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EGL Programming - Data Parts and Assignment Statements - 2 - DataItems

EGL Programming - Data Parts and Assignment Statements - 2 - DataItems. These slides walk you through the terms and concepts around declaring EGL variables using DataItem definitions. This learning module also covers EGL data properties in-depth.

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EGL Programming - Data Parts and Assignment Statements - 2 - DataItems

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  1. EGL Programming - Data Parts and Assignment Statements - 2 - DataItems These slides walk you through the terms and concepts around declaring EGL variables using DataItem definitions. This learning module also covers EGL data properties in-depth.

  2. 2. DataItems – Defining Custom Types or “Domain Definitions” EGL supports the creation of new types for your application domains, that consist of extended semantic definitions for common application development requirements through a language abstraction known as DataItems. • A DataItem is a single element definition that associates a primitive data type with extended properties. Using DataItems you can create an operational “data dictionary” for your application with business rules entered into a central repository (a file of DataItems), coded and tested once and reused throughout. • Examples: dataitem Password String { DisplayUse=Secret, DisplayName = "Enter Password", InputRequired = yes } end • Defines a Password type as a string, that: • Displays asterisks when bound to a JSF control • The default label it creates is “Enter Password:” • The user must enter a value, or the EGL generated code – will return an error message dataitem OrderAmount Money(9, 2) { NumericSeparator = yes, ValidValues = [1.00, 999999.99] } end dataitem StateAbbrev String { ValidValues = ["AK","AL","CT","DE","NC","TX","NJ"] } end Can you figure out what semantic validations the OrderAmount and StateAbbrev DataItems provide?

  3. Declaring an EGL DataItem – Syntax Format Prototype: DataItem <DataItemName> <primitive_type> { EGL Properties } end Example: DataItem Last_Name_Inp string { displayUse = input, displayName = “Enter Last Name”, inputRequired = yes, validatorFunction = lnameValFunc } end • Dragging a variable of this type onto a web page will create an input control • The label of this control will be: “Enter Last Name:” • This is not an optional entry field for users • A function in the JSFHandler named: lnameValFunc will be invoked automatically, to ensure that the data entered conforms to more complex business rules 1. 2. 3. 4.

  4.  F3  F3 I’ve Already Used DataItems + F3 (Open on Selection) Yes! When you imported the tables with the Data Access Application wizard, that process created a DataDefinitions.egl file – with default DataItems that were referenced in the fields of the records used in allcustomers2, updatecustomer2, allorders, etc. F3 (Best Practice) Edit allcustomers2. egl. Highlight the Customer record definition and press F3 (this will open the record definition in the Content Area). You can then highlight a DataItem (type) in the record, and press F3 to see the original DataItem definition.

  5. DataItems – Best Practices – 1 of 2 – Generic/Specific Domains • DataItem Best Practices fall into two basic categories: • Individual/specific field domain definition • Generic domain definition Specific (individual field) DataItem Definitions: - You can define an individual DataItem (or most of the DataItems) for individual fields in Records and variables throughout your application***Notes - Typically, you would embed as many domain-specific customized properties as you can, when taking this approach dataItem Password String {DisplayUse=Secret,DisplayName="Enter Password", InputRequired=yes} end dataItem OrderAmount Money(8,2) {NumericSeparator=yes, ValidValues=[1.00, 999999.99]} end dataitem OrderDetails String {DisplayName="Order Details"} end dataitem CurrentStates String {ValidValues = ["AK","AL","CT","DE","NC","TX","NJ"]} end dataitem CustID int {DisplayUse=outPut,DisplayName="Customer ID",ValidValues=[1,999999]} end Generic (reusable/domain) DataItem Definitions - You can define “global” DataItem types for domains you use repeatedly throughout your application. Ex. MoneyType (9,2), DateType (dateFormat, etc.) - You would probably declare a minimal number of generic/common properties for such definitions, and then add to/over-ride when you declare variables of these types (see next slide) dataitem NameType String { upperCase = yes} end dataitem IDType int { DisplayUse=outPut, DisplayName="ID" } end dataitem MoneyType Money(8, 2) { NumericSeparator = yes, sign=leading } end dataitem DateType Date {dateFormat=eurDateFormat} end dataitem StateType char(2) {ValidValues = ["AK","AL", "AS", "AR", "AZ", "CA", "CO", "CT"…]}

  6. DataItems – Best Practices – 2 of 2 – Over-riding Properties • For any use (reference to) a DataItem type, in one of your logic parts, you may: • Insert new properties – which are added to the property list defined in the DataItem • Over-ride properties – which forces the EGL tooling to substitute your new property, for a defined property of the same type in the Domain Definition Example: 1. Initial DataItem definition: 2. Variable of type: Password – over-riding DisplayName and DisplayUse, adding UpperCase= 3. Drag field3 (with over-ridden properties) on a web page. Note design and run-time results: Over-Ridden DisplayUse Over-Ridden DisplayName UpperCase=yes

