Fujitsu J Adapter Class Generator User Manual
J Adapter Class
Generator User’s Guide
Seventh Edition: August 2005
The contents of this manual may be revised without prior notice. No part of this document may
be reproduced or transmitted in any form or by any means, electronic or mechanical, for any
purpose, without the express written permission of Fujitsu Limited.
© 1996-2005 Fujitsu Limited. All Rights Reserved.
Preface
The "NetCOBOL
(adapter class) used to call a Java class. Using the adapter class thus generated
makes the Java class library available from COBOL.
A Java runtime environment must be installed to execute the generator or the
adapter class generated. See "
J Adapter Class Generator
Preparations
" is a tool that generates a COBOL class
" for required products.
Purpose of This Manual
This manual provides information on how to enable COBOL programs to use Java
classes. The information includes the ways of creating adapter classes, writing
programs, and running the programs.
Refer to the
information on how to develop programs using Fujitsu NetCOBOL, refer to the
NetCOBOL User's Guide
Fujitsu NetCOBOL Language Reference
.
for the COBOL syntax. For
Fujitsu
Intended Readers
This manual is intended for persons who develop COBOL programs using Java
classes.
Prerequisites
Readers are required to have the following knowledge to read this manual:
Basic knowledge of COBOL syntax •
• • Basic knowledge of COBOL object-oriented programming
Basic knowledge of Java
Organization of This Manual
This manual consists of the following chapters:
Chapter 1. Outline of J Adapter Class Generator
Chapter 1 explains the function and operating environment of the J adapter class
generator.
Chapter 2. J Adapter Class Generator Framework
Chapter 2 explains the framework of the J adapter class generator.
Chapter 3. Developing Programs
Chapter 3 explains how to develop programs that uses Java classes.
Chapter 4. Using the Generator Command
Chapter 4 explains how to use the generator command (java2cob).
NetCOBOL J Adapter Class Generator User's Guide 3
Chapter 5. Adapter Class Reference
Chapter 5 provides detailed information on the FJ-JAVA-BASE, FJ-JAVA-CONTROL
and FJ-JAVA-ERROR classes provided by the J adapter class generator, and adapter
classes generated by the J adapter class generator.
Appendix A. Message List
Appendix A explains the messages output by the J adapter class generator, including
the operator responses to the messages.
Appendix B. Exception Type List
The Appendix B describes the types of exception generated by the J adapter class
generator and their remedial measures.
How to Use This Manual
When using the J adapter class generator for the first time, begin to read from
Chapter 1. Chapter 1 provides an outline of the J adapter class generator, Chapter 2
explains the framework, and Chapter 3 explains the procedures from development to
execution.
Chapters 4 and 5 provide detailed information on how to use commands and classes.
Read these chapters for program development.
The Appendix A describes the messages that are output form the J adapter class
generator and the Appendix B describes the exception types that the J adapter class
generator sets. Read them as necessity requires.
Product Names
Product Name Abbreviation
Microsoft® Windows® 98 Operating System Windows® 98
Microsoft® Windows® Me Operating System Windows® Me
Microsoft® Windows NT® Workstation Operating System Version
4.0
Microsoft® Windows NT® Server Network Operating System,
Version 4.0
Microsoft® Windows NT® Server Network Operating System,
Enterprise Edition Version 4.0
Microsoft® Windows® 2000 Professional Operating System Windows® 2000 or
Microsoft® Windows® 2000 Server Operating System Windows® 2000 or
Microsoft® Windows® 2000 Advanced Server Operating System Windows® 2000 or
Microsoft® Windows® 2003 Server Operating System Windows® 2003 or
Windows® 98, Windows® Me, Windows NT®, and Windows® 2000 Windows
Windows NT® or
Windows NT® 4.0
Windows NT® or
Windows NT® 4.0
Windows NT® or
Windows NT® 4.0
Windows® 2000
Professional
Windows® 2000
Server
Windows® 2000
Server
Windows® 2000
Server
®
4 NetCOBOL J Adapter Class Generator User's Guide
Registered Trademarks
The registered trademarks appearing in this manual are as follows:
Microsoft, Windows, and Windows NT are registered trademarks of Microsoft
Corporation in the U.S. and other countries.
