Package se.liu.ida.hefquin.engine.queryplan.physical.impl

Class PhysicalOpHashRJoin

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOps

se.liu.ida.hefquin.engine.queryplan.physical.impl.PhysicalOpHashRJoin

All Implemented Interfaces:

BinaryPhysicalOp, BinaryPhysicalOpForLogicalOp, PhysicalOperator, PhysicalOperatorForLogicalOperator

public class PhysicalOpHashRJoin
extends BaseForPhysicalOps
implements BinaryPhysicalOpForLogicalOp

A physical operator that implements the hash join algorithm to perform a right outer join of two sequences of input solution mappings (produced by the two sub-plans under this operator). The hash join algorithm builds a hash table with the solution mappings of the first input sequence (using the values that they have for the join variables to decide where to place them in the hash table) and, thereafter, probes the hash table to find join partners for each of the solution mappings of the second input sequence. As this operator performs a right outer join, the solution mappings of the second input sequence that do not have a join partner are not discarded (as would be the case for an inner join) but, instead, are passed to the output as is. The actual algorithm of this operator is implemented in the ExecOpHashRJoin class.

Field Summary

Fields

Modifier and Type	Field	Description
protected final LogicalOpRightJoin	lop

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOps

id

Constructor Summary

Constructors

Constructor	Description
PhysicalOpHashRJoin(LogicalOpRightJoin lop)

Method Summary

Modifier and Type	Method	Description
BinaryExecutableOp	createExecOp(boolean collectExceptions, ExpectedVariables... inputVars)	Creates and returns the executable operator to be used for this physical operator.
boolean	equals(Object o)
ExpectedVariables	getExpectedVariables(ExpectedVariables... inputVars)	Returns the variables that can be expected in the solution mappings produced by this operator if the input(s) to this operator contain solutions mappings with the given set(s) of variables.
BinaryLogicalOp	getLogicalOperator()	Returns the logical operator implemented by this physical operator.
int	hashCode()
String	toString()
void	visit(PhysicalPlanVisitor visitor)

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOps

getID

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.physical.PhysicalOperator

getID

Field Details

lop

protected final LogicalOpRightJoin lop

Constructor Details

PhysicalOpHashRJoin

public PhysicalOpHashRJoin(LogicalOpRightJoin lop)

Method Details

getLogicalOperator

public BinaryLogicalOp getLogicalOperator()

Description copied from interface: PhysicalOperatorForLogicalOperator

Returns the logical operator implemented by this physical operator.

Specified by:

getLogicalOperator in interface BinaryPhysicalOpForLogicalOp

Specified by:

getLogicalOperator in interface PhysicalOperatorForLogicalOperator

getExpectedVariables

public ExpectedVariables getExpectedVariables(ExpectedVariables... inputVars)

Description copied from interface: PhysicalOperator

Returns the variables that can be expected in the solution mappings produced by this operator if the input(s) to this operator contain solutions mappings with the given set(s) of variables. The number of ExpectedVariables objects passed to this method must be in line with the degree of this operator (e.g., for a unary operator, exactly one such object must be passed).

Specified by:

getExpectedVariables in interface PhysicalOperator

createExecOp

public BinaryExecutableOp createExecOp(boolean collectExceptions,
 ExpectedVariables... inputVars)

Description copied from interface: PhysicalOperator

Creates and returns the executable operator to be used for this physical operator. The implementation of this method has to create a new ExecutableOperator object each time it is called. The given collectExceptions flag is passed to the executable operator and determines whether that operator collects its exceptions (see ExecutableOperator.getExceptionsCaughtDuringExecution()) or throws them immediately. The number of ExpectedVariables objects passed as arguments to this method must be in line with the degree of this operator (e.g., for a unary operator, exactly one such object must be passed).

Specified by:

createExecOp in interface BinaryPhysicalOp

Specified by:

createExecOp in interface PhysicalOperator

visit

public void visit(PhysicalPlanVisitor visitor)

Specified by:

visit in interface PhysicalOperator

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object