Capturing messages from Jar

In November I described how it was possible to zip files in the IFS using the Jar java command. John King emailed me to inform me that there is a way to monitor messages coming from QShell by using the environment variables QIBM_QSH_CMD_OUTPUT and QIBM_QSH_CMD_ESCAPE_MSG.

I am going to use the same example I used before. I have a file testfile.csv that I want to zip using the Jar. And then I will do the opposite and unzip the zipped file using the Jar. All of these files will be in my folder in the IFS called MyFolder.

To be able to make the QShell monitor-able I need to define the two environmental variables.

08 RMVENVVAR ENVVAR(QIBM_QSH_CMD_OUTPUT) 09 MONMSG MSGID(CPFA981) 10 RMVENVVAR ENVVAR(QIBM_QSH_CMD_ESCAPE_MSG) 11 MONMSG MSGID(CPFA981) 12 ADDENVVAR ENVVAR(QIBM_QSH_CMD_OUTPUT) VALUE(NONE) 13 ADDENVVAR ENVVAR(QIBM_QSH_CMD_ESCAPE_MSG) VALUE(Y)

On lines 8 and 10 I remove any existing values/definitions for environmental values. If they have not been defined in this job then the MONMSG, lines 9 and 11, will stop the program from erroring out.

Then I add the environmental values on lines 12 and 13.

I have passed the value of ‘NONE’ to QIBM_QSH_CMD_OUTPUT, line 12, as I do not want the STDOUT output or to output to an outfile, ‘FILE’.

I have passed the value of ‘Y’ to QIBM_QSH_CMD_ESCAPE_MSG, line 13, to ensure that the QSH0005 message is sent as an escape message if the exit status was successful and QSH0006 or QSH0007 is it was not.

Now for the rest of the program:

14 DEL OBJLNK('MyFolder/zipfile.zip') 15 MONMSG MSGID(CPFA0A9) 16 CHGVAR VAR(&CMD) VALUE('Jar cfM MyFolder/zipfile.zip + MyFolder/testfile.csv') 17 CALLSUBR SUBR(SUBR_1) 18 DEL OBJLNK('MyFolder/testfile.csv') 19 MONMSG MSGID(CPFA0A9) 20 CHGVAR VAR(&CMD) VALUE('Jar xf MyFolder/zipfile.zip + MyFolder/testfile.csv') 21 CALLSUBR SUBR(SUBR_1) /*==============================================================*/ 22 SUBR SUBR(SUBR_1) 23 CHGVAR VAR(&ERROR) VALUE('0') 24 STRQSH CMD(&CMD) 25 MONMSG MSGID(QSH0005 QSH0006 QSH0007) + EXEC(CHGVAR VAR(&ERROR) VALUE('1')) 26 IF COND(&ERROR = '0') THEN(RTNSUBR) 27 RCVMSG MSGTYPE(*LAST) RMV(*YES) MSGDTA(&MSGDTA) + MSGID(&MSGID) 28 SELECT /* QSH0005 - ended normally */ 29 WHEN COND(&MSGID = 'QSH0005') THEN(DO) 30 CHGVAR VAR(&RESULT) VALUE(%SST(&MSGDTA 1 4)) 31 CHGVAR VAR(&STATUS) VALUE(%BIN(&RESULT)) ENDDO /* QSH0006 - ended when it received a signal */ 32 WHEN COND(&MSGID = 'QSH0006') THEN(DO) 33 CHGVAR VAR(&RESULT) VALUE(%SST(&MSGDTA 1 4)) 34 CHGVAR VAR(&STATUS) VALUE(%BIN(&RESULT)) 35 ENDDO /* QSH0007 - ended due to exception (pgm crash) */ 36 WHEN COND(&MSGID = 'QSH0007') THEN(DO) 37 CHGVAR VAR(&STATUS) VALUE(-1) 38 ENDDO 39 ENDSELECT 40 IF COND(&STATUS *NE 0) THEN(+ 41 SNDPGMMSG MSGID(CPF9897) MSGF(QCPFMSG) + MSGDTA('Call to QSHELL ''' || &CMD |< + ''' encountered errors')) 42 ENDSUBR /*==============================================================*/ 43 ENDPGM

On line 14 I delete the zip file.

I move the Jar I want to execute to a variable &CMD on line 15.

I then call the subroutine, line 17, to perform the Jar and perform error checking. Click on this link to learn more about subroutines in CL.

