GMChannelRouter.java

package org.herac.tuxguitar.gm;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class GMChannelRouter {
	
	public static final short MAX_CHANNELS = 16;
	public static final short PERCUSSION_CHANNEL = 9;
	
	private List midiChannels;
	
	public GMChannelRouter(){
		this.midiChannels = new ArrayList();
	}
	
	public void resetRoutes(){
		this.midiChannels.clear();
	}
	
	public void removeRoute(GMChannelRoute route){
		if( this.midiChannels.contains(route) ){
			this.midiChannels.remove(route);
		}
	}
	
	public GMChannelRoute getRoute(int channelId){
		Iterator channelIt = this.midiChannels.iterator();
		while( channelIt.hasNext() ){
			GMChannelRoute midiChannel = (GMChannelRoute) channelIt.next();
			if( midiChannel.getChannelId() == channelId ){
				return midiChannel;
			}
		}
		return null;
	}
	
	public void configureRoutes(GMChannelRoute route, boolean percussionChannel){
		List conflictingRoutes = null;
		
		if( this.midiChannels.contains(route) ){
			this.midiChannels.remove(route);
		}
		
		// Allways channel 9 for percussions
		if( percussionChannel ){
			route.setChannel1(PERCUSSION_CHANNEL);
			route.setChannel2(PERCUSSION_CHANNEL);
		}
		
		else {
			// Use custom routes 
			if( route.getChannel1() >= 0 ){
				if( route.getChannel2() < 0 ){
					route.setChannel2( route.getChannel1() );
				}
				conflictingRoutes = findConflictingRoutes(route);
			}
			
			// Add default routes
			else {
				List freeChannels = getFreeChannels();
				route.setChannel1(( freeChannels.size() > 0 ? ((Integer)freeChannels.get(0)).intValue() : GMChannelRoute.NULL_VALUE ) );
				route.setChannel2(( freeChannels.size() > 1 ? ((Integer)freeChannels.get(1)).intValue() : route.getChannel1() ) );
			}
		}
		
		this.midiChannels.add( route );
		
		// Reconfigure conflicting routes
		if( conflictingRoutes != null ){
			Iterator it = conflictingRoutes.iterator();
			while( it.hasNext() ){
				GMChannelRoute conflictingRoute = (GMChannelRoute)it.next();
				conflictingRoute.setChannel1(GMChannelRoute.NULL_VALUE);
				conflictingRoute.setChannel2(GMChannelRoute.NULL_VALUE);
				configureRoutes(conflictingRoute, false);
			}
		}
	}
	
	public List findConflictingRoutes(GMChannelRoute gmChannelRoute){
		List routes = new ArrayList();
		
		Iterator it = this.midiChannels.iterator();
		while( it.hasNext() ){
			GMChannelRoute route = (GMChannelRoute) it.next();
			if(!route.equals(gmChannelRoute) ){
				if( route.getChannel1() == gmChannelRoute.getChannel1() || 
					route.getChannel1() == gmChannelRoute.getChannel2() ||
					route.getChannel2() == gmChannelRoute.getChannel1() || 
					route.getChannel2() == gmChannelRoute.getChannel2() ){
					
					routes.add( route );
				}
			}
		}
		
		return routes;
	}
	
	public List getFreeChannels(){
		return getFreeChannels(null);
	}
	
	public List getFreeChannels(GMChannelRoute forRoute){
		List freeChannels = new ArrayList();
		
		for( int ch = 0 ; ch < MAX_CHANNELS ; ch ++ ){
			if( ch != PERCUSSION_CHANNEL ){
				boolean isFreeChannel = true;
				
				Iterator channelIt = this.midiChannels.iterator();
				while( channelIt.hasNext() ){
					GMChannelRoute route = (GMChannelRoute) channelIt.next();
					if( forRoute == null || !forRoute.equals( route ) ){
						if( route.getChannel1() == ch || route.getChannel2() == ch){
							isFreeChannel = false;
						}
					}
				}
				
				if( isFreeChannel ){
					freeChannels.add(new Integer(ch));
				}
			}
		}
		return freeChannels;
	}
}