Java and other trademarks including Java are trademarks of Sun Microsystems, Inc.
in the U.S. and other countries.
J Adapter Class Generator User's Guide
5
6 NetCOBOL J Adapter Class Generator User's Guide
Contents
Chapter 1. Outline of J Adapter Class Generator.........................................9
What is the J Adapter Class Generator?...............................................................10
What the J Adapter Class Generator Can Do........................................................11
What the J Adapter Class Generator Cannot Do ...................................................11
Preparation.......................................................................................................12
Chapter 2. Adapter Class Generator Framework .......................................13
Adapter Class....................................................................................................14
Adapter Object..................................................................................................15
Chapter 3. Developing Programs ...............................................................17
Creating Adapter Classes ...................................................................................18
Developing an Application That Uses an Adapter Class .........................................22
Running a Program............................................................................................29
Conversion to Java2 ..........................................................................................30
Chapter 4. Using the Generator Command................................................31
Starting the J Adapter Class Generator................................................................32
Optional File .....................................................................................................36
Output .............................................................................................................42
Chapter 5. Adapter Class Reference ..........................................................45
Class Configuration............................................................................................46
FJ-JAVA-BASE class ...........................................................................................47
FJ-JAVA-CONTROL class ....................................................................................48
FJ-JAVA-ERROR class.........................................................................................50
Class or Interface Adapter Class .........................................................................51
java-lang-String class.........................................................................................61
Array Adapter Class...........................................................................................65
Numbering Names.............................................................................................69
Chapter 6. Messages ..................................................................................73
Java2cob Command Messages............................................................................74
Messages Output during Generation....................................................................74
NetCOBOL J Adapter Class Generator User's Guide 7
Messages Output during Execution .....................................................................77
Chapter 7. Samples ....................................................................................81
Sample 1 – Using Classes...................................................................................81
Sample 2 – Specifying Method............................................................................83
Appendix A. Message List...........................................................................85
Java2cob Command Messages............................................................................86
Messages Output during Generation....................................................................87
Messages Output during Execution .....................................................................90
Appendix B. Exception Type List................................................................93
Index...........................................................................................................97
8 NetCOBOL J Adapter Class Generator User's Guide
Chapter 1. Outline of J Adapter Class Generator
This chapter explains the function and operating environment of the J adapter class
generator.
10 Chapter 1. Outline of J Adapter Class Generator
What is the J Adapter Class Generator?
Taking advantage of the object-oriented function, Fujitsu NetCOBOL enables
programming using class libraries . The Fujitsu NetCOBOL also provides many useful
foundation classes. Meantime, as Java becomes popular, many Java class libraries
are also provided. However, the class structure varies from language to language
and therefore Java class libraries cannot normally be used from COBOL.
The J adapter class generator provides a framework that enables COBOL to use Java
classes.
The J adapter class generator enables a COBOL program to:
Use a Java class library. •
•
Call a Java application.
•
Use an application program interface (API) provided for Java.
The J adapter class generator enables COBOL to be used for systems that previously
could only have been implemented in Java.
Use of the J adapter class generator is recommended in the following situations:
•
Constructing a COBOL system using Java common parts such as EJB
components.
•
Constructing a COBOL system using whole Java applications.
An outline of the J adapter class generator is given below:
Figure 1.1
Chapter 1. Outline of J Adapter Class Generator 11
The Java class interface must be converted into the COBOL interface for a COBOL
program to use Java classes. The J adapter class generator generates an adapter
class that converts the Java interface into the COBOL interface.
What the J Adapter Class Generator Can Do
Using adapter classes generated by the J adapter class generator enables the
following types of operation for Java.
To COBOL programs, Java objects seem to be COBOL objects. Therefore, Java
objects can be handled the same way as ordinary COBOL objects.
•
Accessing a class variable
Access to a public class variable (static field) declared in a Java class is enabled.
COBOL handles it as a factory property.
•
Invoking a class method
A public class method (static method) declared in a Java class can be invoked.
COBOL handles it as a factory method.
•
Generating an instance object (invoking a constructor)
Invoking a constructor can create a Java instance object. COBOL handles it as a
factory method that returns an object.
