org.apache.lens.cube.parse

Class JoinCandidate

java.lang.Object

org.apache.lens.cube.parse.JoinCandidate

All Implemented Interfaces:

Candidate

public class JoinCandidate
extends Object
implements Candidate

Represents a join of two candidates

Constructor Summary

Constructors

Constructor and Description
JoinCandidate(Candidate childCandidate1, Candidate childCandidate2, CubeQueryContext cubeql)

Method Summary

Modifier and Type	Method and Description
void	addAnswerableMeasurePhraseIndices(int index) Add `index` as answerable index in a pre-decided list of queried phrases.
boolean	contains(Candidate candidate) Returns true if this candidate contains the given candidate
Set<Integer>	decideMeasurePhrasesToAnswer(Set<Integer> measureIndices)
boolean	evaluateCompleteness(TimeRange timeRange, TimeRange parentTimeRange, boolean failOnPartialData) Calculates if this candidate can answer the query for given time range based on actual data registered with the underlying candidate storages.
JoinCandidate	explode() Explode this candidate into another candidate.
Set<Integer>	getAnswerableMeasurePhraseIndices() Gets the index positions of answerable measure phrases in CubeQueryContext#selectPhrases
List<Candidate>	getChildren() Child candidates that will participate in the join
Optional<Date>	getColumnEndTime(String column) This method should give end time of a column, if there's any.
Collection<String>	getColumns() Returns all the fact columns
Optional<Date>	getColumnStartTime(String column) This method should give start time of a column, if there's any.
OptionalDouble	getCost()
CubeQueryContext	getCubeQueryContext() A candidate always works along with its cube query context.
Date	getEndTime() End Time for this candidate (calculated based on schema)
Set<FactPartition>	getParticipatingPartitions() Returns the set of fact partitions that will participate in this candidate.
Date	getStartTime() Start Time for this candidate (calculated based on schema)
boolean	isDimAttributeEvaluable(String dim) Checks whether a dim attribute is evaluable by this candidate
boolean	isExpressionEvaluable(org.apache.lens.cube.parse.ExpressionResolver.ExpressionContext expr) Checks whether an expression is evaluable by this candidate 1.
boolean	isExpressionEvaluable(String expr) Checks whether an expression is evaluable by this candidate 1.
boolean	isPhraseAnswerable(org.apache.lens.cube.parse.QueriedPhraseContext phrase) Checks whether the given queries phrase is evaluable by this candidate
boolean	isTimeRangeCoverable(TimeRange timeRange) Is time range coverable based on start and end times configured in schema for the composing storage candidates and valid update periods.
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.lens.cube.parse.Candidate

copy, coveredPhrases, getChildrenCount, getConf, getCube, getCubeMetastoreClient, hasColumn, isColumnPresentAndValidForRange, isColumnValidForRange, isCompletelyValidForTimeRanges, isPartiallyValidForTimeRange, isPartiallyValidForTimeRanges, toQueryWriterContext, updateStorageCandidateQueriablePhraseIndices

Constructor Detail

JoinCandidate

public JoinCandidate(Candidate childCandidate1,
                     Candidate childCandidate2,
                     CubeQueryContext cubeql)

Method Detail

getColumns

public Collection<String> getColumns()

Description copied from interface: Candidate

Returns all the fact columns

Specified by:

getColumns in interface Candidate

Returns:

collection of column names

getStartTime

public Date getStartTime()

Description copied from interface: Candidate

Start Time for this candidate (calculated based on schema)

Specified by:

getStartTime in interface Candidate

Returns:

start time of this candidate

getEndTime

public Date getEndTime()

Description copied from interface: Candidate

End Time for this candidate (calculated based on schema)

Specified by:

getEndTime in interface Candidate

Returns:

end time of this candidate

getCost

public OptionalDouble getCost()

Specified by:

getCost in interface Candidate

Returns:

the cost of this candidate

contains

public boolean contains(Candidate candidate)

Description copied from interface: Candidate

Returns true if this candidate contains the given candidate

Specified by:

contains in interface Candidate

Parameters:

candidate - candidate to check

Returns:

whether this contains the candidate in question

evaluateCompleteness

public boolean evaluateCompleteness(TimeRange timeRange,
                                    TimeRange parentTimeRange,
                                    boolean failOnPartialData)
                             throws LensException

Description copied from interface: Candidate

Calculates if this candidate can answer the query for given time range based on actual data registered with the underlying candidate storages. This method will also update any internal candidate data structures that are required for writing the re-written query and to answer Candidate.getParticipatingPartitions().

Specified by:

evaluateCompleteness in interface Candidate

Parameters:

timeRange - : TimeRange to check completeness for. TimeRange consists of start time, end time and the partition column

parentTimeRange - : User quried timerange

failOnPartialData - : fail fast if the candidate can answer the query only partially

Returns:

true if this Candidate can answer query for the given time range.

