Create Forms in WebUI

Note

This article was originally posted to the AIMMS Tech Blog.

Use the AIMMS WebUI Forms framework to create modern-looking forms for data entry.

Three basic actions are needed:

• Select the identifiers for which you want to provide data
• Write the code to perform checks
• Draw the form on the screen by selecting a few widgets

This makes the AIMMS WebUI Forms framework an efficient method to create forms from the model builder’s perspective.

The AIMMS WebUI Forms framework follows CRUD and thus provides your users the ability to:

• Create new data
• Read existing data
• Update existing data
• Delete invalid data

This image below illustrates a form in the AIMMS WebUI.

New or modified data is entered (red rectangle), and once it passes the checks, it is copied to the actual model identifiers as if it were a single transaction.

To properly implement such a form, several identifiers are needed. Each of them inherits some properties from the corresponding model identifier. In addition, AIMMS code is needed for checking and for copying/deleting.

The AIMMS WebUI Forms framework minimizes effort for developers by creating the needed additional identifiers, and generating code for copying, deleting and the repetitive part of checking.

Let’s use an example to show how to deploy this framework in order to create an advanced form. This example is part of an inventory management application, where data of a Stock Keeping Unit is entered and maintained.

1. Prepare the project for WebUI
2. Create the declarations and procedures support the form
3. Add procedure to create a new element
4. Add procedure to check data for an element
5. Link the callbacks to AIMMS WebUI Forms framework
6. Draw the form on the WebUI canvas:
7. Add user-friendly labels to facilitate proper user entry

Prepare the project for WebUI

In order to add forms to your application, you will need to prepare your application for the WebUI by adding the system libraries AimmsProLibrary and AimmsWebUI to your application. This can be done using the AIMMS Library manager. This action needs to be done only once per application.

1 New project with system libraries

You may note the additional libraries. An application started with the AimmsWebUI system library, will also create the libraries AimmsWebUIRuntime and DataChangeMonitorRuntime. These two libraries are created and maintained by the library AimmsWebUI.

The targets of the form to be created are the model identifiers in which we want to store valid data. We continue by declaring such identifiers. In our running example, stock keeping unit (SKU) data is maintained. In order to limit the size of the example, per SKU we only maintain the following properties:

• manufacturer (name),
• volume (liter),
• color (in color set), and
• stock (non-negative integer).

Thus we declare the corresponding model identifiers as follows:

2 sets and parameters for model

Create the declarations and procedures

We need the following extra declarations in order to work with the forms:

• When we are editing existing data, we want to know for which element that is. The WebUI forms uses a binary parameter for this. In our example we will call this binary parameter P_SKUFORM_Selection(sku).
• Each SKU needs a unique identification before it can be added to the set. This identification can simply be a unique (non-descriptive) number or a name. In our example we use a name. That is why we add an extra string parameter: SP_SKUFORM_InternalName(sku). Actually, this is just another property, modeled here via a string parameter.
• A procedure to create a new element. In our running example, this will be pr_SKUFORM_Create. This is a callback procedure; it will be called by the AIMMS WebUI Forms framework.
• A procedure that validates the newly entered or modified data. In our running example, this will be pr_SKUFORM_Check. This is also a callback procedure; it will be called by the AIMMS WebUI Forms framework.
• A procedure that links the above declarations and initializes a WebUI Form. In our running example, this will be pr_SKUFORM_Setup. It needs to be called once by the application before the form is shown in the browser.

The above declarations are shown below, in the AIMMS model explorer:

Procedure callback declarations

Both callbacks have an argument named formData. This argument communicates the strings entered by the application user. This argument is declared as follows:

StringParameter formData {
    IndexDomain: webui::ffn;
    Property: Input;
}

Here the index webui::ffn is an index in the set webui::AllFormFieldNames. This index and set are available in the AimmsWebUI system library and will be linked to the model identifiers later on.

The set webui::AllFormFieldNames is a subset of AllIdentifiers, which allows us to link easily to the model identifiers at hand.

In the following three steps we will discuss the selected details of these three procedures.

Create a new element

This procedure is expected to create a new element in the set for which the form is setup. In our running example that is S_StockKeepingUnit. You can use element names different from the literal text entered by the user, but our example does not. Please note that, before this procedure is called, the name was already verified by the check procedure discussed in the next section.

SetElementAdd(S_StockKeepingUnit,anSKU,
             formData('SP_SKUFORM_InternalName'));
newSKUName := formData('SP_SKUFORM_InternalName');

Here, anSKU is a local element parameter with range S_StockKeepingUnit.

