Business Rules/Logic

Applications created with Code On Time are equipped with a Universal Mobile/Desktop Client.  Application pages are rendered with a device-friendly user interface. Mobile smartphones and tablets display touch-enabled pages with lists and forms featuring a responsive design.

Multi-purpose pages behave as standalone units of a line-of-business application. This concept is known today as a Single Page Application. The concept is rapidly catching on with the mainstream development community. It has been an integral part of apps created with Code On Time for the past five years.

The power and flexibility of the Code On Time application framework is proven by the mere fact of its ability to work with two completely different client libraries. The same exact “Code”, “SQL”, “Email”, and “JavaScript” business rules and exactly the same pages work with both mobile and desktop client devices.

This year we will introduce amazing new forward-looking framework capabilities and a new product called http://cloudontime.com.

Mobile Client

Mobile Client is based on the leading mobile JavaScript framework jQuery Mobile 1.4, released in December of 2013. We have deliberated a lot while trying to pick the best mobile framework as the foundation of the mobile client and settled on JQM. Primary reasons are the extensive support of numerous mobile operating systems, huge following, and tight integration with jQuery.

The initial release of Mobile Client does not fully match its desktop counterpart when it comes to a few features such as advanced search, filtering, dynamic calculations of field values, and conditional visibility. The gap will be closed by the end of March 2014.

Presently, the mobile client supports a single default theme. We will offer a large number of alternative themes and provide customization instructions in the coming  months. Theme Roller for jQuery Mobile will be used to create the themes.

Our next goal for the Mobile Client is to provide Grid, Data Sheet, Hierarchy, Map, Calendar, and Chart views.

• Grid view will offer a “table” style responsive presentation of mobile lists. The number of visible columns will change depending on the screen size and device orientation.
• Data Sheet view is the production release of the 2nd generation data sheet that was first introduced in the desktop client. It will support inline editing of field values with a new touch-enabled scrolling mechanism.
• Hierarchy will be a feature of List, Grid, and Data Sheet views. The configuration of hierarchies is explained here.
• Map view will be based on Google Maps integrated with JQM.
• Calendar view is a touch-enabled custom implementation of a typical calendar. We will be borrowing presentation ideas from the leading mobile operating systems.
• Chart view will be an extension of current charting capabilities of the desktop client.

Release 8.0.3.0 features a Task Assistant displayed when users tap on the toolbar header text. Unlimited edition applications will also show History and Favorites tabs with lists of data cards representing master data records to facilitate business-related activities.

We are also working a on a few data input enhancements:

• “Basket” lookup style will complement “Check Box List” to enable multiple selection from a large number of options. This style of presentation will automatically activate if a list of “many-to-many” options is greater than a predefined number when rendered on mobile devices to improve presentation. “Basket” lookup will be available in Desktop Client after the initial introduction in the Mobile Client.
• Signature capturing will complement Blob adapters. Users will be able to draw a signature on touch-enabled screens. The signature will be stored as a high-resolution PNG image with an optional SVG version. This is a high-priority feature that will be first introduced in the Mobile Client.

Mobile Client on the Desktop

Universal Mobile/Desktop Client uses two different JavaScript libraries to render the user interface. The mobile client library is touch-enabled and works great with a mouse as well. You can see a mobile user interface demo in action on your desktop computer.

The current market trend in the desktop computing is the introduction of touch-enabled screens. Microsoft Windows 8 is touch-enabled. Most business users will end up having a touch-enabled computer in the near future.

The major difference between mobile and desktop presentation in a Code On Time app is the number of data views visible to a user at any moment:

• Desktop Client presents multi-level master-detail pages that allow a user to gain immediate access to data views on any level by scrolling the page up and down.
• Mobile Client displays only one data view of a multi-level master-detail page. User clicks on navigation buttons to access relevant data views from lower levels.  The drill-down approach is common in mobile operating systems. There is always a way to return back to the original top-level data views of a page.

