public class SelectComponent extends DelegatingComponent
|Modifier and Type||Class and Description|
Interface used to determine whether a tuple satisfies all of the constraints applied to the SELECT node.
|Constructor and Description|
Create a SELECT processing component that pass those tuples that satisfy the supplied constraint.
|Modifier and Type||Method and Description|
Execute this stage of processing and return the resulting tuples that each conform to the
createDynamicOperation, createSortComparator, emptyTuples, getColumns, getContext, getLocationIndexes, problems
public SelectComponent(ProcessingComponent delegate, Constraint constraint, Map<String,Object> variables)
PropertyExistence) are evaluated in a fairly limited fashion, essentially operating upon the tuple values themselves.
For example, the
SameNode constraint is satisfied when the selected node has the same path as the constraint's
path. And the
PropertyExistence constraint is satisfied when the
property is represented in the tuple with a non-null value. Similarly,
FullTextSearch always evaluates to true. Obviously these implementations will likely not be sufficient for many
purposes. But in cases where these particular constraints are handled in other ways (and thus not expected to be seen by
this processor), this form may be sufficient.
delegate- the delegate processing component that this component should use to obtain the input tuples; may not be null
constraint- the query constraint; may not be null
variables- the map of variables keyed by their name (as used in
BindVariableNameconstraints); may be null
protected SelectComponent.ConstraintChecker createChecker(TypeSystem types, Schemata schemata, QueryResults.Columns columns, Constraint constraint, Map<String,Object> variables)
SelectComponentto evaluate the supplied
types- the type system; may not be null
schemata- the schemata; may not be null
columns- the definition of the result columns and the tuples; may not be null
constraint- the criteria that this
SelectComponentis to evaluate
variables- the variables that are to be substituted for the various
operands; may not be null
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