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On occasion, the question comes back about how to evaluate certain conditions in the "JavaScript" job entry in version 3.x of Pentaho Data Integration.
Evaluation
The result of a JavaScript job entry is either true or false. In other words, it needs to end with a boolean expression.
Here are a few possible evaluations to end your script with :
lines_input > 100
or
true
or
parent_job.getVariable("INPUT_DIRECTORY").equals("/tmp");
Variables
Here is how you can evaluate the content of a variable string:
parent_job.getVariable("NR_OF_ROWS") == 1000000
Since we have access to the parent_job object, we can also set variables in the parent job this way:
parent_job.setVariable("NR_OF_ROWS", "1000000");
(Note that the setVariable call can (always?) evaluates to false. Put a "true" after it to avoid having the step evaluate to false and throw an error)
Previous result
When a job entry finishes, the result of the execution will be a Result object exposed as "previous_result" to the JavaScript engine:
| Expression | Alternative | Data type |
Meaning |
|---|---|---|---|
| previous_result.getResult() | |
boolean |
true if the previous job entry was executed successfully, false if there was some error. |
| previous_result.getExitStatus() |
exit_status | int |
exit status of previous shell script job entry |
| previous_result.getEntryNr() |
nr | int |
The entry number is increased every time a job entry is executed. |
| previous_result.getNrErrors() | errors | long |
the number of errors, also available as variable "errors" |
| previous_result.getNrLinesInput() | lines_input | long |
The number of rows read from a file or database |
| previous_result.getNrLinesOutput() | lines_output | long |
The number of rows written to a file or database |
| previous_result.getNrLinesRead() | lines_read | long |
The number of rows read from previous steps |
| previous_result.getNrLinesUpdated() | lines_updated | long |
The number of rows updated in a file or database |
| previous_result.getNrLinesWritten() | lines_written |
long |
The number of rows written to next step |
| previous_result.getNrLinesDeleted() | lines_deleted |
long | The number of deleted rows |
| previous_result.getNrLinesRejected() | lines_rejected | long |
The number of rows rejected and passed to another step via error handling |
| previous_result.getRows() | |
List<RowMetaAndData> | The result rows, see also below. |
| previous_result.isStopped() | boolean |
Flag to signal if the previous previous job entry stopped or not. |
|
| previous_result.getResultFilesList() | List<ResultFile> |
The list of all the files used in the previous job entry (or entries) |
|
| previous_result.getNrFilesRetrieved() | files_retrieved |
int |
The number of files retrieved from FTP, SFTP, etc. |
Platform
We also expose a variable called "is_windows" to help you make platform specific choices
rows
The "rows" variable we expose to JavaScript helps you evaluate the result rows you passed to the next job entry using the "Copy rows to result" step.
Here is an example script on how to use this array:
var firstRow = rows[0]; firstRow.getString("name", "").equals("Foo")
This script will follow the green job hop is the expression evaluates to true. This happens if field "name" contains String "Foo".
Make sure that you specify a step to pick the "lines_input" and other numbers from otherwise the values will remain 0 for the all eternity. Open the transformation file and Do that in the Transformation settings dialog , log tab.
Zokt said so.