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

Class PhysicalOpHashJoin

java.lang.Object

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

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

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

All Implemented Interfaces:

BinaryPhysicalOp, BinaryPhysicalOpForLogicalOp, PhysicalOperator, PhysicalOperatorForLogicalOperator

public class PhysicalOpHashJoin
extends BaseForPhysicalOpBinaryJoin

A physical operator that implements the hash join algorithm to perform an inner 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. The actual algorithm of this operator is implemented in the ExecOpHashJoin class.

Field Summary

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

lop

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

id

Constructor Summary

Constructors

Constructor	Description
PhysicalOpHashJoin(LogicalOpJoin 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)
String	toString()
void	visit(PhysicalPlanVisitor visitor)

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

getExpectedVariables, getLogicalOperator, hashCode

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

Constructor Details

PhysicalOpHashJoin

public PhysicalOpHashJoin(LogicalOpJoin lop)

Method Details

equals

public boolean equals(Object o)

Overrides:

equals in class BaseForPhysicalOpBinaryJoin

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).

visit

public void visit(PhysicalPlanVisitor visitor)

toString

public String toString()

Overrides:

toString in class Object