xJCL elements

Jobs are described using a job control language. Batch jobs use an XML-based job control language. The job description identifies which application to run, its inputs, and outputs.

Jobs are expressed using an Extensible Markup Language XML dialect called XML xJCL Job Control Language. See the xJCL provided with the Sample applications, the xJCL table and xJCL XSD schema document for more information about xJCL. The xJCL definition of a job is not part of the batch application, but is constructed separately.

The following table summarizes the xJCL elements:

Table 1. xJCL elements
Element	Sub-element	Attributes	Description
job	not-applicable	not-applicable	Scopes the description of a batch job.
not-applicable	not-applicable	name	Name of the job. This name must match the name of the batch application.
not-applicable	step-scheduling-criteria	See step-scheduling-criteria element	not-applicable
not-applicable	checkpoint-algorithm	See checkpoint-algorithm element	not-applicable
not-applicable	job-step	See job-step element	not-applicable
job-step	not-applicable	not-applicable	not-applicable
not-applicable	not-applicable	name	Name of the step. This information is returned on operational commands.
not-applicable	step-scheduling	See step-scheduling element	Allows for conditional logic based on return codes of steps that determine if the batch step should be invoked or not
not-applicable	checkpoint-algorithm-ref	See checkpoint-algorithm-ref element	Specifies the checkpoint algorithm to use for the batch job step.
not-applicable	classname	not-applicable	Fully-qualified name of class that implements the compute intensive job.
not-applicable	props	See props element	Name-value properties to pass to the step
not-applicable	batch-data-streams	See batch-data-streams element	A sequence of `bds` elements. Each `bds` is the configuration information necessary to create a batch data stream.
prop	not-applicable	not-applicable	Single instance of a name value pair, that serves as a property.
not-applicable	not-applicable	name	Name of the property.
not-applicable	not-applicable	value	Value of the property.
props	not-applicable	not-applicable	Series of `prop` elements that are used to pass name value pair properties to steps, `bds`, checkpoint algorithms and results algorithms.
not-applicable	prop	See prop element	not-applicable
bds	not-applicable	not-applicable	Single instance of a batch data stream implementation that is made available to the batch job to use.
not-applicable	logical-name	not-applicable	A string that is embedded in batch step that the batch step uses to ask the batch runtime environment for a specific batch data stream instance.
not-applicable	impl-class	not-applicable	Fully qualified class name of the batch data stream implementation class.
not-applicable	props	See Props elements	List of properties that are passed to the batch data stream implementation class.
batch-data-streams	not-applicable	not-applicable	Series of `bds` elements
not-applicable	bds	see bds element	not-applicable
step-scheduling	not-applicable	not-applicable	Can be applied to job steps to create return code-based conditional flows for a batch job. Can compare values of return codes defined for this batch job to decide whether a step is invoked or not while processing a batch job. The values of return codes are compared using the return code-expression element.
not-applicable	returncode- expression	see returncode-expression	Returncode- expression for evaluation.
not-applicable	not-applicable	condition	If there is more than one returncode-expression element in the step-scheduling element, then conditional operators can be applied to them. Conditional operators supported are: AND, OR.
returncode-expression	not-applicable	not-applicable	Used for step scheduling tags to decide if a batch job step is run based on return codes of other job steps.
not-applicable	not-applicable	step	Name of step whose return code is to be compared in this expression.
not-applicable	not-applicable	operator	Operator to use for the return code expression; the supported operators are: eq equals, lt less than, gt greater than, le less than or equal to, ge greater than or equal to.
not-applicable	not-applicable	value	The value with which to compare the return code.
step-scheduling-criteria	not-applicable	not-applicable	Describes the sequence in which the job steps are processed. Currently sequential scheduling is supported, and steps get invoked in the order in which they are displayed in xJCL.
not-applicable	scheduling-mode	not-applicable	Sequence in which to invoke steps: only possible value is sequential
checkpoint-algorithm	not-applicable	not-applicable	Declares a checkpoint algorithm that can be used for a batch job step.
not-applicable	not-applicable	name	Name of algorithm.
not-applicable	classname	not-applicable	Class that implements this algorithm.
not-applicable	props	see props element	Sequence of `props` elements for the checkpoint algorithm.
checkpoint-algorithm-ref	not-applicable	not-applicable	Reference to a checkpoint algorithm element.
not-applicable	not-applicable	name	Name of checkpoint algorithm to which you are referring.
not-applicable	props	see props element	Sequence of prop elements for the checkpoint algorithm.
++ The xJCL element substitution-props is discussed in the following section.