8 Oracle WebLogic Tuxedo Connector JATMI VIEWs

Overview of Oracle WebLogic Tuxedo Connector VIEW Buffers

Oracle WebLogic Tuxedo Connector allows you to create a Java VIEW buffer type analogous to an Oracle Tuxedo VIEW buffer type derived from an independent C structure. This allows Oracle WebLogic Server applications and Oracle Tuxedo applications to pass information using a common structure. Oracle WebLogic Tuxedo Connector VIEW buffers do not support FML VIEWs or FML VIEWs/Java conversions.

How to Create a VIEW Description File

Your Oracle WebLogic Server application and your Oracle Tuxedo application must share the same information structure as defined by the VIEW description. The following format is used for each structure in the VIEW description file:

$ /* VIEW structure */
VIEW viewname 
type cname fbname count flag size null 

where

• The file name is the same as the VIEW name.

• You can have only one VIEW description per file.

• The VIEW description file is the same file used for both the Oracle WebLogic Tuxedo Connector viewj compiler and the Oracle Tuxedo viewc compiler.

• viewname is the name of the information structure.

• You can include a comment line by prefixing it with the # or $ character.

• The following table describes the fields that must be specified in the VIEW description file for each structure.

type 

cname 

fbname 

count

flag

size

null

VIEW infoenc
#type    cname    fbname  count flag size null
float    amount   AMOUNT  2     -    -    0.0
short    status   STATUS  2     -    -    0
int      term     TERM    2     -    -    0
char     mychar   MYCHAR  2     -    -    -
string   name     NAME    1     -    16   -
carray   carray1  CARRAY1 1     -    10   -
dec_t    decimal  DECIMAL 1     -    9    - #size ignored by viewj/viewj32
END

How to Use the viewj Compiler

To compile a VIEW typed buffer, run the viewj command, specifying the package name and the name of the VIEW description file as arguments. The output file is written to the current directory.

To use the viewj compiler, enter the following command:

java weblogic.wtc.jatmi.viewj [options] [package] viewfile

To use the viewj32 compiler, enter the following command:

java weblogic.wtc.jatmi.viewj32 [options] [package] viewfile

The arguments for this command are defined as follows:

package

viewfile

For example:

• A VIEW buffer is compiled as follows:

  java weblogic.wtc.jatmi.viewj -compat_names examples.wtc.atmi.simpview infoenc
  

• A VIEW32 buffer is compiled as follows:

  java weblogic.wtc.jatmi.viewj32 -compat_names -modify_strings
  examples.wtc.atmi.simpview infoenc
  

How to Pass Information to and from a VIEW Buffer

The output of the viewj and viewj32 command is a .java source file that contains set and get accessor methods for each field in the VIEW description file. Use these set and get accessor methods in your Java applications to pass information to and from a VIEW buffer.

The AssociatedFieldHandling flag is used to specify if the set and get methods use the values of the associated length and count fields if they are specified in the VIEW description file.

• set methods set the count for an array field and set the length for a string or carray field.

• Array get methods return an array that is at most the size of the associated count field.

• String and carray get methods return data that is at most the length of the associated length field.

Use one of the following to set or get the state of the AssociatedFieldHandling flag:

• Use the -associated_fields option for the viewj and viewj32 compiler to set the AssociatedFieldHandling flag to true.

• Invoke the void setAssociatedFieldHandling(boolean state) method in your Java application to set the state of the AssociatedFieldHandling flag.

  • If false, the set and get methods ignore the length and count fields.

  • If true, the set and get methods use the values of the associated length and count fields if they are specified in the VIEW description file.

  • The default state is false.

• Invoke the boolean getAssociatedFieldHandling() method in your Java application to return the current state of AssociatedFieldHandling.

