openseadragon/src/eventhandler.js

(function($){

/**
 * @class
 */
$.EventHandler = function() {
    this.events = {};
};

$.EventHandler.prototype = {

    addHandler: function( id, handler ) {
        var events = this.events[ id ];
        if( !events ){
            this.events[ id ] = events = [];
        }
        events[ events.length ] = handler;
    },

    removeHandler: function( id, handler ) {
        //Start Thatcher - unneccessary indirection.  Also, because events were
        //               - not actually being removed, we need to add the code
        //               - to do the removal ourselves. TODO
        var events = this.events[ id ];
        if ( !events ){ 
            return; 
        }
        //End Thatcher
    },

    getHandler: function( id ) {
        var events = this.events[ id ]; 
        if ( !events || !events.length ){ 
            return null; 
        }
        events = events.length === 1 ? 
            [ events[ 0 ] ] : 
            Array.apply( null, events );
        return function( source, args ) {
            var i, 
                length = events.length;
            for ( i = 0; i < length; i++ ) {
                events[ i ]( source, args );
            }
        };
    },

    raiseEvent: function( eventName, eventArgs ) {
        var handler = this.getHandler( eventName );

        if ( handler ) {
            if ( !eventArgs ) {
                eventArgs = new Object();
            }

            handler( this, eventArgs );
        }
    }
};

}( OpenSeadragon ));