Package org.apache.druid.segment.join.lookup

Class LookupJoinMatcher

java.lang.Object

org.apache.druid.segment.join.lookup.LookupJoinMatcher

All Implemented Interfaces:

JoinMatcher

public class LookupJoinMatcher
extends Object
implements JoinMatcher

Method Summary

Modifier and Type	Method	Description
static LookupJoinMatcher	create(LookupExtractor extractor, ColumnSelectorFactory leftSelectorFactory, JoinConditionAnalysis condition, boolean remainderNeeded)
ColumnSelectorFactory	getColumnSelectorFactory()	Returns a factory for reading columns from the Joinable that correspond to matched rows.
boolean	hasMatch()	Returns whether the active matcher (JoinMatcher.matchCondition() or JoinMatcher.matchRemainder()) has matched something.
void	matchCondition()	Matches against the ColumnSelectorFactory and JoinConditionAnalysis supplied to Joinable.makeJoinMatcher(org.apache.druid.segment.ColumnSelectorFactory, org.apache.druid.segment.join.JoinConditionAnalysis, boolean, org.apache.druid.java.util.common.io.Closer).
boolean	matchingRemainder()	Returns whether this matcher is currently matching the remainder (i.e.
void	matchRemainder()	Matches every row that has not already been matched.
void	nextMatch()	Moves on to the next match.
void	reset()	Clears any active matches.

Methods inherited from class java.lang.Object

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

Method Details

create

public static LookupJoinMatcher create(LookupExtractor extractor,
 ColumnSelectorFactory leftSelectorFactory,
 JoinConditionAnalysis condition,
 boolean remainderNeeded)

getColumnSelectorFactory

public ColumnSelectorFactory getColumnSelectorFactory()

Description copied from interface: JoinMatcher

Returns a factory for reading columns from the Joinable that correspond to matched rows.

Specified by:

getColumnSelectorFactory in interface JoinMatcher

matchCondition

public void matchCondition()

Description copied from interface: JoinMatcher

Matches against the ColumnSelectorFactory and JoinConditionAnalysis supplied to Joinable.makeJoinMatcher(org.apache.druid.segment.ColumnSelectorFactory, org.apache.druid.segment.join.JoinConditionAnalysis, boolean, org.apache.druid.java.util.common.io.Closer). After calling this method, JoinMatcher.hasMatch() will return whether at least one row matched. After reading that row, JoinMatcher.nextMatch() can be used to move on to the next row.

Specified by:

matchCondition in interface JoinMatcher

matchRemainder

public void matchRemainder()

Description copied from interface: JoinMatcher

Matches every row that has not already been matched. Used for right joins. After calling this method, JoinMatcher.hasMatch() will return whether at least one row matched. After reading that row, JoinMatcher.nextMatch() can be used to move on to the next row. Will only work correctly if Joinable.makeJoinMatcher(org.apache.druid.segment.ColumnSelectorFactory, org.apache.druid.segment.join.JoinConditionAnalysis, boolean, org.apache.druid.java.util.common.io.Closer) was called with remainderNeeded == true.

Specified by:

matchRemainder in interface JoinMatcher

hasMatch

public boolean hasMatch()

Description copied from interface: JoinMatcher

Returns whether the active matcher (JoinMatcher.matchCondition() or JoinMatcher.matchRemainder()) has matched something.

Specified by:

hasMatch in interface JoinMatcher

matchingRemainder

public boolean matchingRemainder()

Description copied from interface: JoinMatcher

Returns whether this matcher is currently matching the remainder (i.e. if JoinMatcher.matchRemainder() was the most recent match method called).

Specified by:

matchingRemainder in interface JoinMatcher

nextMatch

public void nextMatch()

Description copied from interface: JoinMatcher

Moves on to the next match. It is only valid to call this if JoinMatcher.hasMatch() is true.

Specified by:

nextMatch in interface JoinMatcher

reset

public void reset()

Description copied from interface: JoinMatcher

Clears any active matches. Does not clear memory about what has been matched in the past.

Specified by:

reset in interface JoinMatcher