Our development team is researching the possibility of creating multi-pane presentation with data views displayed each in its own pane on desktop devices. Additional panes will be revealed on the same screen when a user drills down to see related “detail” data.  The responsive design of the mobile client scales perfectly for a multi-pane presentation. Panes will be independently scrollable.

We will introduce the multi-pane capability in the mobile client in the near future.

Based on your input we will consider if this will be a good approach to follow when building touch-enabled line-of-business applications for both mobile and desktop devices. What do you think?

Offline Data Caching

Performance of line-of-business applications in HTML 5 web browsers can be greatly improved with client-side data caching. We will introduce ability to cache entire datasets exposed by data controller views on the client.

Data controller view will have a Tag property to control client-side caching. For example, tagging a data view as data-cache37 will cause the client library to look for data in the local storage of the browser before attempting to request data from the server. If the data is in the storage and it has been there less than 37 minutes, then the client library will not attempt to access the server and will use the cached data instead.

Tagging of a view for client-side caching will disable advanced search and will only leave Quick Find and Adaptive Filtering search options. Both operations will be performed via JavaScript entirely on the client.

Cached data will be scoped to the user identity and page. We will make sure that cascading lookups work correctly with cached data.

This unique capability will be available in both Mobile and Desktop client.

Offline Transactions

The current implementation of client library does not cache data changes in the browser. If a transactional data input is required, then we generally recommend to rely on your database server and follow transaction implementation strategies that include “Status” field, log tables, or staging tables. The described strategies will work perfectly well with mobile and desktop devices.

If a network connection is lost or unavailable, then the server-side transaction processing is not going to work.

Modern web browsers can notify a web page if a network connectivity is lost and when the client device is back online.

New tag data-offline will allow indicating that the page data views are supporting offline transactions. The tag will activate automatic caching of data requests to Update, Insert, and Delete data. Client library will store each AJAX request object in the local browser storage in the sequence the requests are initiated, without sending request to the server. The client library will execute “cached” requests locally to simulate the end result of Update, Insert, and Delete actions on the client. Developers will be able to implement custom JavaScript business rules in offline mode.

Two new actions “Commit” and “Rollback” will be supported. Actions will be visible in their scope only if there are pending “offline” changes. If a network connection is available, then “Commit” action will send all pending requests as a single array to the server for execution. The server will perform all request in the same sequence that was recorded on the client to allow the database server to persist changes. Simulated client-side data modifications will be discarded if all operations were successfully executed. “Rollback” will simply remove pending changes and restore client-side data to its initial state.

The primary objective of this feature is to allow implementing apps that can capture data without a mandatory interaction with the server. Signature capturing will also work in this mode.

Offline Mobile Client

HTML 5 standard defines a concept of an application manifest that helps a web browser to download all application resources such as HTML pages, JavaScript files, images, and CSS style sheets. Resources listed in a manifest are cached in the local browser storage. A manifest can also include resources that represent application data as static JavaScript structures.

We will implement a dynamic HTML 5 application manifest construction in Code On Time apps created with Unlimited edition. Only pages and data marked to work Offline will be included.

End users will be able to download the offline version of an app by simply entering the application web address followed by “offline” path. For example:

http://myapp.com/offline

The contents of the manifest will be downloaded when the app is accessed for the first time from an HTML 5 browser. This is basically a process of application installation.

The subsequent visits will follow this script:

• If a network connection is available, then a browser will ensure that the contents of the manifest and previously downloaded resources are up-to-date.
• If a network connection is not available, then verification of resources is skipped.
• The browser will proceed to display pages from the local storage.
• The client library will always check “local” resources before attempting to download data from the “network”.

Note that the offline app is not a separate application. It is is simply a capability of an app created with Code On Time to expose some of its functionality to offline users.

Offline apps will be provided with the Mobile Client user interface

Offline apps do not require distribution through the app stores of mobile operating systems.

Native Mobile Apps

Modern mobile development has a popular trend of building native apps with JavaScript and HTML, packaged to run in embedded web browsers of a mobile operating system. There are several popular tools that allow packaging a collection of HTML and JavaScript files as a native app.