Accessing an instance variable
•
Access to a public instance variable (non-static field) of a Java instance object is
enabled. COBOL handles it as an object property.
Invoking an instance method
•
A public instance method (non-static method) of a Java instance object can be
invoked. COBOL handles it as an object method.
•
Receiving an exception
An exception caused when a class method, constructor, or instance method is
invoked can be trapped to perform error processing. COBOL uses the USE
statement to receive an exception object.
What the J Adapter Class Generator Cannot Do
The J adapter class generator cannot perform the following types of operation:
• • Inheriting a Java class
A COBOL class inheriting a Java class cannot be defined. Even if a COBOL class
inherits an adapter class, the Java class function cannot be overwritten.
Passing a COBOL object as a parameter
No COBOL object can be passed as a parameter for invoking a method, nor can
a COBOL object be set for a Java field. Only an adapter object produced by
wrapping a Java object can be passed to Java.
12 Chapter 1. Outline of J Adapter Class Generator
Therefore, the following restrictions apply to COBOL:
- Listener
Java registers a listener object, in which event processing logic is written,
within an object that generates an event. However, since no COBOL object
can be registered in a Java object, COBOL cannot be used to write listeners.
- Collection class
No COBOL object can be registered in a Java collection class. When using
COBOL objects as a collection, use a COBOL collection class.
• • Class having a Japanese name
No class name, field name, and method name can include the Japanese
character set.
Invoking COBOL from Java
No COBOL program can be invoked from Java. A COBOL program invoked from
Java can use no adapter class.
Preparation
The following products are required for the development or execution environment
for using the J adapter class generator.
Fujitsu NetCOBOL or Fujitsu NetCOBOL Runtime System
Fujitsu NetCOBOL is required to develop programs using the J adapter class
generator. Fujitsu NetCOBOL or Fujitsu NetCOBOL Runtime System is required to
execute applications developed by the J adapter class generator.
Java Development Kit or Java Runtime Environment
Java Development Kit (JDK) is provided by Sun Microsystems, Inc. provides the
basic general-purpose class libraries required for program development with Java.
Java 2 SDK (J2SDK) is a software development kit available for creating applications
conforming to Java 2 released by Sun Microsystems, Inc. J2SDK provides basic
general-purpose class libraries required for program development with Java 2.
Java Runtime Environment (JRE) is the JDK runtime environment released by Sun
Microsystems, Inc. It is required to run programs developed with Java.
Java 2 Runtime Environment (J2RE) is the run time environment of applications
conforming Java 2 released by Sun Microsystems, Inc. It is required to run
programs developed with Java 2.
JDK 1.1.8, J2SDK 1.2.2, or a later version is required to develop programs using the
J adapter class generator. JDK 1.1.8, J2SDK 1.2.2, JRE 1.1.8, J2RE 1.2.2, or a later
version is required to run applications developed using the J adapter class generator.
Chapter 2. Adapter Class Generator Framework
This chapter explains the framework of the J adapter class generator.
14 Chapter 2. Adapter Class Generator Framework
Adapter Class
To make Java classes available to COBOL, a mechanism for converting the Java class
interface into the COBOL interface is required. The J adapter class generator works
as an interface converting mechanism to generate adapter classes corresponding to
Java classes. To use a Java class from a COBOL program, the adapter class created
by the generator can be called. The adapter class is written in COBOL and therefore
can be called in the same manner as a COBOL class.
The relationship between the Java class/interface and adapter class is shown below:
Figure 2.1: Java class/interface and adapter class
Adapter Object
At execution time, an adapter class generates the adapter object corresponding to a
Java instance object. The adapter object:
Holds the pointer to the corresponding Java instance object. •
• Calls the corresponding Java method of the corresponding Java instance object
Only the adapter object can be seen from the COBOL program. Every operation on
the adapter object is transmitted to the corresponding Java object. To the COBOL
program, , the adapter object seems as if it were a Java object. The adapter object,
since it works for the Java object, is also called a proxy object. The relationship
between the Java object and adapter object is shown below:
Chapter 2. Adapter Class Generator Framework 15
Figure 2.2. Java object and adapter object
16 Chapter 2. Adapter Class Generator Framework
Chapter 3. Developing Programs
This chapter explains how to develop programs that use Java classes.
