org.gjt.sp.jedit.EditBus Maven / Gradle / Ivy
/*
* EditBus.java - The EditBus
* :tabSize=8:indentSize=8:noTabs=false:
* :folding=explicit:collapseFolds=1:
*
* Copyright (C) 1999 Slava Pestov
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package org.gjt.sp.jedit;
import java.util.*;
import org.gjt.sp.util.Log;
/**
* jEdit's global event notification mechanism.
*
* Plugins register with the EditBus to receive messages reflecting
* changes in the application's state, including changes in buffers,
* views and edit panes, changes in the set of properties maintained
* by the application, and the closing of the application.
*
* The EditBus maintains a list of objects that have requested to receive
* messages. When a message is sent using this class, all registered
* components receive it in turn. Classes for objects that subscribe to
* the EditBus must implement the {@link EBComponent} interface, which
* defines the single method {@link EBComponent#handleMessage(EBMessage)}.
*
* A plugin core class that extends the
* {@link EBPlugin} abstract class (and whose name ends with
* Plugin for identification purposes) will automatically be
* added to the EditBus during jEdit's startup routine. Any other
* class - for example, a dockable window that needs to receive
* notification of buffer changes - must perform its own registration by calling
* {@link #addToBus(EBComponent)} during its initialization.
* A convenient place to register in a class derived from JComponent
* would be in an implementation of the JComponent method
* addNotify().
*
* Message types sent by jEdit can be found in the
* {@link org.gjt.sp.jedit.msg} package.
*
* Plugins can also send their own messages - any object can send a message to
* the EditBus by calling the static method {@link #send(EBMessage)}.
* Most plugins, however, only concern themselves with receiving, not
* sending, messages.
*
* @see org.gjt.sp.jedit.EBComponent
* @see org.gjt.sp.jedit.EBMessage
*
* @author Slava Pestov
* @author John Gellene (API documentation)
* @version $Id: EditBus.java 12504 2008-04-22 23:12:43Z ezust $
*
* @since jEdit 2.2pre6
*/
public class EditBus
{
//{{{ addToBus() method
/**
* Adds a component to the bus. It will receive all messages sent
* on the bus.
*
* @param comp The component to add
*/
public static void addToBus(EBComponent comp)
{
synchronized(components)
{
components.add(comp);
copyComponents = null;
}
} //}}}
//{{{ removeFromBus() method
/**
* Removes a component from the bus.
* @param comp The component to remove
*/
public static void removeFromBus(EBComponent comp)
{
synchronized(components)
{
components.remove(comp);
copyComponents = null;
}
} //}}}
//{{{ getComponents() method
/**
* Returns an array of all components connected to the bus.
*/
public static EBComponent[] getComponents()
{
synchronized(components)
{
if (copyComponents == null)
{
copyComponents = (EBComponent[])components.toArray(
new EBComponent[components.size()]);
}
return copyComponents;
}
} //}}}
//{{{ send() method
/**
* Sends a message to all components on the bus in turn.
* @param message The message
*/
public static void send(EBMessage message)
{
Log.log(Log.DEBUG,EditBus.class,message.toString());
// To avoid any problems if components are added or removed
// while the message is being sent
EBComponent[] comps = getComponents();
for(int i = 0; i < comps.length; i++)
{
try
{
EBComponent comp = comps[i];
if(Debug.EB_TIMER)
{
long start = System.currentTimeMillis();
comp.handleMessage(message);
long time = (System.currentTimeMillis() - start);
if(time != 0)
{
Log.log(Log.DEBUG,EditBus.class,comp + ": " + time + " ms");
}
}
else
comps[i].handleMessage(message);
}
catch(Throwable t)
{
Log.log(Log.ERROR,EditBus.class,"Exception"
+ " while sending message on EditBus:");
Log.log(Log.ERROR,EditBus.class,t);
}
}
} //}}}
//{{{ Private members
private static ArrayList components = new ArrayList();
private static EBComponent[] copyComponents;
// can't create new instances
private EditBus() {}
//}}}
}