Check data for an element

The check procedure is called as soon as we save the data. It has two arguments, an input argument that contains the strings entered by the user, and an output argument that contains any corresponding error messages about these strings. The data accepted only if there are no errors.

Selected checks of this procedure are presented below.

The first if in the code below checks new element names. A new name does not exist; and this corresponds to an empty P_SKUFORM_Selection. The second if in the code below checks whether the name already exists.

if ( not exists[ i_SKU | P_SKUFORM_Selection(i_SKU) ] ) then
    if ( StringToElement(S_StockKeepingUnit, formData('SP_SKUFORM_InternalName')) ) then
        validationErrors('SP_SKUFORM_InternalName') :=
                      webui::CreateValidationError("validation-error-name-already-exists");
    endif;
endif;

Any errors are logged by the function webui::CreateValidationError.

Next we check that the manufacturer is specified and the length is at least 3.

if (StringLength(formData('SP_Manufacturer')) < 3) then
     validationErrors('SP_Manufacturer') :=
           webui::CreateValidationError("validation-error-not-a-valid-manufacturer-name");
endif;

Lastly we check that the stock available is a non-negative integer:

block
    p_loc_Stock := Val(formData('P_Stock'));
    if ( ( p_loc_Stock < 0 ) or ( mod(p_loc_Stock,1)  0 ) ) then
        validationErrors('P_Stock') :=
         webui::CreateValidationError("validation-error-not-a-valid-availability");
    endif;
onerror err do
    validationErrors('P_Stock') :=
        webui::CreateValidationError("validation-error-not-a-valid-availability");
    errh::MarkAsHandled(err);
endblock;

Note the use of error handling here, as the AIMMS intrinsic functions Val and Mod may throw an error upon invalid input.

The next step details the last procedures required for the form.

Linking callbacks to WebUI Forms framework

In our running example, we use the procedure pr_SKUFORM_Setup as the procedure which links the model identifiers, SKUFORM procedures and the actual form in WebUI together. This procedure is called at the end of the StartupProcedure in order to make sure it is called before the form is opened for the first time.

There are two steps in this procedure. In the first step we name the model identifiers that identify the fields in the form (here FormFields is a subset of AllIdentifiers):

FormFields := data {
    'SP_SKUFORM_InternalName',
    'SP_Manufacturer',
    'P_Volume',
    'EP_Color',
    'P_Stock'};

In the second step, the actual linking is done:

webui::SetupForm(
    formId             :  "SKUForm",
    selInMaster        :  'P_SKUFORM_Selection',
    detailsIdentifiers :  FormFields,
    validationHandler  :  'pr_SKUFORM_Check',
    newEntryCallback   :  'pr_SKUFORM_Create');

Draw the form on the WebUI canvas

After starting the AIMMS WebUI (AIMMS Menu – Tools – Start WebUI) and opening the browser page localhost:12001/example, we can create the necessary widgets:

• A legend widget, contents: P_SKUFORM_Selection
• A scalar widget, contents: webui_runtime::SKUForm_P_Stock, webui_runtime::SKUForm_EP_Color, webui_runtime::SKUForm_P_Volume, webui_runtime::SKUForm_SP_Manufacturer, webui_runtime::SKUForm_SP_SKUFORM_InternalName
• Three button widgets linking to the procedures webui_runtime::SKUForm_SaveForm, webui_runtime::SKUForm_NewEntry, webui_runtime::SKUForm_DeleteEntry and name them Save, Create, and Delete respectively.

This will result in the following form:

4 Basic widget placing

As the names in this form are a bit opaque to the average user, we will try to make them more appealing in the next step.

Create user-friendly names

Phrase adapting in the WebUI is achieved via translation files. In our running example we adapt using InventoryManagement\WebUI\resources\languages\skuform-messages.properties, with the following contents.

SKUForm_SP_SKUFORM_InternalName = Name
SKUForm_SP_Manufacturer = Manufacturer
SKUForm_P_Volume = Volume
SKUForm_EP_Color = Color
SKUForm_P_Stock = Stock

form-enter-SP_SKUFORM_InternalName =
form-enter-SP_Manufacturer =
form-enter-P_Volume =
form-enter-EP_Color =
form-enter-P_Stock =

no-P_SKUFORM_Selection-selected =

validation-error-min-length = A name must be at least two characters long.
validation-error-name-already-exists = A person with this name already exists.
validation-error-required-field = Required field.
validation-error-not-a-valid-Volume = Not a valid volume.
validation-error-not-a-valid-Stock = Not a valid stock.

With this phrase adapting, the form now looks as follows:

4 Basic widget placing - translated names

Example project

You can find this example in the AIMMS Example repository at AIMMS Examples

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Last Updated: May, 2019