18 Chapter 3. Developing Programs
Creating Adapter Classes
This section explains how to generate an adapter class from a Java class.
Investigating the Java Class
First investigate the specifications of the Java class and interface to be used (class
name, package name, usage, and so on) to check whether the J adapter class
generator can handle the class and interface. See "
Generator Can Do
information on which classes and interfaces can be used.
" and "
Generating Adapter Class Source
If the target Java class and interface can be used, generate adapter class source.
Use the java2cob command to generate adapter classes. The java2cob command
reads the class file (extension .class) of the Java class/interface and generates the
corresponding adapter class source.
What the J Adapter Class Generator Cannot Do
What the J Adapter Class
" for
The java2cob command generates adapter classes of not only the class specified by
the option but also every other class/interface required to use the class.
An example of generating adapter class source from the java.util.Date class is shown
below.
Figure 3.1
Note: The class file referenced by the class/interface may not always be available,
depending on the execution environment. For information on how to generate
Chapter 3. Developing Programs 19
adapter classes when the class file is not available, see "
when the class file is not available
."
Generating an adapter class
Building an Adapter Class
Finally, compile and link-edit the generated adapter class source to create an adapter
class library (DLL). Use the COBOL project manager to do so.
Refer to the Fujitsu NetCOBOL User's Guide for information on how to use the
COBOL project manager
Follow the procedure below to build an adapter class:
1. Create a new project using the project manager.
2. Register the target DLL.
3. Create a COBOL source file folder and store the generated adapter class in it.
4. Specify compiler options.
- Specify XXX\REP (XXX is the J adapter class generator install folder) for
REPIN.
- Specify ALPHAL (WORD).
- When creating an adapter class running with Unicode, specify RCS (UCS2).
5. To determine the compilation order, select “Repository File Search” from the
“Edit” menu and then select “All”.
.
6. Create a library folder and store the runtime library F3BIJART.LIB of the J
adapter class generator in it. F3BIJART.LIB is available from the LIB folder of
the install folder.
7. Execute "build."
The following files are generated:
• Adapter class DLL file (required for execution)
• Adapter class LIB file (required for link-edition)
• Adapter class repository file (required for compilation)
Generating an Adapter Class When the Class File is Not
Available
The J adapter class generator references the following class information when
generating an adapter class:
• Super class/interface
• Class/interface specified in the public method, constructor parameter, or return
value
• Class/interface specified in the public variable
20 Chapter 3. Developing Programs
Therefore, an adapter class cannot be generated normally without these class files.
These class files may not be available depending on the environment. In this case,
to create an adapter class normally, dummy class files having these file names must
be prepared.
Prepare a dummy class file as follows:
1. Create a folder corresponding to the package name. For package name
aaa.bbb.ccc, for instance, create a folder with name aaa\bbb\ccc.
2. Create a Java source program satisfying the following. Assign this file the name
"ClassName.java".
package PackageName;
public class ClassName {}
3. Compile the source program with the Java compiler.
c:\> javac FolderName\ClassName.java
4. Enter the java2cob command.
c:\> java2cob PackageName.ClassName
Note: If a class file is referred to, but does not exist when attempting to generate
an adapter class, processing is terminated with message "
found. Generation was interrupted
."
Class information was not
Reducing the Size of Adapter Class
The adapter class source generated by the J adapter class generator may be simply
compiled and linked before it is used.
Since, however, the adapter source class can include class files, which are not used
by the applications, there might be cases where the size of the DLL file of the
adapter class is significantly larger than necessary. In a case like this, the size of the
adapter class can be reduced by the following methods:
• Specifying the constructor/method/field
• Specifying the -om option or the "Option ReduceClass" parameter
Specifying the Constructor/Method/Field
When the constructors, methods, and fields that are used in the application are
known, the number of the adapter classes generated can be reduced by specifying
them.
The J adapter class generator generates only the adapter classes that are required
by the specified constructors/methods/fields.
