org.modeshape.jcr.query.process
Class SelectComponent

java.lang.Object
  org.modeshape.jcr.query.process.ProcessingComponent
      org.modeshape.jcr.query.process.DelegatingComponent
          org.modeshape.jcr.query.process.SelectComponent

public class SelectComponent
extends DelegatingComponent

Nested Class Summary

protected static interface	SelectComponent.CompareOperation Interface defining the Comparison functionality for a specific Operator.
static interface	SelectComponent.ConstraintChecker Interface used to determine whether a tuple satisfies all of the constraints applied to the SELECT node.

Nested classes/interfaces inherited from class org.modeshape.jcr.query.process.ProcessingComponent

ProcessingComponent.DynamicOperation

Constructor Summary

SelectComponent(ProcessingComponent delegate, Constraint constraint, Map<String,Object> variables)
Create a SELECT processing component that pass those tuples that satisfy the supplied constraint.

Method Summary

protected SelectComponent.ConstraintChecker	createChecker(TypeSystem types, Schemata schemata, QueryResults.Columns columns, Constraint constraint, Map<String,Object> variables) Create the constraint evaluator that is used by the SelectComponent to evaluate the supplied criteria.
protected SelectComponent.ConstraintChecker	createChecker(TypeSystem types, Schemata schemata, QueryResults.Columns columns, ProcessingComponent.DynamicOperation dynamicOperation, Operator operator, StaticOperand staticOperand)
protected static Pattern	createRegexFromLikeExpression(String likeExpression)
List<Object[]>	execute() Execute this stage of processing and return the resulting tuples that each conform to the columns.

Methods inherited from class org.modeshape.jcr.query.process.DelegatingComponent

close, delegate

Methods inherited from class org.modeshape.jcr.query.process.ProcessingComponent

createDynamicOperation, createSortComparator, emptyTuples, getColumns, getContext, problems

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SelectComponent

public SelectComponent(ProcessingComponent delegate,
                       Constraint constraint,
                       Map<String,Object> variables)

Create a SELECT processing component that pass those tuples that satisfy the supplied constraint. Certain constraints (including FullTextSearch, SameNode and 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.

Parameters:

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 BindVariableName constraints); may be null

Method Detail

execute

public List<Object[]> execute()

Description copied from class: ProcessingComponent

Execute this stage of processing and return the resulting tuples that each conform to the columns.

Specified by:

execute in class ProcessingComponent

Returns:

the list of tuples, where each tuple corresonds to the columns; never null

createChecker

protected SelectComponent.ConstraintChecker createChecker(TypeSystem types,
                                                          Schemata schemata,
                                                          QueryResults.Columns columns,
                                                          Constraint constraint,
                                                          Map<String,Object> variables)

Create the constraint evaluator that is used by the SelectComponent to evaluate the supplied criteria.

Parameters:

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 SelectComponent is to evaluate

variables - the variables that are to be substituted for the various BindVariableName operands; may not be null

Returns:

the constraint evaluator; never null

createChecker

protected SelectComponent.ConstraintChecker createChecker(TypeSystem types,
                                                          Schemata schemata,
                                                          QueryResults.Columns columns,
                                                          ProcessingComponent.DynamicOperation dynamicOperation,
                                                          Operator operator,
                                                          StaticOperand staticOperand)

createRegexFromLikeExpression

protected static Pattern createRegexFromLikeExpression(String likeExpression)