drools-eclipse/org.drools.eclipse/src/main/java/org/drools/eclipse/editors/rete/model/GraphicalVertex.java
public void removeConnection(Connection conn) {
        if ( conn == null ) {
            throw new IllegalArgumentException();
        }
        if ( conn.getSource() == this ) {
            sourceConnections.remove( conn );
            firePropertyChange( SOURCE_CONNECTIONS_PROP,
                                null,
                                conn );
        } else if ( conn.getTarget() == this ) {
            targetConnections.remove( conn );
            firePropertyChange( TARGET_CONNECTIONS_PROP,
                                null,
                                conn );
        }
    }
public void removeConnection(Connection conn) {
        if ( conn == null ) {
            throw new IllegalArgumentException();
        }
        if ( conn.getSource() == this ) {
            sourceConnections.remove( conn );
            firePropertyChange( SOURCE_CONNECTIONS_PROP,
                                null,
                                conn );
        } else if ( conn.getTarget() == this ) {
            targetConnections.remove( conn );
            firePropertyChange( TARGET_CONNECTIONS_PROP,
                                null,
                                conn );
        }
    }
Remove an incoming or outgoing connection from this vertex.

@param conn a non-null connection instance
@throws IllegalArgumentException if the parameter is null