Refer to -r option, -gc option, -gm option, -gf option and "Class classname/interface-name" parameters for details of the procedure of specifying the
constructor/method/field.
Chapter 3. Developing Programs 21
Example:
When an application uses only the println (Object) method of the java.io.PrintStream
class, specify as follows:
C:\> java2cob -r java.io.PrintStream -gm "println(java.lang.Object)"
Specifying the -om Option or the "Option ReduceClass"
Parameter
Specifying the -om option or the "Option ReduceClass" parameter can reduce the
number of adapter classes generated. To check for parameter validity at method
invocation, the J adapter class generator generates adapter classes corresponding to
individual parameters. Thus many adapter classes are generated for one class.
When the -om option or the "Option ReduceClass" parameter is specified, all objecttype method parameters are mapped to the java-lang-Object class. This function
suppresses the generation of adapter classes corresponding to the method
parameters and thereby reduces the number of adapter classes generated.
Notes:
• When the method of the adapter class generated with the -om option or the
"Option ReduceClass" parameter specified is invoked, BY CONTENT must be
specified as an object reference parameter.
• When the -om option or the "Option ReduceClass" parameter is specified, the
object reference types of method parameters excluding the return value become
java-lang-Object and therefore the original parameter types become uncertain.
Therefore, for a parameter whose object reference type becomes java-langObject, a parameter name is generated according to the following rules so that
the original type information is included in the parameter name.
Pn-ClassName
• P is followed by a parameter serial number (1 to 99).
• The hyphen "-" is followed by an external class name excluding a package name
after conversion into uppercase.
• A parameter name exceeding 30 characters is truncated after the 30th character.
Example:
When the -om option or the "Option ReduceClass" parameter is not specified,
adapter class source java-io-PrintStream.cob of the java.io.PrintStream class
becomes as shown below, and the java-io-OutputStream class is required.
...
REPOSITORY.
CLASS J-OUTPUTSTREAM AS "java-io-OutputStream"
...
LINKAGE SECTION.
01 PARA-1 OBJECT REFERENCE J-OUTPUTSTREAM.
...
When the -om option or the "Option ReduceClass" parameter is specified, the
parameter becomes the java-lang-Object type. Therefore, the java-io-OutputStream
class is not required or generated.
22 Chapter 3. Developing Programs
...
REPOSITORY.
CLASS J-OBJECT AS "java-lang-Object"
...
LINKAGE SECTION.
01 P1-OUTPUTSTREAM OBJECT REFERENCE J-OBJECT.
...
Developing an Application That Uses an Adapter Class
This section explains how to develop a program that uses an adapter class.
Outline
The flow of program processing using the adapter class is as follows:
1. Initialization of the Java VM.
2. In the case of a multithreaded application, connection of the current thread to
the Java VM .
3. Generation of the object.
4. Calling the method.
5. In the case of a multithreaded application, disconnection from the Java VM .
6. Termination of the Java VM.
Also, be careful when performing the following operations:
• Manipulating a variable
• Comparing object references
• Assignment to a subclass
• Mapping java.lang.String into PIC X.
• End control of character string
• Exception processing
Initializing the Java VM
To use an adapter class, the Java virtual machine (VM) must first be initialized . Use
the JVM-INIT method or the JVM-ATTACH method of the FJ-JAVA-CONTROL class to
initialize the Java VM.
A coding sample is shown below:
...
REPOSITORY.
CLASS FJ-JAVA-CONTROL
...
PROCEDURE DIVISION.
...
INVOKE FJ-JAVA-CONTROL "JVM-INIT".
...
Chapter 3. Developing Programs 23
Terminating the Java VM
When an adapter class is no longer used, the Java VM must be terminated. Use the
JVM-TERMINATE method of the FJ-JAVA-CONTROL class to terminate the Java VM.
A coding sample is shown below:
...
REPOSITORY.
CLASS FJ-JAVA-CONTROL
...
PROCEDURE DIVISION.
...
INVOKE FJ-JAVA-CONTROL "JVM-TERMINATE".
...
Developing a Multithread Application
A multithread application using an adapter class must connect the current thread to
the Java virtual machine (VM). When the multithread application is terminated, the
current thread must first be disconnected from the Java VM.
