUpdates.isEmpty() )
{
return v;
}
if( bufferMode == LAST_UPDATE )
{
v.addElement( buttonUpdates.lastElement() );
}
else if( bufferMode == ALL_UPDATES )
{
for( int i = 0; i < buttonUpdates.size(); i++ )
{
v.addElement( buttonUpdates.elementAt(i) );
}
buttonUpdates.removeAllElements();
}
return v;
} // end method getButtonUpdate()
/**
* @return The last (most recent, latest) ButtonUpdate received. This function
* returns null if no updates have been received. Note that
* successive calls to getLastButtonUpdate() may return the same ButtonUpdate
* if no updates were received in the interim.
*/
public synchronized ButtonRemote.ButtonUpdate getLastButtonUpdate()
{
if( buttonUpdates.isEmpty( ) )
return null;
return (ButtonRemote.ButtonUpdate) buttonUpdates.lastElement();
}
/**
* This is the handler that the ButtonRemote instance will call to deliver updates.
* This method is not intended to be called by user code.
*/
public synchronized void buttonUpdate (ButtonRemote.ButtonUpdate u, ButtonRemote button)
{
if( bufferMode == LAST_UPDATE )
{
buttonUpdates.removeAllElements();
}
buttonUpdates.addElement(u);
}
protected Vector buttonUpdates;
protected int bufferMode;
} // end class ButtonRemoteListener