How to Use VIEW Buffers in JATMI Applications

Use the following steps when incorporating VIEW buffers in your JATMI applications:

1. Create a VIEW description file for your application as described in How to Create a VIEW Description File.

2. Compile the VIEW description file as described in How to Use the viewj Compiler.

3. Use the set and get accessor methods to pass information to and receive information from a VIEW buffer as described in How to Pass Information to and from a VIEW Buffer.

   See the examples/wtc/atmi/simpview/ViewClient.java file in your Oracle WebLogic Server distribution for an example of how a client uses accessors to pass information to and from a VIEW buffer.

4. Import the output of the VIEW compiler into your source code.

5. If necessary, compile the VIEW description file for your Oracle Tuxedo application and include the output in your C source file as described in "Using a VIEW Typed Buffer" in Programming a Tuxedo ATMI Application Using C at http://download.oracle.com/docs/cd/E13203_01/tuxedo/tux100/pgc/pgbuf.html.

6. Configure a WTCServer MBean with a Resources Mbean that specifies the VIEW buffer type (VIEW or VIEW32) and the fully qualified class name of the compiled Java VIEW description file. The class of the compiled Java VIEW description file should be in your CLASSPATH.

7. Build and launch your Oracle Tuxedo application.

8. Build and launch your Oracle WebLogic Server Application.

String toConvert = new String("hello world");
TypedFML32 MyData = new TypedFML32(new MyFieldTable());
Long d1 = new Long(1234);
Float d2 = new Float(12.32);
MyView data = new myView();
FviewFld vfld;
data.setamount((float)100.96);
data.setstatus((short)3);
vfld = new FviewFld("myView", data);

try {
  myData.Fchg(MyFieldTable.FLD0, 0, toConvert);
  myData.Fchg(MyFieldTable.FLD1, 0, 1234);
  myData.Fchg(MyFieldTable.FLD2, 0, d2);
  myData.Fchg(MyFieldTable.myview, 0, vfld);
} catch (Ferror fe) {
  log("An error occurred putting data into the FML32 buffer.  The error is " + fe);
}

try {
  myRtn = myTux.tpcall("FMLVIEW", myData, 0);
} catch(TPReplyException tre) {
….
}
TypedFML32  myDataBack = (TypedFML32)myRtn.getReplyBuffer();
 Integer myNewLong;
 Float myNewFloat;
 myView View;
 String myNewString;

try {
  myNewString = (String)myDataBack.Fget(MyFieldTable.FLD0, 0);
  myNewLong = (Integer)myDataBack.Fget(MyFieldTable.FLD1, 0);
  myNewFloat = (Float)myDataBack.Fget(MyFieldTable.FLD2, 0);
  vfld = (FviewFld)myDataBack.Fget(MyFieldTable.myview, 0);
  view = (myView)vfld.getViewData();
} catch (Ferror fe) {
  ….
}

*base 20000 
#name    number  type   flags   comments
FLD0     10      string -       -
FLD1     20      long   -       -
FLD2     30      float  -       -
myview   50      view32 -       defined in View description file

Using the XmlViewCnv Class for XML to and From View/View(32) Translation

Use the XmlViewCnv class to perform XML to View /View(32) or View/View(32) to XML translation. The following code listing is an example that uses the XmlViewCnv class for conversion to and from XML buffer formats.

import examples.wtc.atmi.simpview.infoenc; // View class import
weblogic.wtc.gwt.XmlViewCnv; 
import weblogic.wtc.jatmi.TypedBuffer;

public class xml2view
{
   public static void main(String[] args) {
      String xmlDoc = 
      "<VIEW32><infoenc><amount>1000.0</amount><infoenc></VIEW32>";

      infoenc convertMe = new infoenc();
      convertMe = (infoenc) XmlViewCnv.XMLToView(
         xmlDoc,
         convertMe.getClass(),
         convertMe.getSubtype());

      convertMe = (infoenc) echo.Echo(convertMe);

      result = XmlViewCnv.ViewToXML(
         (TypedBuffer) convertMe, 
         convertMe.getClass(), 
         true);

      System.out.println(result);
   }
}