Use the JVM-INIT method or the JVM-ATTACH method of the FJ-JAVA-CONTROL
class to connect the current thread to the Java VM.
To disconnect the current thread from the Java VM, use the JVM-TERMINATE
method or the JVM-DETACH method of the FJ-JAVA-CONTROL class.
A multithread application sample is shown below:
Figure 3.2
Generating an Object
Generate an object by invoking the adapter class factory method corresponding to
the constructor. Generate the factory method with the following name (see
Constructor
"
Create-JavaClassName-nn (nn is 01 to 99)
").
24 Chapter 3. Developing Programs
An example of generating a Date class object is shown below:
...
REPOSITORY.
CLASS J-Date AS "java-util-Date"
...
WORKING-STORAGE SECTION
01 anDate OBJECT REFERENCE J-Date.
...
PROCEDURE DIVISION.
...
INVOKE J-Date "Create-Date-01" RETURNING anDate.
...
Note:
• Since the adapter class name is very long, it is recommended that an alias be
assigned by specifying AS in the REPOSITORY paragraph.
Invoking a Method
Invoke an instance method by invoking the corresponding adapter class object
method. The method name is the same as that of Java. However, if more than one
method is defined with the same name, append a numeric suffix to distinguish them
Class method"
(see "
and
"Instance method
").
An example of invoking the getTime method of the Date class is shown below:
...
REPOSITORY.
CLASS J-Date AS "java-util-Date"
...
WORKING-STORAGE SECTION
01 anDate OBJECT REFERENCE J-Date.
01 currentTime PIC S9(9) COMP-5.
...
PROCEDURE DIVISION.
...
INVOKE anDate "getTime" RETURNING currentTime.
...
Manipulating a Variable
Manipulate a variable through the corresponding adapter class property. The
JF-
property name is a Java field name with the prefix "
field is defined with the same name, append a numeric suffix to distinguish them
Class variable
(see "
" and "
Instance variable
").
". However, if more than one
Chapter 3. Developing Programs 25
An example of referencing the class variable AM_PM_FIELD (static field) of the
DateFormat class is shown below:
...
REPOSITORY.
CLASS J-DateFormat AS "java-text-DateFormat"
...
WORKING-STORAGE SECTION
01 FMT-Type PIC S9(9) COMP-5.
...
PROCEDURE DIVISION.
...
MOVE JF-AM_PM_FIELD OF J-DateFormat TO FMT-Type.
...
Comparing Object References
COBOL uses "=" to check whether multiple object references point to the same
object. To check whether the Java objects pointed to by the adapter objects are the
same, COBOL uses the J-EQUALS method of the adapter class instead of "=". The
adapter class always has the J-EQUALS method.
An example of comparing two Date objects is shown below. The condition is met
when Date-1 and Date-2 point to the same Java object.
...
REPOSITORY.
CLASS J-Date AS "java-util-Date"
...
WORKING-STORAGE SECTION
01 Date-1 OBJECT REFERENCE J-Date.
01 Date-2 OBJECT REFERENCE J-Date.
01 rst PIC 1.
...
PROCEDURE DIVISION.
...
INVOKE Date-1 "J-EQUALS" USING CONTENT Date-2 RETURNING rst.
IF rst = B"1" THEN
Condition met
...
Assignment to a Subclass
COBOL uses AS to assign an object to a subclass. However, it uses the J-NARROW
method instead of AS to assign an adapter object. The adapter class always has the
J-NARROW method.
26 Chapter 3. Developing Programs
An example of assigning an object, which has been referenced with Object class
data, into Data class data is shown below:
...
REPOSITORY.
CLASS J-Object AS "java-lang-Object"
CLASS J-Date AS "java-util-Date"
...
WORKING-STORAGE SECTION
01 anDate OBJECT REFERENCE J-Date.
01 anObject OBJECT REFERENCE J-Object.
...
PROCEDURE DIVISION.
...
INVOKE J-Date "J-NARROW" USING CONTENT anObject RETURNING anDate.
...