  7.  EGL Properties – Leveraging DataItems  You specify useful business semantics for a DataItem by coding one or more EGL Properties. Properties are powerful ways of expressing business rules for your DataItems. They are coded with the following name/value pair syntax: { <property>=<value>, <property>=<value>, …} Considerations: • Properties exist for: • Data Parts (we are mostly interested in Data Part properties here) • Logic Parts • UI Parts (Terminal User Interface forms) • DataItems allow you to: • Consolidate like or related properties into a single new, custom “type” • Create unique “one-off” types for fields in your application Let’s have a look at properties within the help system. From the Help menu, search on: Master list of all EGL properties

  8. EGL Properties – Two Categories Formatting and U.I. display • upperCase / lowerCase – translates Alphabetic characters to upper case • zeroFormat – display a zero (yes) or blank (no – default) on pages for values of zero • Sign – provides a negative indicator character, for numeric values less than zero being displayed • displayName – allows you to customize the label for the variable, when dragged onto a page • dateFormat – allows you to custom-format a date field’s display • fillCharacter – over-rides the default fill character (blanks) for fields • numericSeparator – adds commas to Money and numeric output fields Validation and Data Entry (input/edit properties) • All of these Properties are used to trigger server-side generated code, that automatically applies business logic rules – consistently, to user data entry values, and automatically returns errors if the data tests false • inputRequired (yes/no) – forces users to enter non-blank data in a field upon input • validValues […] – allows you to provide a list of values which user input is tested against*** Notes • validatorTable = DataTablename – Names an EGL DataTable that contains values which the user input must adhere to • validatorFunction = FunctionName – allows you to name a custom JSF Handler function that will be called automatically to test user input against. Use for complex data entry edit requirements • onValueChangeFunction – similar to validatorFunction, except that this function is only invoked if users actually change values on a field in a page

  9. EGL Properties and Content Assist and Source Assistant too! What if you don’t remember the syntax for a particular EGL Property? Two options: 1. By placing your cursor between the curly braces, and pressingCtrl+Shift+Z - You invoke Source Assistant – wizard-driven method of selecting properties 2. Ctrl/Spacebar - You can let Content Assist bring up a list of all variable properties 

  10. Declaring EGL Variables That Reference a DataItem Type After a DataItem has been defined and saved you can refer to it as the “TYPE” of a variable in a Logic Part. And the EGL tooling “copies” all of the extended semantic properties of the DataItem definition to your variable declaration when you generate. • This allows you to declare variables of <DataItemType>; - using Content Assist (in an EGL Logic Part) //VariableName DataItem (new variable type) pWord Password; ordAmt OrderAmount; • Note that the DataItem definition (in the above example, Password and OrderAmount) must be available within the Namespace – meaning you may need an import statement for the folder that contains the EGL source file with the DataItem definitions you wish to use. Ex. import data.*;

  11. Workshops for DataItem Topic – 1 of 2 Using the RBD tooling and EGL, create the EGL DataItems and their custom properties as shown here. Steps: 1. Create a new EGL source file named: DataDictionary in the \data\ directory under \EGLSource\ 2. Into this file, Copy and paste the following DataItem definitions (below the package statement) //A DataItem AgeItem smallint {displayName="Enter Age", validValues=[[18,99]], DisplayUse = input} end //D DataItem DateOfBirthItem Date {displayName="Enter Date of Birth", dateFormat=usaDateFormat} end //H Dataitem HeightItem Decimal (3,1) {displayName="Enter Height", value=0.0} end //N DataItem NameItem string {displayName="* Enter Name",inputRequired=yes} end //P DataItem PhoneItem char(12) {displayName="* Enter Phone",inputRequired = yes} end //S DataItem SalaryItem decimal(8,2) {displayName="Enter Salary",currency=yes, validValues=[[20000.00,99999.99]], DisplayUse = Input} end DataItem selItem boolean {value=false, displayname="Generic Boolean"} end DataItem StateItem char(2) {validValues=["CA","CT","NJ","NY","NC"]} end //Z DataItem ZipItem char(5) {displayName="Enter Zip", validValues=[["00001","90210"]]} end 3. Modify the displayName and validValues properties. 4. Change the dateFormat from usaDateFormat to another alternative. Note – use Content Assist to help you discover and code a valid date format syntax)

  12. Workshops for DataItem Topic – 2 of 2 5. Return to your newaccount JSFHandler, and modify the EGL data types, as shown here  …referencing DataItems instead of Primitive types in most cases • Use Content Assist to speed your work! 6. Press Ctrl/Sto save

  13. Topic Summary • Now that you have completed this topic, you should be able to: • Define EGL DataItems • Describe several useful properties of DataItems • Use Content Assist and Source Assistant to create DataItem properties • Code variables that reference new DataItem types • Over-ride EGL properties defined in DataItems for variables declarations

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