问题:

I'm new to Talend and need an example job to implement tLoop. I want to run a job 10 times if it fails. I've looked at the documents, but I can't seem to figure this out.

回答1:

This answer has 2 sections

Creating a loop with tJava
Retying a failed connection to a data source 5 times (with adding tJavaFlex)

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SECTION 1 : Creating a loop with tJava

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I just write a tJava component and then iterate to false. Like this

Step 1: create a context variable

Step 2: write some java code in tJava (tJava1)

// setting loop flag context.continueLooping = true; //log.info("Starting job...");

then connect On Component Ok

Step 3: Create the tLoop

in the loop condition put your context context.continueLooping which should be true by the first iteration.

then iterate

to the next tJava (tJava2)

if ( ((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) == 1) {    // code  } else if(((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) == 2)  {    // code  } else if (((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) == 3) {    // code  } else if (((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) == 4) {    // code  } else if (((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) == 5) {    // code     context.continueLooping = false;   // log.info("DONE"); }  else  {    context.continueLooping = false;   // log.error("out of bounds...");  }

this tJava runs different code for each iteration till it reaches 5 I use this area to count stuff and load value to other contexts and more.

Then it runs the nest part n times till the context value is set to false.

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SECTION 2 : TO Retry Failed Connections

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if you need to retry a DB connection.

add a tJavaFlex between tLoop1 and tJava2 like so

and add the following code in the 3 sections Start:

// start part of your Java code try{

Main:

// here is the main part of the component, // a piece of code executed in the row // loop if ( ((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) > 1) { Thread.sleep(10000); }

End:

// end of the component, outside/closing the loop }catch (Exception e) {  if ( ((Integer)globalMap.get("tLoop_1_CURRENT_ITERATION")) > 5) { context.continueLooping = false; } else { System.out.println("Connection failed. Retrying...next"); }   }

and add On Component Ok tJava with the code to stop looping on the success (tJava3)

context.continueLooping = false;

转载请标明出处:How to implement tLoop in Talend?

文章来源: How to implement tLoop in Talend?

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