Mapping java.lang.String into PIC X
The java.lang.String is mapped into the java-lang-String class in the generation of
the normal adapter class. In this case, creation of the user's application becomes
somewhat complicated because conversion between the String object and the
COBOL data items must be performed using the java-lang-String class method (such
as NEW-STRING-X, GET-STRING-X).
When the adapter class is generated by specifying the -s option or by specifying the
"Option String" parameter, the following items can be handled as alphanumeric items
in the user's applications, since the java.lang.String type is mapped into PIC X ANY
LENGTH:
• Return values of the java.lang.String type in the method
• Argument of the java.lang.String type in the constructor and method
• Fields (class variables and instance variables) of the java.lang.String type
Example: When the -s option and "Option String" parameter are not specified, the
conversion between the String object and the COBOL data items must be performed
in the user's application using the java-lang-String class method (such as NEWSTRING-X and GET-STRING-X).
…
REPOSITORY.
CLASS J-Date AS "java-util-Date"
CLASS J-String AS "java-lang-String"
CLASS J-DateFormat AS "java-text-DateFormat"
…
WORKING-STORAGE SECTION
01 aDateFormat OBJECT REFERENCE J-DateFormat.
01 aDate OBJECT REFERENCE J-Date.
01 dateString OBJECT REFERENCE J-String.
01 dateValue PIC X(30).
…
PROCEDURE DIVISION.
…
MOVE "2000/01/01" & X"00" TO dateValue.
INVOKE J-String "NEW-STRING-X" USING dateValue RETURNING dateString.
INVOKE aDateFormat "parse" USING dateString RETURNING aDate.
…
INVOKE aDate "toString" RETURNING dateString.
INVOKE dateString "GET-STRING-X" RETURNING dateValue.
Chapter 3. Developing Programs 27
…
When the -s option or the "Option String" parameter is specified, the conversion
between the String object and the COBOL data items is not necessary since an
alphanumeric item can be specified as the String type argument and returns a value
directly.
…
REPOSITORY.
CLASS J-Date AS "java-util-Date"
CLASS J-DateFormat AS "java-text-DateFormat"
…WORKING-STORAGE SECTION
01 aDateFormat OBJECT REFERENCE J-DateFormat.
01 aDate OBJECT REFERENCE J-Date.
01 dateValue PIC X(30).
…
PROCEDURE DIVISION.
…
MOVE "2000/01/01" & X"00" TO dateValue.
INVOKE aDateFormat "parse" USING dateValue RETURNING aDate.
…
INVOKE aDate "toString" RETURNING dateValue.
…
Notes:
• The return value of the java.lang.String class constructor is the java.lang.String
class
• When the String object method is used, the creation of the object (calling the
String constructor or calling the NEW-STRING-X method) is necessary.
• To refer/set the java.lang.String type field (class variable or instance variable),
specify its size using -s option or "Option String" parameter.
• When you want to handle the String type NULL object, do not use the -s option
and "Option String" parameter.
End Control of Character String
When passing a character string that is shorter than the data item length to an
ordinary adapter class, the end of string (X”00”) must be set. The following example
shows that "ABC" is copied to alphanumeric item initialValue having length of 50
characters and is passed to the NEW-STRING-X method:
…
REPOSITORY.
CLASS J-String AS "java-lang-String"
…
WORKING-STORAGE SECTION.
01 initialValue PIC X(50).
01 aString OBJECT REFERENCE J-String.
…
PROCEDURE DIVISION.
…
MOVE "ABC" & X"00" TO initialValue.
INVOKE J-String "NEW-STRING-X" USING initialValue RETURNING aString.
28 Chapter 3. Developing Programs
If an adapter class is generated by specifying the -t option or the "Option Terminal"
parameter, the character string that is shorter than the data item length can be
passed to a method without setting the end of string, since the end (X "00") of the
character string is set in the adapter class.
The following example shows that "ABC" is copied to alphanumeric item initialValue
having the length of 50 characters and is passed to the NEW-STRING-X method:
…
REPOSITORY.
CLASS J-String AS "java-lang-String"
…
WORKING-STORAGE SECTION.
01 initialValue PIC X(50).
01 aString OBJECT REFERENCE J-String.
…
PROCEDURE DIVISION.
…
MOVE "ABC" TO initialValue.
