org.apache.jackrabbit.core.query.lucene.join
Class OperandEvaluator

java.lang.Object
  org.apache.jackrabbit.core.query.lucene.join.OperandEvaluator

public class OperandEvaluator
extends Object

Evaluator of QOM operands. This class evaluates operands in the context of a value factory, a set of bind variables and possibly a query result row.

Constructor Summary

OperandEvaluator(ValueFactory factory, Map<String,Value> variables)
Creates an operand evaluator for the given value factory and set of bind variables.

Method Summary

Value	getValue(Operand operand, Row row) Returns the value of the given operand in the context of the given row.
Value	getValue(StaticOperand operand) Returns the value of the given static operand (literal or bind variable).
Value	getValue(StaticOperand operand, int type)
Value[]	getValues(Operand operand, Row row) Evaluates the given operand in the context of the given row.

Methods inherited from class java.lang.Object

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

Constructor Detail

OperandEvaluator

public OperandEvaluator(ValueFactory factory,
                        Map<String,Value> variables)

Creates an operand evaluator for the given value factory and set of bind variables.

Parameters:

factory - value factory

variables - bind variables

Method Detail

getValue

public Value getValue(StaticOperand operand,
                      int type)
               throws RepositoryException

Throws:

RepositoryException

getValue

public Value getValue(StaticOperand operand)
               throws RepositoryException

Returns the value of the given static operand (literal or bind variable).

Parameters:

operand - static operand to be evaluated

Returns:

evaluated value

Throws:

RepositoryException - if a named bind variable is not found, or if the operand type is unknown

getValue

public Value getValue(Operand operand,
                      Row row)
               throws RepositoryException

Returns the value of the given operand in the context of the given row. This is a convenience method that uses a somewhat lossy best-effort mapping to evaluate multi-valued operands to a single value. Use the getValues(Operand, Row) method for more accurate results.

Parameters:

operand - operand to be evaluated

row - query result row

Returns:

evaluated value

Throws:

RepositoryException

getValues

public Value[] getValues(Operand operand,
                         Row row)
                  throws RepositoryException

Evaluates the given operand in the context of the given row.

Parameters:

operand - operand to be evaluated

row - query result row

Returns:

values of the operand at the given row

Throws:

RepositoryException - if the operand can't be evaluated