CCF-to-J2C Architecture Migration

164 CCF-to-J2C Architecture Migration

The following section discusses the code that is needed to set up the desired

QoS for an IMS CCF application in a non-managed environment.

8.1.5 Setting up the QoS for a sample IMS CCF application

This section describes a sample application in which the Quality of Services of

connection pooling, transaction support, and security are set up for a simple IMS

CCF application.

This example is a catalogue Web application that handles orders and an item

inventory. The application has a servlet Web layer that uses proxy classes to

drive the back-end interaction. The methods of these classes manage the

desired function by interacting with IMS using the appropriate EAB command.

There are also specialized classes that are used to manage and set up the

desired QoS by the application components. The following application

components are described in detail:

򐂰 The method itemDetail() of the proxy class ItemHandler

򐂰 The class IMSBOManager that handles the setup of a specialized

JavaRuntimeContext with the desired QoS

򐂰 The helper class IMSConnectionManager that prepares the common

ConnectionManager and loads the ConnectionSpec, InteractionSpec, and

LogonInfo properties

򐂰 The Item bean that represents the item entity

The itemDetail() method in the ItemHandler class loads the input record, makes

the call to IMS, and analyzes the output record. Referring to the

ItemHandler.itemDetail() code in Example 8-1 on page 165:

򐂰 1a The IMSBOManager.initializeContext() method is called. It sets up the

JavaRuntimeContext associated with the current thread with the desired QoS

(connection pooling, transaction, and security).

򐂰 2a The EAB command is initialized and the RuntimeContext is bound to the

current JavaRuntimeContext.

򐂰 3a The static method IMSConnectionManager.initializeIMSCommand() loads

the IMSConnectionSpec, IMSInteractionSpec, and IMSLogonInfoItems

objects with the appropriate properties, read in from a properties file.

򐂰 4a The input record is instantiated and loaded with the appropriate values.

Important: in a managed environment, the application server manages the

QoS. In a non-managed environment, the application components have to

manage the QoS.

Chapter 8. Comparing CCF to J2C Architecture 165

򐂰 5a The call to IMS is executed.

򐂰 6a The output record is retrieved and type casted.

򐂰 7a If the desired output record has been obtained, then it is passed to a

custom Mapper class that loads the Item class.

򐂰 8a If the desired output record is not obtained, the DFS error message is

handled. (DFS is a component ID assigned to IMS; it is not an acronym.)

򐂰 9a In both cases, the current RuntimeContext resources are released with a

logical commit.

򐂰 10a In case an exception is cached (for example, if the time-out interval is

exceeded), resources are released with a logical rollback.

Example 8-1 Method ItemHandler.itemDetail()

public Item itemDetail(String companyCode, String itemCode)

throws Exception {

Item item = new Item();

RuntimeContext rt = null;

try{

// Runtime context initialization method 1a

initializeContext();

// Get an instance of the related EAB command 2a

ItemDetailCommand cmd = new ItemDetailCommand();

// Get the current RuntimeContext, that is

// the JavaRuntimeContext set in step 1

rt = RuntimeContext.getCurrent();

// Initialization of ConnectionSpec, InteractionSpec and LogonInfo 3a

IMSConnectionManager.initializeIMSCommand(cmd, rt.getLogonInfo());

// Get the input record from the command 4a

ItemDetailInRecord recordInput = cmd.getCeInput();

// Load the input record fields

recordInput.setWS__INP__LL((short)26);

recordInput.setWS__INP__TRANSACTION("UAMBPD01");// IMS Transaction name

recordInput.setWS__INP__COMP__CODE(companyCode);

recordInput.setWS__INP__ITEM__CODE(itemCode);

// Make the call to IMS 5a

166 CCF-to-J2C Architecture Migration

cmd.execute();

// Get the output record and the DFSMsg 6a

ItemDetailOutRecord recordOutput = cmd.getCeOutput0();

DFSMsg error = cmd.getCeOutput1();

// Get the output record

Object o = cmd.getOutput();

// Check if we’ve obtained the desired output record or a DFS error

if ( java.beans.Beans.isInstanceOf(o, ItemDetailOutRecord.class))

{

// We have the desired output record 7a

// Get an instance of the related Mapper class

ItemDetailMapper mapper = new ItemDetailMapper() ;

// Map the output record to the item bean

item = mapper.mapFromOutput(recordOutput);

// Free the resources pooled to the current thread (no IMS call) 9a

commit();

}

else

{

// We have a DFS Error Message record 8a

// Free the resources pooled to the current thread (no IMS call) 9a

commit();

//Handle the DFS error message in the preferred way

}

}

// Something unexpected happened, i.e. IMS connection timeout exeeded 10a

catch (Exception e){

// Free the resources pooled to the current thread (no IMS call)

rollback();

// Handle the exception in the preferred way

}

return item;

}