INVOKE J-String "NEW-STRING-X" USING initialValue RETURNING aString.
Exception Processing
When an adapter class detects an error during processing, the exception object is
generated. FJ-JAVA-ERROR class is the class of the exception object.
In order to detect an exception generated in the adapter class, using the "exception
object", the "exception handling" needs be described in the declaratives of the
procedure division of the program, using the USE statement. When the method of
the FJ-JAVA-ERROR class is used in the exception handling, the exception message,
exception type and Java exception information can be extracted. For the details of
the exception handling using the USE statement, refer to "Defining Exception
Processes" of the "Fujitsu NetCOBOL User's Guide".
Example of coding of the exception handling is shown as follows:
…
REPOSITORY.
CLASS FJ-JAVA-ERROR
…
WORKING-STORAGE SECTION
01 errMessage PIC X(256).
01 expMessage PIC X(1024).
01 expClass PIC X(256).
01 errCode PIC S9(9) COMP-5.
01 errMessageLen PIC S9(9) COMP-5.
01 expMessageLen PIC S9(9) COMP-5.
01 expClassLen PIC S9(9) COMP-5.
01 rc PIC S9(9) COMP-5.
…
PROCEDURE DIVISION.
DECLARATIVES.
ERR SECTION.
USE AFTER EXCEPTION FJ-JAVA-ERROR.
INVOKE EXCEPTION-OBJECT "GET-CODE" RETURNING errCode.
INVOKE EXCEPTION-OBJECT "GET-MESSAGE"
USING errMessage RETURNING errMessageLen.
INVOKE EXCEPTION-OBJECT "GET-EXCEPTION"
USING expMessage expMessageLen expClass expClassLen
RETURNING rc.
Chapter 3. Developing Programs 29
DISPLAY "Error Code: " errCode.
DISPLAY "Error Message: " errMessage(1:errMessageLen).
IF rc NOT = -1 THEN
DISPLAY "Java Class Name: " expClass(1:expClassLen)
DISPLAY "Java Exception Message: " expMessage(1:expMessageLen)
END-IF.
END DECLARATIVES.
…
Note: When the exception handling is not described in a program, the program
runtime error (JMP0104I-U) occurs due to the occurrence of the exception object.
Constructing a Program
This section explains how to construct a program that uses an adapter class, by
using the COBOL project manager.
The following files generated from the adapter class are required to construct a
program:
• Adapter class LIB file (for linkage)
• Adapter class repository file (for compilation)
Construct a program as follows:
1. Create a new project using the project manager.
2. Register the target executable program (EXE).
3. Create a COBOL source file folder and store the program source in it.
4. Create a library file folder, and store the adapter class LIB file and J adapter
class generator runtime library F3BIJART.LIB in it. F3BIJART.LIB exists in the
LIB folder of the install folder.
5. Specify compiler and link options:
- For REPIN, specify XXX\REP (XXX is the J adapter class generator install
folder) and the folder containing the adapter class repository.
- Specify ALPHAL (WORD) or NOALPHAL.
- Refer to the
6. Execute "
build
Running a Program
The following file generated from the adapter class is required to run a program:
Fujitsu NetCOBOL User's Guide
."
for other options.
• Adapter class DLL file
Before running the program, add the folder containing the adapter class DLL file to
environment variable PATH.
The program can be run in the same manner as any other COBOL application. Refer
Fujitsu NetCOBOL User's Guide
to the
for details.
Note: The Java VM operating environment can be customized by specifying
environment variables (see ”JVM-INIT method (factory method)”).
30 Chapter 3. Developing Programs
Conversion to Java2
When using the resources (execute-form programs (EXE), DLLs, adapter class
source, and program source using adapter classes) created by JDK1.1.x, note the
following:
• Adapter class source and DLLs created by JDK 1.1.x can be used as they are in
the Java2 environment.
• If an adapter class is recreated by Java2, a method name different from one
created by JDK 1.1.x may be generated (see "
the COBOL program using the Java class must be modified. To prevent this
problem, recreate an adapter class with Java2 by using the generation name
management file generated by JDK 1.1.x.
Numbering names
"). In this case,
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