CICS-Run Java application-(1) Run a simple sample app
Introduction
COBOL, PL / I, and Asembler are often used as application development languages for CICS Transaction Server for z / OS, but Java has also been supported for a long time. This means that you can write CICS applications in Java. A Java Class Library (JCICS) equivalent to the EXEC CICS commands is provided, so you can use Java methods to perform operations such as EXEC CICS LINK or EXEC CICS START. Here, we will try to actually run the CICS-Java application sample (OSGi compliant).
- By the way, you can also run Java EE apps on CICS. Reference: Running Java EE application on CICS
Related article
CICS-Run Java application-(1) Run simple sample application CICS-Run Java application-(2) Build management by Maven CICS-Run Java application-(3) Build management with Gradle CICS-Run Java application-(4) Spring Boot application
Environmental information
Development environment Windows10 CICS Explorer V5.6(Beta)
** Execution environment ** z/OS V2.4 CICS Transaction Server for z/OS V5.6(Beta)
About CICS Java support
Here's a summary of CICS's Java support. CICS supports OSGi-compliant Java applications. To run a CICS application implemented in Java, the following procedure is required.
** Runtime preparation ** In order to execute a Java application, create a resource definition called JVMSERVER in the target CICS region and prepare a Java execution environment.
development of Development work is done with the free Eclipse-based tool "CICS Explorer". Create a Java app that imports the JCICS library and package it in the form of an OSGi bundle (like an extension of a jar). (Reference: OSGI Overview) At this time, the first logic to be recognized as a CICS program needs to be implemented in the main function. Package some OSGi Bundles in units called "CICS bundles".
- Liberty can also be run on CICS, and Java EE apps can also be run on Liberty on CICS. In that case, Java EE apps are packaged in units of WAR and EAR, but the idea of packaging them in units called "CICS bundles" is the same.
** Deploy ** Transfer the CICS bundle onto USS on z / OS in the execution environment. Create a BUNDLE definition in the resource definition of the CICS region to recognize the CICS bundle (Java app) transferred on the USS. Create a PROGRAM definition in the resource definition of the CICS region and register the Java class contained in BUNDLE as a CICS program.
The relationship between each CICS resource definition and the entity is as follows.
Advance preparation
Development environment
Download and set up an Eclipse-based tool called CICS Explorer, referring to the following areas. Reference: Downloading and starting CICS Explorer
- This tool is a tool that CICS users can use free of charge.
As a host connection definition, configure an FTP connection for the z / OS on which the target CICS runs.
Execution environment
Prepare a CICS region to run the sample. For now, we'll use a region named ** CT56B4A1 **. Add a resource called JVMServer to run Java applications.
JVM profile
Prepare the JVM profile on USS. (Properties for the JVMServer are effectively specified in a file on this USS. The JVMSERVER resource definition points to the filename of this JVM profile.) A sample is provided, so copy it and use it.
Create a directory called /var/cicsts/cicsts56/CT56B4A1/JVMProfiles and copy /usr/lpp/cicsts/cicsts56/JVMProfiles/DFHOSGI.jvmprofile (sample definition for OSGi located under the CICS installation directory) to it. To do. Customize as appropriate for your environment.
DFHOSGI.jvmprofile excerpt
JAVA_HOME=/usr/lpp/java/J8.0_64/
WORK_DIR=/var/cicsts/cicsts56/CT56B4A1/work
-Xms32M
-Xmx256M
-Xmso1M
-Xgcpolicy:gencon
-Xscmx256M
-Xshareclasses:name=cicsts%g,groupAccess,nonfatal
-Xtune:virtualized
-Dcom.ibm.tools.attach.enable=no
_BPXK_DISABLE_SHLIB=YES
SIT
Specify the directory where the above properties file is located in the SIT parameter "JVMPROFILEDIR".
JVMPROFILEDIR=/var/cicsts/cicsts56/CT56B4A1/JVMProfiles
Restart the region for the changes to take effect.
