Getting Started with eQ!™

Creating a Client

The final step shows how to use the Supplier business object and the scripting from a client perspective. Two examples will be shown, one accessing the script engine in a JSP by using the supplied taglib, and the other in code, such as from a JUnit test. It should be noted that usually you will not need to directly access the script engine. Instead, access will be provided by an eQ!™-supplied adapter, such as when using the Struts web framework; however, it is shown here for clarity and understanding purposes.

JSP - This example uses the eQ!™ taglib for executing the script engine. It also shows usage of the JSTL (Java Standard Tag Library) for outputting the properties of the Supplier objects. The usage of the taglibs is highlighted:

<!-- Import the eQ!™ taglibrary -->
<%@ taglib uri="/WEB-INF/eq.tld" prefix="eq" %>
<!-- Import the JSTL taglibrary -->
<%@ taglib uri="/WEB-INF/c.tld" prefix="jstl-core" %>
<html>
    <body>
        <p align="center"><b>Suppliers</b></p>
        <!-- Setup the script tag -->
        <eq:script scriptName="retrieve_business_object_set">
            <!-- Setup the persisterId we want to use -->
            <eq:script-attribute name="persisterId" value="default" />
            <!-- Execute the script -->
            <eq:script-execute />
            <!-- Put the set into the pageContext. This is currently required
                 so that the JSTL tags can 'see' our BusinessObjectSet.
            -->
            <% pageContext.setAttribute( "set", scriptResponse.getAttribute( "supplierSet" ) ); %>
            <!-- Create an HTML table showing the results -->
            <table>
                <tr>
                    <td>Name</td>
                    <td>Street</td>
                    <td>City</td>
                    <td>State</td>
                    <td>Zip</td>
                </tr>
                <!-- Loop through the set, outputting the properties of each Supplier -->
                <jstl-core:forEach var="supplier" items="${set.iterator}" >
                    <tr>
                        <td><jstl-core:out value="${supplier.name}" /></td>
                        <td><jstl-core:out value="${supplier.street}" /></td>
                        <td><jstl-core:out value="${supplier.city}" /></td>
                        <td><jstl-core:out value="${supplier.state}" /></td>
                        <td><jstl-core:out value="${supplier.zip}" /></td>
                    </tr>
                </jstl-core:forEach>
            </table>
    </body>
</html>

Java Code - Here is some code with comments inline that is set up as a JUnit test method:

public void testSupplierSetRetrieve() throws Exception {
    ScriptEngine engine = null;

    // Get a reference to the engine
    engine = (ScriptEngine)SystemContainer.getManager().lookup(ScriptEngine.ROLE);

    // Create a request
    ScriptRequest request = new ScriptRequest();

    // Set the name of the script to execute
    request.setScriptName("retrieve_business_object_set");

    // Create a Hashtable for the params used by the SQL statement
    java.util.Hashtable params = new java.util.Hashtable();
    params.put( "value", "Joe" );

    // Put the params into the request
    request.setAttribute( "params", params );

    // Put the persisterId into the request
    request.setAttribute( "persisterId", "bySupplierName" );

    // Execute the request and get a response
    ScriptResponse response = engine.execute( request );

    // Get the set out of the response
    BusinessObjectSet set = (BusinessObjectSet)response.getAttribute( "bo_set" );
    assertNotNull( "No set was returned", set );
    assertTrue( "The set is empty", set.getRowCount() > 0 );

    // Iterate through the set and display each Supplier
    Iterator it = set.getIterator();
    while( it.hasNext() ) {
        Supplier supplier = (Supplier)it.next();
        System.out.println( supplier.getName() );
        // Or using the symbolic means of property access:
        System.out.println( supplier.getValue( "name" ) );
    }
}

Using this example code, and the SQL defined in the Set Persister Config step, the resulting SQL call would look something like this:
     SELECT supplier_id, name, street, city, state, zip
     FROM Suppliers
     WHERE name LIKE '%Joe%'

 

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