The app generator will support production of pre-packaged files for at least one of such tools that will be announced in the second half of this year.

Native apps will have to be distributed through an app store of the chosen mobile operating platform.

Next Generation Desktop Client

Current implementation of Desktop Client works best on high resolution screens with the mouse and keyboard.

The next generation of the desktop client will be based on the mobile client and will feature a slide-down ribbon with context actions and menu options at the top of each page. Multi-pane pages on the desktop client will display containers arranged in multiple columns and rows, which will turn a page into a collection of scrollable tiles.

The new version of desktop client will ensure efficient desktop keyboard data entry in the forms and data sheet view.

We will likely offer additional presentation enhancements to various view styles that will benefit desktop users.

Mobile user interface themes will be adapted for improved desktop  presentation.

The details will become available in second half of 2014.

EASE (Enterprise Application Services Engine)

For the past few years we were building a collection of features under a moniker EASE (Enterprise Application Services Engine). Several key features have not been released to production as a part of Code On Time application framework. The key unreleased components are Workflow Register and Dynamic Access Control List. The initial implementations were complex and difficult to manage.

The latest iteration has been significantly streamlined.

DACL (Dynamic Access Control List) will not be a dedicated module in the generated apps as originally intended. Instead we have re-factored this into Workflow Register.

Workflow Register is based on a core set of 11 tables that will have to be hosted in the application database. There will be a set of built-in data controllers similar to Membership Manager that will allow managing configuration data in the tables. 

Workflow Register allows associating "Workflows" with Users and User Groups controlled by optional schedules.

"Workflow" is a combination of Rules.

Rules are matched to registered objects. Objects represent "business entities" of your app.

A rule may define:

1. SQL expression limiting access to data (Dynamic Access Control Rules)
2. Custom version of a data controller
3. Transformation of a data controller via Node Sets (Data Controller Virtualization)
4. Transformation of a data controller via XSLT (new feature)
5. Custom version of a page content (new feature)
6. Transformation of XHTML content (page) via XSLT (new feature - virtualization of pages)
7. Custom page URL for Search Engine Optimization

Application framework automatically "consults" rules of workflows matched to the current user when performing various life-cycle operations on controllers, pages, and data.

Installation of Workflow Register will include built-in business entities.  Built-in entities include:

1) blog
2) content
3) image
4) comment
5) support ticket
6) discussion

The described entities are there to support built-in Atom-based publishing module of the Content Management System of the application framework. This is a new feature of EASE.

Installation of Workflow Register in the database will allow building a dynamic website similar to http://codeontime.com with built-in blogging, community forum, and ticket-based support system. All these features will run alongside your own data controllers if enabled.

There will be built-in rules to control access to blogs, content, images, comments, support tickets, and discussions. Workflow Register will allow browsing and changing these rules. We expect the built-in rules to be a "live" example of Dynamic Access Rules that developers can use to model restrictions for their own data.

New EASE features will be integrated in the application framework in April/May of 2014.

Cloud On Time

The new product called http://cloudontime.com will go online in April of 2014. 

This product is an app created with Code On Time. The type of the project is Azure Factory.

Cloud On Time allows creating custom cloud apps on top of dedicated databases hosted in Windows Azure. The apps include Universal Mobile/Desktop Client and all EASE features.

Users will be able to create “cloud” tables using a browser on mobile and desktop devices. A built-in Designer works in the cloud and is modeled after Project Designer available in Code On Time app generator. Multi-user development teams will be able to cooperatively work on their projects.

Developers will customize projects with SQL, JavaScript, and Email business rules.

Monthly subscriptions with several levels and a free trial period will be available.

Subscribers can use a free standalone utility to download their entire cloud database from Cloud On Time to a local machine in a variety of formats.

The same utility will allow uploading an existing database to Cloud On Time.

The target  audience of the product:

• Business users who want to rapidly prototype a mobile or desktop line-of-business application without using developers.
• Professional development teams can quickly build complete apps hosted in a private database running in a shared cloud.
• Code On Time app generator users can prototype an app in a cloud and bring it locally for further development and deployment to their own platform of choice.