JVM Server definition
Prepare the JVMSERVER resource definition. Copy the JVMSERVER definition "DFHJVMS" in the product-provided group called DFH $ OSGI to an appropriate group and install it.
OBJECT CHARACTERISTICS CICS RELEASE = 0730
CEDA View JVmserver( DFHJVMS )
JVmserver : DFHJVMS
Group : TAG$OSGI
DEScription : CICS JVM server to run OSGi samples
Status : Enabled Enabled | Disabled
Jvmprofile : DFHOSGI (Mixed Case)
Lerunopts : DFHAXRO
Threadlimit : 015 1-256
DEFINITION SIGNATURE
DEFinetime : 06/02/20 17:28:17
CHANGETime : 06/02/20 17:28:17
CHANGEUsrid : CICSUSER
CHANGEAGEnt : CSDApi CSDApi | CSDBatch
CHANGEAGRel : 0730
- Jvmprofile: DFHOSGI, which means that the file DFHOSGI.jvmprofile under the directory specified in the JVMPROFILEDIR of SIT is used as the JVM properties file.
It is OK if it is enabled by looking at CEMT I JVMSERVER.
I JVMS
STATUS: RESULTS - OVERTYPE TO MODIFY
Jvm(DFHJVMS ) Ena Prf(DFHOSGI ) Ler(DFHAXRO )
Threadc(000) Threadl( 015 ) Cur(9965280)
bundle File placement directory
Create a directory on USS to place the bundle file.
Here, we will create a directory called / var / cicsts / cicsts56 / CT56B4A1 / bundles /.
Sample application operation check
Reference: Java samples: JCICS examples
Creating a sample project
Select Window-Settings from the CICS Explorer menu to open the settings window.
Plugin Development-Select your target platform and click Add.
Select the target CICS version in the template. Here, select CICS TS V5.6.
Check and apply the added CICS TS 5.6.
In the Java perspective, select File-New-Other from the menu
Select CICS Bundle OSGi Sample
Continue as it is
End as it is
A sample project is created.
Check the contents of the sample
There are several sample apps provided for this project, but let's take a look at the simplest Hello World source. (examples.hello.HelloCICSWorld.java included in the com.ibm.cics.server.examples.hello project (OSGi bundle))
HelloCICSWorld.java
package examples.hello;
import com.ibm.cics.server.CommAreaHolder;
import com.ibm.cics.server.Task;
public class HelloCICSWorld
{
public static void main(CommAreaHolder CAH)
{
Task t = Task.getTask();
if ( t == null )
System.err.println("HelloCICSWorld example: Can't get Task");
else
t.out.println("Hello from a Java CICS application");
}
}
JCICS com.ibm.cics.server.Task is used. Task.out means PrintWriter for terminal output, so it is the logic to send a simple character string to the terminal. Reference: [Javadoc --Task](https://www.ibm.com/support/knowledgecenter/SSGMCP_5.6.0/reference-javadocs/jcics-javadoc/com/ibm/cics/server/Task.html?view=embed# out)
Let's check META-INF / MANIFEST.MF of the same project.
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Hello Plug-in
Bundle-SymbolicName: com.ibm.cics.server.examples.hello
Bundle-Version: 1.0.0
Bundle-RequiredExecutionEnvironment: J2SE-1.4,
J2SE-1.5,
JavaSE-1.6
Import-Package: com.ibm.cics.server;version="[1.0.0,2.0.0)"
CICS-MainClass: examples.hello.HelloCICSWorld, examples.hello.HelloWorld
The CICS-MainClass specification specifies a class that has a main method. The main method of the class specified here can be recognized as a CICS program (it can be linked with the program definition).
Check out the CICS bundle project called com.ibm.cics.server.examples.bundle.
If you open META-INF / cics.xml in the CICS Bundle Manifest Editor, you can see that it contains the OSGi bundle above.
Open com.ibm.cics.server.examples.hello.osgibundle.
Check the value of jvmserver specified here. You must specify the name of the JVMSERVER definition to run here. Modify it according to the name of the JVMSERVER definition created in the preparation. If you copy the sample definition with the same name, it will be DFHJVMS, so you do not need to change it.
