J Rivet by EchoMovement

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									                 Java Solutions for Enterprise Applications




JRIVET
Example 2 – Simple Data Entry Screen
C O D E   E X A M P L E S


The following examples outline creating simple screens using the jRivet framework. All
examples have been included in the preconfigured Windows Tomcat build. More complex
examples including tables, tree tables, and tabbed tables and time charts can be found in the
example applications. Examples of prompting, parameter passing, drill downs screens and
xml reports can also be found in the sample applications.



E X A M P L E   2



A Simple Data Inquiry Screen
In this tutorial we will be creating a very simple inquiry screen to display data from a
database table. The window will have record navigation buttons within the navigation
bar and data fields based on database table columns from a ‘Products’ table. Please note:
the creation of the ‘Products’ database table is beyond the scope of this document. For
this tutorial we will make the assumption that the table has been created and the JDBC
driver has access to it. Then when we are all done the window should look something
like the following:




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Step one is to create the XML document that will describe the attributes of the window.
The following document will render the above window:




A little more complex then our ‘Hello World’ example but still a basic XML screen
definition. Within the button-bar tags we have 3 record navigation buttons and another to
clear the screen. The ‘Find-It’ button will execute the Java method ‘getProducts’ from
the NwProducts class. Within the body of the document we have field definitions to
display the various table columns from the table. All the field objects in the above
document are text fields. The following table lists all the field, group and container
objects currently supported by jRivet XML:




Object Name                Tag                         Object Type




Check Box                  <CheckBox/>                 Field Component



Combo Box                  < ComboBox/>                Field Component




                                            2
Combo Item           < ComboItem/>          Data Element



List Box             < ListBox/>            Field Component



Image Box            <ImageBox/>            Field Component



Image Field          < ImageField/>         Field Component



Radio Button Group   <RadioButtonGroup/>    Field Container



Radio Button         < RadioButton/>        Field Component



Menu Explorer        < MenuExplorer/>       XML Container



Panel                < Panel/>              Container



Report Editor        < ReportEditor/>       XML Container



Script Editor        < ScriptEditor/>       XML Container



Menu Editor          <MenuEditor/>          XML Container



Spinner Field        < SpinnerField/>       Field Component



Tab Group            < TabGroup/>           Group Container



Tab Item             < TabItem/>            Container




                                        3
Table                 < Table/>                Table Container



Tab Table             < TabTable/>             Table Container



Tree Table            <TreeTable/>             Table Container



Table Check Box       <TableCheckBox/>         Field Component



Table Spinner Field   < TableSpinnerField/>    Field Component



Table Image Field     <TableImageField/>       Field Component



Table Combo Box       <TableComboBox/>         Field Component



Table Text Field      <TableTextField/>        Field Component



Text Area             <TextArea/>              Field Component



Text Field            <TextField/>             Field Component



Search Text Field     <SearchTextField/>       Search Component



Time Chart            <TimeChart/>             Chart Container



Time Chart Data       TimeChartData            Chart Field




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The following Java source snippet contains a ‘getProducts’ method.          This method is
wired to the ‘Find-it’ button in the above XML screen definition:




Let’s spend some time reviewing the above Java method. The DataSet object passed in
the method’s signature contains all data elements passed from the client. The string
‘keyField1’ is populated from the client’s DataSet object with the table key value used to
access the table. Next we create Result Set and SQL Statement objects used to access
the database. The DataAccess object passed in the method’s signature is used to get a
database connection and initialize the SQL Statement object. Next, the SQL Statement
object executes a query against the database. The returned table row is loaded into the
Result Set object.     A ‘for’ loop structure is then used to load the table row from the
Result Set into the client’s DataSet object. The complete method is encased in ‘try/catch’
structure to ensure the table is accessed without any glitches. The last step is to pass the
SQL Statement object back to DataAccess in order to close things off and clean up data
connects. The client’s DataSet object is passed back for client rendering.

Within the for loop structure we use a ‘tablefields’ object. The function of this object is
simply to get the data type for each column in the table. The field name and the data type
are both passed to DataAccess in order to read the value of each column in the returned
table row.

Similar methods need to be coded for the screens ‘nxtProducts’ and ‘prvProducts’
buttons. Once complete, compile the class and place it in the servers CLASSES folder.
Add appropriate menu tags to the menu XML document in order to access the new screen

Restarted your HTTP web server and load the jRivet application. If all went well you
should be able to select the new option and be presented with the new window.



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