Class BaseForExecOps

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

All Implemented Interfaces:

StatsProvider, ExecutableOperator

Direct Known Subclasses:

BinaryExecutableOpBase, NaryExecutableOpBase, NullaryExecutableOpBase, UnaryExecutableOpBase

public abstract class BaseForExecOps
extends Object
implements ExecutableOperator

Top-level base class for all implementations of ExecutableOperator. This base class handles the collection of exceptions that may occur during the execution of the algorithm implemented by an executable operator, and it stores the QueryPlanningInfo (if any).

Field Summary

Fields

Modifier and Type	Field	Description
protected final boolean	collectExceptions	If true, then the subclasses are expected to collect exceptions (by calling recordExceptionCaughtDuringExecution(Exception)); otherwise, they are expected to throw the exceptions immediately.
protected final boolean	mayReduce	If true, then the executable operator is permitted (and encouraged) to reduce duplicate solution mappings as part of its execution; otherwise, the operator must preserve duplicates.
protected final QueryPlanningInfo	qpInfo	May be null.

Constructor Summary

Constructors

Constructor	Description
BaseForExecOps(boolean mayReduce, boolean collectExceptions, QueryPlanningInfo qpInfo)

Method Summary

Modifier and Type	Method	Description
List<Exception>	getExceptionsCaughtDuringExecution()	Returns exceptions that were caught and collected during the execution of this operator (if any).
QueryPlanningInfo	getQueryPlanningInfo()	Returns the QueryPlanningInfo object that was populated for a physical plan whose root operator was the physical operator for which this executable operator was created.
boolean	mayReduce()	Indicates whether this executable operator is permitted (and potentially encouraged) to reduce duplicate solution mappings as part of its execution.
protected void	recordExceptionCaughtDuringExecution(Exception e)

Methods inherited from class java.lang.Object

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

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.executable.ExecutableOperator

getStats

Methods inherited from interface se.liu.ida.hefquin.base.utils.StatsProvider

resetStats

Field Details

qpInfo

protected final QueryPlanningInfo qpInfo

May be null.

collectExceptions

protected final boolean collectExceptions

If true, then the subclasses are expected to collect exceptions (by calling recordExceptionCaughtDuringExecution(Exception)); otherwise, they are expected to throw the exceptions immediately.

mayReduce

protected final boolean mayReduce

If true, then the executable operator is permitted (and encouraged) to reduce duplicate solution mappings as part of its execution; otherwise, the operator must preserve duplicates.

Constructor Details

BaseForExecOps

public BaseForExecOps(boolean mayReduce,
 boolean collectExceptions,
 QueryPlanningInfo qpInfo)

Parameters:

collectExceptions - - if true, then the subclasses are expected to collect exceptions (by calling recordExceptionCaughtDuringExecution(Exception)); otherwise, they are expected to throw the exceptions immediately

qpInfo - - may be null

Method Details

getQueryPlanningInfo

public QueryPlanningInfo getQueryPlanningInfo()

Description copied from interface: ExecutableOperator

Returns the QueryPlanningInfo object that was populated for a physical plan whose root operator was the physical operator for which this executable operator was created.

Specified by:

getQueryPlanningInfo in interface ExecutableOperator

Returns:

the QueryPlanningInfo object or null.

getExceptionsCaughtDuringExecution

public List<Exception> getExceptionsCaughtDuringExecution()

Description copied from interface: ExecutableOperator

Returns exceptions that were caught and collected during the execution of this operator (if any). If no exceptions were caught (which should be the normal case), then this function returns an empty list.

Specified by:

getExceptionsCaughtDuringExecution in interface ExecutableOperator

mayReduce

public boolean mayReduce()

Description copied from interface: ExecutableOperator

Indicates whether this executable operator is permitted (and potentially encouraged) to reduce duplicate solution mappings as part of its execution.

If this method returns true, the operator may remove duplicate solution mappings if it has the capability to do so. If it returns false, the operator must preserve duplicates, even if it would otherwise be able to eliminate them.

Specified by:

mayReduce in interface ExecutableOperator

Returns:

true if the operator may reduce duplicates; false otherwise.

recordExceptionCaughtDuringExecution

protected void recordExceptionCaughtDuringExecution(Exception e)