Deploy your application to CICS
Deploy to CICS in units of "CICS bundles".
Right-click the com.ibm.cics.server.examples.bundle project and click Export Bundle Project to z / OS UNIX File System.
Select Export to a specific location in the file system and Next
Specify the directory for arranging the bundle file created earlier and exit
Check the message
The bundle file has been placed on USS.
Copy each resource in the CICS-supplied DFH $ OSGI group to the appropriate group.
Customize the BUNDLE definition "DFH $ OSGB" and set the BUNDLEDIR value to the directory where you placed the bundle files above (/var/cicsts/cicsts56/CT56B4A1/bundles/com.ibm.cics.server.examples.bundle_1. Replace with 0.0).
OVERTYPE TO MODIFY CICS RELEASE = 0730
CEDA ALter Bundle( DFH$OSGB )
Bundle : DFH$OSGB
Group : TAG$OSGI
DEScription ==> CICS bundle containing OSGi sample bundles
Status ==> Enabled Enabled | Disabled
BUndledir ==> /var/cicsts/cicsts56/CT56B4A1/bundles/com.ibm.cics.server.
(Mixed Case) ==> examples.bundle_1.0.0
==>
==>
==>
BAsescope ==>
(Mixed Case) ==>
==>
==>
==>
DEFINITION SIGNATURE
DEFinetime : 06/02/20 18:27:37
CHANGETime : 06/02/20 18:27:37
Install it and make sure it is enabled.
I BUNDLE
STATUS: RESULTS - OVERTYPE TO MODIFY
Bun(DFH$OSGB) Ena Par(00003) Tar(00003)
Enabledc(00003) Bundlei(com.ibm.cics.server.exampl)
By the way, if you check the resource definition with CICS Explorer, you can check not only the BUNDLE definition but also the BUNDLE PARTS included in BUNDLE.
Sample execution
This time we will run the Hello World sample, so we will install additional resource definitions related to this sample. Reference: Running the Hello World example
The program definition "DFJ $ JHE2" and the transaction definition "JHE2". The actual Java program has already been installed as BUNDLE. Both are provided in DFH $ OSGI, so copy them and install them as they are. By the way, if you take a look at the definition of DFH $ JHE2,
OBJECT CHARACTERISTICS CICS RELEASE = 0730
CEDA View PROGram( DFJ$JHE2 )
PROGram : DFJ$JHE2
Group : TAG$OSGI
DEScription : OSGi Hello CICS world sample program
Language : CObol | Assembler | Le370 | C | Pli
RELoad : No No | Yes
RESident : No No | Yes
USAge : Normal Normal | Transient
USElpacopy : No No | Yes
Status : Enabled Enabled | Disabled
RSl : 00 0-24 | Public
CEdf : Yes Yes | No
DAtalocation : Any Below | Any
EXECKey : Cics User | Cics
COncurrency : Required Quasirent | Threadsafe | Required
Api : Cicsapi Cicsapi | Openapi
REMOTE ATTRIBUTES
DYnamic : No No | Yes
REMOTESystem :
REMOTEName :
Transid :
EXECUtionset : Fullapi Fullapi | Dplsubset
JVM ATTRIBUTES
JVM : Yes No | Yes
JVMClass : examples.hello.HelloCICSWorld
(Mixed Case) :
:
:
:
JVMServer : DFHJVMS
JVMProfile : (Mixed Case)
JAVA PROGRAM OBJECT ATTRIBUTES
Hotpool : No No | Yes
...
Like this, JVM: Yes, JVMClass: examples.hello.HelloCICSWorld, JVMServer: DFHJVMS are specified (classes installed by BUNDLE PARTS). * If the JVM Server name created in advance is different, please correct it accordingly.
Now that the resources are in place, let's run it.
Execute a JHE2 transaction from a CICS terminal.
The string output from the Java program Hello from a Java CICS application is displayed!
This confirms that Java worked as a CICS program.
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