Data integrity is a primary concern of any database application. Data constraints must exist on the database and application server level, while client-side validation will make a web app more responsive and user-friendly.

For example, consider the following screenshot of the New Order Details form. End users can select any product and enter any price, quantity, and discount. The database engine will validate the constraints of the table Order Details and raise an exception when invalid data is submitted.

Let’s implement a code business rule that will perform more complex validation for Order Details controller.

Configuring Fields

Start the Project Designer. In the Project Explorer, switch to the Controllers tab and double-click on OrderDetails / Fields / ProductID* (Int32) –> Products node.

Change the following:

Press OK to save. Next, double-click on UnitPrice* (Decimal) field node.

Make the following changes:

Press OK to save.

Configuring Business Rule

Right-click on OrderDetails / Business Rules node, and press New Business Rule.

Assign the following values:

Press OK to save. On the toolbar, press Browse to generate the business rule file.

When complete, right-click on OrderDetails / Business Rules / Calculate|Insert|Update (Code / Execute) – r100 node, and press Edit Rule in Visual Studio.

Replace the code base with the following:

C#:

using System;
using System.Data;
using MyCompany.Data;

namespace MyCompany.Rules
{
    public partial class OrderDetailsBusinessRules : MyCompany.Data.BusinessRules
    {
        [Rule("r100")]
        public void r100Implementation(int? orderID,
            string orderCustomerID,
            string orderCustomerCompanyName,
            string orderEmployeeLastName,
            string orderShipViaCompanyName,
            FieldValue productID,
            string productProductName,
            string productCategoryCategoryName,
            string productSupplierCompanyName,
            FieldValue unitPrice,
            short? quantity,
            float? discount)
        {
            // 1. If the collected values are not valid then do not enforce the rule.
            //    The client library will instruct the user to correct the input.
            bool success = this.ValidateInput();
            string commandName = this.Arguments.CommandName;
            string triggerFieldName = this.Arguments.Trigger;

            // 2. Reset the base price for calculation of price limits 
            //    if the product selection has changed or if an existing
            //    data row has been selected for editing
            FieldValue oldProductID = (FieldValue)this.GetProperty("Session_ProductID"); 
            if (oldProductID == null || productID.Value.ToString() != oldProductID.Value.ToString())
            {
                decimal basePrice = Convert.ToDecimal(unitPrice.Value);
                if (!triggerFieldName.Equals("ProductID"))
                    basePrice = Convert.ToDecimal(unitPrice.OldValue);
                this.SetProperty("Session_UnitPrice", basePrice);
                this.SetProperty("Session_ProductID", productID);
                if (triggerFieldName.Equals("ProductID"))
                {
                    quantity = 1;
                    UpdateFieldValue("Quantity", quantity);
                    discount = 0;
                    UpdateFieldValue("Discount", discount);
                    Result.Focus("Quantity");
                }
            }
            // 3. Adjusting base price for an existing record
            decimal originalUnitPrice = (decimal)this.GetProperty("Session_UnitPrice");
            if (originalUnitPrice == null || originalUnitPrice == 0)
            {
                originalUnitPrice = Convert.ToDecimal(unitPrice.OldValue);
                this.SetProperty("Session_UnitPrice", originalUnitPrice);
            }
            // 4. validate Unit Price field
            if (success)
            {
                decimal minPrice = originalUnitPrice;
                decimal maxPrice = originalUnitPrice * (decimal)1.05;
                success = unitPrice != null;
                if (!success)
                    Result.Focus("UnitPrice", "Please enter the price.");
                else
                {
                    decimal price = Convert.ToDecimal(unitPrice.Value);
                    success = minPrice <= price && price <= maxPrice;
                    if (!success)
                        Result.Focus("UnitPrice", "This price must be between {0:c} and {1:c}", 
                            minPrice, maxPrice);
                }
            }
            // 5. validate Quantity field
            if (success)
            {
                success = quantity != null && quantity > 0;
                if (!success)
                    Result.Focus("Quantity", "The quantity must be greater than zero.");
            }
            // Validate Discount field
            if (success)
            {
                // 6. If value > 1, then convert value to percentage
                if (discount > 1)
                {
                    discount = discount / 100;
                    UpdateFieldValue("Discount", discount);
                }
                // 7. Confirm that Discount is between 0.00 and 0.99
                success = discount != null && discount >= 0.00 && discount <= 0.99;
                if (!success)
                    Result.Focus("Discount", 
                        "The discount must be between 0.00 and 0.99 (0% - 99%).");
            }
            // 8. Wrapping Up
            if (commandName == "Calculate" || !success)
                this.PreventDefault();
        }
    }
}

