JavaScript (job entry)
Description
Use the JavaScript job entry to calculate a boolean expression. The result can be used to determine which step will be executed next. You can use functions, procedure calls, ANDs, ampersands, ORs, EQUALs, etc. The Javascript job entry evaluates and returns a true or false.
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");
The following variables are available for the expression:
Note: Make sure that you specify a step to pick the "lines_input" and other numbers from. Otherwise the values will remain 0. Open the transformation file and do that in the Transformation settings dialog, log tab.
Variable |
Description |
---|---|
errors |
Number of errors in the previous job entry (long) |
lines_input |
Number of rows read from database or file (long) |
lines_output |
Number of rows written to database or file (long) |
lines_updated |
Number of rows updated in a database table (long) |
lines_read |
number of rows read from a previous transformation step (long) |
lines_written |
Number of rows written to a next transformation step (long) |
files_retrieved |
Number of files retrieved from an FTP server (long) |
exit_status |
The exit status of a shell script (integer) |
nr (integer) |
The job entry number of the previous job entry (long); increments at every next job entry |
is_windows |
use if Pentaho Data Integration runs on Windows (boolean) |
parent_job |
The parent job of the current job entry (org.pentaho.di.job.Job class) |
_entry_ |
The current job entry (org.pentaho.di.job.entries.JobEntryEval class) |
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 evaluates to false. Put a "true" after it to avoid having the step evaluate to false and throw an error.
For example you can do something like the following to manipulate variables within this job entry:
useDate = parent_job.getVariable("use_date").equals("1"); if (useDate == 0) { //We get to use native java classes as this is using Rhino mocks??? date = new java.util.Date(); date.setDate(date.getDate()-1); //Go back 1 full day dateFormat = new java.text.SimpleDateFormat("yyyyMMdd"); newDateStr = dateFormat.format(date); parent_job.setVariable("start_date", newDateStr); } true;
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. |
previous_result.getLogText() |
|
String |
The log text of the execution of the previous job entry and its children. |
previous_result.getLogChannelId() |
|
String |
The ID of the log channel of the previous job entry. You can use this to look up information on the execution lineage in the log channel log table. |
|
is_windows |
Boolean |
True if the job runs on Windows variants, false if this is not the case. |
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".