I execute the Jar command, on line 24, in the field &CMD. As I have define the environmental variables I can monitor for the QShell error codes QSH0005, QSH0006, and QSH0007, on line 25.

On line 27 I use the RCVMSG command to receive/retrieve the details of the previous message issued in this job.

Rather than use nested If statements I have used a Select group in lines 28–39. To learn about the Select group in CL read Select in CL.

Depending on the message id I get the status of the message received/retrieved on lines 30-31, 33-34, or in the case of QSH0007 I hard code in a negative value. This status is then used to condition a message, on line 41, to tell the user that the Jar encountered errors.

On lines 18 – 21 I take the zip file and extract the file from it.

Below is the program in its entirety:

01 PGM 02 DCL VAR(&CMD) TYPE(*CHAR) LEN(3000) 03 DCL VAR(&ERROR) TYPE(*LGL) 04 DCL VAR(&MSGDTA) TYPE(*CHAR) LEN(256) 05 DCL VAR(&MSGID) TYPE(*CHAR) LEN(7) 06 DCL VAR(&RESULT) TYPE(*CHAR) LEN(4) 07 DCL VAR(&STATUS) TYPE(*DEC) LEN(10 0) 08 RMVENVVAR ENVVAR(QIBM_QSH_CMD_OUTPUT) 09 MONMSG MSGID(CPFA981) 10 RMVENVVAR ENVVAR(QIBM_QSH_CMD_ESCAPE_MSG) 11 MONMSG MSGID(CPFA981) 12 ADDENVVAR ENVVAR(QIBM_QSH_CMD_OUTPUT) VALUE(NONE) 13 ADDENVVAR ENVVAR(QIBM_QSH_CMD_ESCAPE_MSG) VALUE(Y) 14 DEL OBJLNK('MyFolder/zipfile.zip') 15 MONMSG MSGID(CPFA0A9) 16 CHGVAR VAR(&CMD) VALUE('Jar cfM MyFolder/zipfile.zip + MyFolder/testfile.csv') 17 CALLSUBR SUBR(SUBR_1) 18 DEL OBJLNK('MyFolder/testfile.csv') 19 MONMSG MSGID(CPFA0A9) 20 CHGVAR VAR(&CMD) VALUE('Jar xf MyFolder/zipfile.zip + MyFolder/testfile.csv') 21 CALLSUBR SUBR(SUBR_1) /*==============================================================*/ 22 SUBR SUBR(SUBR_1) 23 CHGVAR VAR(&ERROR) VALUE('0') 24 STRQSH CMD(&CMD) 25 MONMSG MSGID(QSH0005 QSH0006 QSH0007) + EXEC(CHGVAR VAR(&ERROR) VALUE('1')) 26 IF COND(&ERROR = '0') THEN(RTNSUBR) 27 RCVMSG MSGTYPE(*LAST) RMV(*YES) MSGDTA(&MSGDTA) + MSGID(&MSGID) 28 SELECT /* QSH0005 - ended normally */ 29 WHEN COND(&MSGID = 'QSH0005') THEN(DO) 30 CHGVAR VAR(&RESULT) VALUE(%SST(&MSGDTA 1 4)) 31 CHGVAR VAR(&STATUS) VALUE(%BIN(&RESULT)) ENDDO /* QSH0006 - ended when it received a signal */ 32 WHEN COND(&MSGID = 'QSH0006') THEN(DO) 33 CHGVAR VAR(&RESULT) VALUE(%SST(&MSGDTA 1 4)) 34 CHGVAR VAR(&STATUS) VALUE(%BIN(&RESULT)) 35 ENDDO /* QSH0007 - ended due to exception (pgm crash) */ 36 WHEN COND(&MSGID = 'QSH0007') THEN(DO) 37 CHGVAR VAR(&STATUS) VALUE(-1) 38 ENDDO 39 ENDSELECT 40 IF COND(&STATUS *NE 0) THEN(+ 41 SNDPGMMSG MSGID(CPF9897) MSGF(QCPFMSG) + MSGDTA('Call to QSHELL ''' || &CMD |< + ''' encountered errors')) 42 ENDSUBR /*==============================================================*/ 43 ENDPGM

You can learn more about this from the IBM website:

• Running Qshell commands from CL
• Qshell variables
• RMVENVVAR command
• ADDENVVAR command
• RCVMSG command

 

This article was written for IBM i 7.1, and it should work with earlier releases too.