Visual Basic:

Imports MyCompany.Data
Imports System
Imports System.Data

Namespace MyCompany.Rules
    
    Partial Public Class OrderDetailsBusinessRules
        Inherits MyCompany.Data.BusinessRules
        <Rule("r100")> _
        Public Sub r100Implementation(ByVal orderID As Nullable(Of Integer),
                                      ByVal orderCustomerID As String,
                                      ByVal orderCustomerCompanyName As String,
                                      ByVal orderEmployeeLastName As String,
                                      ByVal orderShipViaCompanyName As String,
                                      ByVal productID As Nullable(Of Integer),
                                      ByVal productProductName As String,
                                      ByVal productCategoryCategoryName As String,
                                      ByVal productSupplierCompanyName As String,
                                      ByVal unitPrice As FieldValue,
                                      ByVal quantity As Nullable(Of Short),
                                      ByVal discount As Nullable(Of Single))
            ' 1. If the collected values are not valid then do not enforce the rule.
            '    The client library will instruct the user to correct the input.
            Dim success As Boolean = Me.ValidateInput()
            Dim commandName As String = Me.Arguments.CommandName
            Dim triggerFieldName As String = Me.Arguments.Trigger

            ' 2. Reset the base price for calculation of price limits 
            '    if the product selection has changed or if an existing
            '    data row has been selected for editing
            If Me.GetProperty("Session_ProductID") Is Nothing OrElse
                productID.Value.ToString() <> Me.GetProperty("Session_ProductID").ToString() Then
                Dim basePrice As Decimal = Convert.ToDecimal(unitPrice.Value)
                If Not triggerFieldName.Equals("ProductID") Then
                    basePrice = Convert.ToDecimal(unitPrice.OldValue)
                End If
                Me.SetProperty("Session_UnitPrice", basePrice)
                Me.SetProperty("Session_ProductID", productID)
                If triggerFieldName.Equals("ProductID") Then
                    quantity = 1
                    UpdateFieldValue("Quantity", quantity)
                    discount = 0
                    UpdateFieldValue("Discount", discount)
                    Result.Focus("Quantity")
                End If
            End If
            ' 3. Adjusting base price for an existing record
            Dim originalUnitPrice As Nullable(Of Decimal) =
                CDec(Me.GetProperty("Session_UnitPrice"))
            If originalUnitPrice Is Nothing OrElse originalUnitPrice = 0 Then
                originalUnitPrice = Convert.ToDecimal(unitPrice.OldValue)
                Me.SetProperty("Session_UnitPrice", originalUnitPrice)
            End If
            ' 4. validate Unit Price field
            If success Then
                Dim minPrice As Decimal = originalUnitPrice
                Dim maxPrice As Decimal = originalUnitPrice * CDec(1.05)
                success = unitPrice IsNot Nothing
                If Not success Then
                    Result.Focus("UnitPrice", "Please enter the price.")
                Else
                    Dim price As Decimal = Convert.ToDecimal(unitPrice.Value)
                    success = minPrice <= price AndAlso price <= maxPrice
                    If Not success Then
                        Result.Focus("UnitPrice",
                                     "This price must be between {0:c} and {1:c}",
                                     minPrice, maxPrice)
                    End If
                End If
            End If
            ' 5. validate Quantity field
            If success Then
                success = quantity IsNot Nothing AndAlso quantity > 0
                If Not success Then
                    Result.Focus("Quantity", "The quantity must be greater than zero.")
                End If
            End If
            ' Validate Discount field
            If success Then
                ' 6. If value > 1, then convert value to percentage
                If discount > 1 Then
                    discount = discount / 100
                    UpdateFieldValue("Discount", discount)
                End If
                ' 7. Confirm that Discount is between 0.00 and 0.99
                success = discount IsNot Nothing AndAlso discount >= 0.0 AndAlso discount < 1
                If Not success Then
                    Result.Focus("Discount",
                                 "The discount must be between 0.00 and 0.99 (0% - 99%).")
                End If
            End If
            ' 8. Wrapping Up
            If commandName = "Calculate" OrElse Not success Then
                Me.PreventDefault()
            End If
        End Sub
    End Class
End Namespace

