Source: sheet.js

/******************************************************************************
 * Sheet implementation
 * ***************************************************************************/
/**
 * Constructs a sheet
 * @param context {object} a context object
 * @class
 * @classdesc A Sheet is an operationnal configuration in an application. It 
 * contains many things: multiple sets of {@link ARCS.Invocation} 
 * performed at different times
 * and a set of {@link ARCS.Connection}. Sheets have two high level operations:
 * activation and deactivation. 
 */
ARCS.Sheet = function (context) {
    //var context = ctx;
    var preconnections = [], postconnections = [], cleanups = [], connections = [],
        invokePreconnections, invokePostconnections, invokeCleanups, connect, disconnect;
    invokePreconnections = function () {
        var i;
        for (i = 0; i < preconnections.length; i++) {
            preconnections[i].invoke();
        }
    };
    invokePostconnections = function () {
        var i;
        for (i = 0; i < postconnections.length; i++) {
            postconnections[i].invoke();
        }
    };
    invokeCleanups = function () {
        var i;
        for (i = 0; i < cleanups.length; i++) {
            cleanups[i].invoke();
        }
    };
    connect = function () {
        var i;
        for (i = 0; i < connections.length; i++) {
            connections[i].connect();
        }
    };
    disconnect = function () {
        var i;
        for (i = 0; i < connections.length; i++) {
            connections[i].disconnect();
        }
    };
    /**
     * Activates this sheet. Pre-connection invocations are peformed, then 
     * connections are established and post-connection invocations are finally 
     * performed.
     */
    this.activate = function () {
        invokePreconnections();
        connect();
        invokePostconnections();
    };
    /**
     * Deactivates this sheet. Connections are removed and then cleanup invocations
     * are performed.
     */
    this.deactivate = function () {
        disconnect();
        invokeCleanups();
    };
    /**
     * Imports a structure object describing the content of a sheet.
     * @param object {object} structured object describing sheet's content.
     */
    this.import = function (object) {
        var i = 0, castInvocation = ARCS.Invocation.cast, castConnection = ARCS.Connection.cast;
        for (i = 0; i < object.preconnections.length; i++) {
            preconnections.push(castInvocation(object.preconnections[i], context));
        }
        for (i = 0; i < object.postconnections.length; i++) {
            postconnections.push(castInvocation(object.postconnections[i], context));
        }
        for (i = 0; i < object.cleanups.length; i++) {
            cleanups.push(castInvocation(object.cleanups[i], context));
        }
        for (i = 0; i < object.connections.length; i++) {
            connections.push(castConnection(object.connections[i], context));
        }
    };
};