Builds a lookup map of values keyed by an expression, storing it as a pipeline attribute for later steps. Each incoming row is evaluated with keyColumn to compute a map key and, if valueColumn is set, with valueColumn to compute the stored value; otherwise the whole row is stored. The resulting map is created and written into the pipeline's attributes under keyAttribute when prepare() runs, so a later step's expression can look up values by key, for example to correlate rows from two different data sources that share a common key. Rows are always passed through unchanged to the next step.

Implements: PipelineStep

Properties

Methods

getFormPath()

Returns: String

Path to the Velocity template used by the pipeline management UI to edit this step's configuration.

getDescription()

Returns: String

Human-readable summary of this step, shown to administrators managing the pipeline: that it builds a lookup map keyed by an expression and stores it as a pipeline attribute.

getKeyAttribute()

Returns: String

Name of the pipeline attribute that the computed map is stored under.

getKeyColumn()

Returns: Column

Column expression evaluated against each incoming row to compute the map key it is stored under.

getValueColumn()

Returns: Column

Column expression evaluated against each incoming row to compute the value stored for it; when unset, the whole row is stored instead.

getNextStep()

Returns: PipelineStep

The step that every row is passed to after being added to the map.