The business rule is written in C# or Visual Basic. The fields are present in the arguments of the method. Changing the data type of the argument to FieldValue allows accessing additional properties of the field.

Click Browse button on the toolbar, sign in as admin/admin123% and navigate to Customers / Order Details page.

The business rule will be engaged as soon as a new record is being entered or an existing one is modified. The business rule will react to changes to the fields specified in the Context Fields property of UnitPrice when Calculate action is raised. The field UnitPrice depends on itself. It does not matter which application field is used to trigger the Calculate action. The only field that cannot trigger the calculation is ProductID. The Context Fields of a lookup will provide filtering information for the lookup window. Any field names in the Context Fields of ProductID will make the client library treat them as context filters, which will prevent users from seeing any products in the lookup window.

Business Rules provide a true abstraction level and separation from the user interface. The business rule is not actively selecting user interface elements to collect input values, which allows flexible modification of the presentation and the rule itself. The same business rule can service any number of data controller views regardless of the view types.

There are eight distinct steps in the business rule.

1. Initial Input Validation

The client library automatically performs basic validation of the entered values. The rule declares success variable, which is used to determine if any special validation needs to be applied to the fields.

The command causing the rule to execute is stored in commandName variable. The possible values are Calculate, Insert, or Update.

The rule also makes a note of the field that has triggered the business rule. The trigger field name will be known only when Calculate action is raised. The possible triggers are ProductID, UnitPrice, Quantity, and Discount.

This is an example of a basic validation that does not require custom coding.

2. Determination of The “Base” Price

The rule will memorize the last ProductID and UnitPrice in the properties of the data view instantiated on the browser page. The base price is used to ensure that users do not enter lesser values and to prevent the price inflation by more than 5%. If the product has just been changed, then the rule will reset values of fields Quantity and Discount and set the focus on the Quantity field.

This screen shot shows the form after the product selection.

3.  Adjusting Base Price for Existing Records

If the user is editing an existing record then the old (original) value of the UnitPrice is memorized in the data view properties.

4. Price Validation

The business rule figures the minimum and maximum price that can be entered by the user. If the price is blank, then the user is instructed to enter a value. If the price is out of range, then the user is forced to correct the problem.

This is the price validation in the form view.

This is how the price validation is performed in the data sheet view.

5. Quantity Validation

The rule ensures that a positive Quantity is entered.

6.  Automatic Conversion of Discount

The Discount column in Order Details table has the Single type. There is also a database constraint that requires the value to be between zero and one. The business rule will help the user by automatically converting the discount to a fraction of 100.

A user has entered a value greater than one in this screenshot.

The value is automatically converted when the user leaves the field.

7. Discount Range Validation

If the end user is trying to enter a particularly high discount that remains out of range even after automatic conversion, then the validation error is displayed.

8. Wrapping Up

The default behavior of the client library is to send the collected values to the server for processing by application. The business rule will prevent this from occurring. The business rule prevents server-side execution of Calculate action. It is also preventing server-side processing of Insert and Update if the validation has not been successful.