topic Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null) in Talend Studio

tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Thu, 29 Sep 2022 10:04:57 GMT

Hi all!

I have been trying to trim an entry in a table but I keep getting the following error:

Cannot invoke "String.substring(int,int)" because "row.A" is null

The way I did it:

In tmap I tried to check first if the entry is empty and then do the trimming like the following

row.A == null ? row.A : (row.A.length() >10 ? StringHandling.LEFT(row.A,4):row.A)

It is not working. Any suggestions from your side?

Thank you!

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Anonymous — Thu, 29 Sep 2022 12:58:51 GMT

What do you get when you run your code where you check for null?

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Thu, 29 Sep 2022 13:01:14 GMT

I only get the error message as written above.

I thought I am checking für null by

row.A == null ? row.A : (row.A.length() >10 ? StringHandling.LEFT(row.A,4):row.A)

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Anonymous — Thu, 29 Sep 2022 13:10:16 GMT

That code should work. Can you post the exact error message you get? This could be related to another column.

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Thu, 29 Sep 2022 14:16:17 GMT

Exception in component tMap_3 (Trim)

java.lang.NullPointerException: Cannot invoke "String.length()" because "row.A" is null

at project_1.trim_0_1.Trim.tFileInputExcel_3Process(Trim.java:1967)

at project_1.trim_0_1.Trim.runJobInTOS(Trim.java:2555)

at project_1.trim_0_1.Trim.main(Trim.java:2393)

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Anonymous — Thu, 29 Sep 2022 14:32:44 GMT

Can you show me a screenshot of your tMap configuration please? I'll need to see every output expression.

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Fri, 30 Sep 2022 08:50:17 GMT

here is the screenshot for this error message ( column A type: string)

Exception in component tMap_3 (test_TrimSTring)

java.lang.NullPointerException: Cannot invoke "String.substring(int, int)" because "row3.A" is null

at project_1.test_trimstring_0_1.test_TrimSTring.tFileInputExcel_3Process(test_TrimSTring.java:1588)

at project_1.test_trimstring_0_1.test_TrimSTring.runJobInTOS(test_TrimSTring.java:2042)

at project_1.test_trimstring_0_1.test_TrimSTring.main(test_TrimSTring.java:1880)

I also tried

(row3.A== null) || ("".equals(row3.A)) || row3.A.isEmpty() ? row3.newColumn1.length()>7 ? StringHandling.LEFT(row3.A,7): row3.A : row3.A

and with brackets

((row3.A== null) || ("".equals(row3.A)) || row3.A.isEmpty() )? (row3.newColumn1.length()>7 ? StringHandling.LEFT(row3.A,7): row3.A 😞 row3.A

Error message:

Exception in component tMap_3 (test_TrimSTring)

java.lang.NullPointerException: Cannot invoke "String.substring(int, int)" because "row3.A" is null

at project_1.test_trimstring_0_1.test_TrimSTring.tFileInputExcel_3Process(test_TrimSTring.java:1588)

at project_1.test_trimstring_0_1.test_TrimSTring.runJobInTOS(test_TrimSTring.java:2042)

at project_1.test_trimstring_0_1.test_TrimSTring.main(test_TrimSTring.java:1880)

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Anonymous — Fri, 30 Sep 2022 09:37:33 GMT

You have at least 2 other tMap Var expressions using the column row3.A without a check for null. I believe that is your problem here.

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Fri, 30 Sep 2022 18:34:17 GMT

thanks for the tipp.

It still doesnt work properly: It works for row3.newColumn but eg not for row3.newColumn4 or row3.newColumn7. I have no idea why.

in tmap:

((row3.newColumn1== null) || ("".equals(row3.newColumn1 )) || row3.newColumn1.isEmpty()) ? (row3.newColumn1.length()>7 ? StringHandling.LEFT(row3.newColumn1,7): row3.newColumn1) : row3.newColumn1

Error:

Exception in component tMap_3 (B_TrimSTring)

java.lang.NullPointerException: Cannot invoke "String.length()" because "row3.newColumn1" is null)

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Anonymous — Fri, 30 Sep 2022 18:45:13 GMT

This is caused by the logic here.....

((row3.newColumn1== null) || ("".equals(row3.newColumn1 )) || row3.newColumn1.isEmpty()) ? (row3.newColumn1.length()>7 ? StringHandling.LEFT(row3.newColumn1,7): row3.newColumn1) : row3.newColumn1

This is saying....

IF row3.newColumn1 is null OR row3.newColumn1 is an empty String OR row3.newColumn1 is empty THEN

IF row3.newColumn1 is longer than 7 characters THEN .... do the rest.

If row3.newColumn1 is null you are allowing the code to attempt to use the length() method on a null object. This is not possible.

I think you need.....

((row3.newColumn1== null) || ("".equals(row3.newColumn1 )) || row3.newColumn1.isEmpty()) ? row3.newColumn1 : row3.newColumn1.length()>7 ? StringHandling.LEFT(row3.newColumn1,7): row3.newColumn1

Re: tmap trimming an entry - problem when entry is empty (cannot invoke "String.substring(int,int)" because "row.A" is null)

Moro — Fri, 30 Sep 2022 19:11:06 GMT

So true! Thank you very much! It works!