Throws:

LensException

getParticipatingPartitions

public Set<FactPartition> getParticipatingPartitions()

Description copied from interface: Candidate

Returns the set of fact partitions that will participate in this candidate. Note: This method can be called only after call to Candidate.evaluateCompleteness(TimeRange, TimeRange, boolean)

Specified by:

getParticipatingPartitions in interface Candidate

Returns:

all the partitions from the children

isExpressionEvaluable

public boolean isExpressionEvaluable(org.apache.lens.cube.parse.ExpressionResolver.ExpressionContext expr)

Description copied from interface: Candidate

Checks whether an expression is evaluable by this candidate 1. For a JoinCandidate, atleast one of the child candidates should be able to answer the expression 2. For a UnionCandidate, all child candidates should answer the expression

Specified by:

isExpressionEvaluable in interface Candidate

Parameters:

expr - Expression to be evaluated for Candidate

Returns:

Whether the given expression is evaluable or not

isExpressionEvaluable

public boolean isExpressionEvaluable(String expr)

Description copied from interface: Candidate

Checks whether an expression is evaluable by this candidate 1. For a JoinCandidate, atleast one of the child candidates should be able to answer the expression 2. For a UnionCandidate, all child candidates should answer the expression

Specified by:

isExpressionEvaluable in interface Candidate

Parameters:

expr - Expression to be evaluated for Candidate

Returns:

Whether the given expression is evaluable or not

isDimAttributeEvaluable

public boolean isDimAttributeEvaluable(String dim)
                                throws LensException

Description copied from interface: Candidate

Checks whether a dim attribute is evaluable by this candidate

Specified by:

isDimAttributeEvaluable in interface Candidate

Parameters:

dim - dim attribute

Returns:

whether the dim attribute is evaluable by this candidate

Throws:

LensException - propageted exception

getAnswerableMeasurePhraseIndices

public Set<Integer> getAnswerableMeasurePhraseIndices()

Description copied from interface: Candidate

Gets the index positions of answerable measure phrases in CubeQueryContext#selectPhrases

Specified by:

getAnswerableMeasurePhraseIndices in interface Candidate

Returns:

set of indices of answerable phrases

isPhraseAnswerable

public boolean isPhraseAnswerable(org.apache.lens.cube.parse.QueriedPhraseContext phrase)
                           throws LensException

Description copied from interface: Candidate

Checks whether the given queries phrase is evaluable by this candidate

Specified by:

isPhraseAnswerable in interface Candidate

Parameters:

phrase - Phrase to check

Returns:

whether the phrase is evaluable by this candidate

Throws:

LensException - propagated exception

addAnswerableMeasurePhraseIndices

public void addAnswerableMeasurePhraseIndices(int index)

Description copied from interface: Candidate

Add `index` as answerable index in a pre-decided list of queried phrases.

Specified by:

addAnswerableMeasurePhraseIndices in interface Candidate

Parameters:

index - index to mark as answerable

getColumnStartTime

public Optional<Date> getColumnStartTime(String column)

Description copied from interface: Candidate

This method should give start time of a column, if there's any. Else, this should return Optional.absent

Specified by:

getColumnStartTime in interface Candidate

Parameters:

column - column name

Returns:

optional start time of this column

getColumnEndTime

public Optional<Date> getColumnEndTime(String column)

Description copied from interface: Candidate

This method should give end time of a column, if there's any. Else, this should return Optional.absent

Specified by:

getColumnEndTime in interface Candidate

Parameters:

column - column name

Returns:

optional end time of this column

isTimeRangeCoverable

public boolean isTimeRangeCoverable(TimeRange timeRange)
                             throws LensException

Description copied from interface: Candidate

Is time range coverable based on start and end times configured in schema for the composing storage candidates and valid update periods. Note: This method is different from Candidate.evaluateCompleteness(TimeRange, TimeRange, boolean) . isTimeRangeCoverable checks the the possibility of covering time range from schema perspective by using valid storages/update periods while evaluateCompleteness checks if a time range can be covered based on registered partitions. So isTimeRangeCoverable = false implies evaluateCompleteness = false but vice versa is not true.

Specified by:

isTimeRangeCoverable in interface Candidate

Parameters:

timeRange - The time range to check

Returns:

whether this time range is coverable by this candidate

Throws:

LensException - propagated exceptions

toString

public String toString()

Overrides:

toString in class Object

explode

public JoinCandidate explode()
                      throws LensException

Description copied from interface: Candidate

Explode this candidate into another candidate. Generally candidates can return `this` in this method Special case is storage candidate that returns UnionCandidate if there are multiple update periods covered and update periods have different tables.

Specified by:

explode in interface Candidate

Returns:

converted candidate

Throws:

LensException

decideMeasurePhrasesToAnswer

public Set<Integer> decideMeasurePhrasesToAnswer(Set<Integer> measureIndices)
                                          throws LensException

Specified by:

decideMeasurePhrasesToAnswer in interface Candidate

Throws:

LensException

getChildren

@Generated(value="lombok")
public List<Candidate> getChildren()

Child candidates that will participate in the join

Specified by:

getChildren in interface Candidate

Returns:

child candidates if this is a complex candidate, else null

getCubeQueryContext

@Generated(value="lombok")
public CubeQueryContext getCubeQueryContext()

Description copied from interface: Candidate

A candidate always works along with its cube query context. So a top level method to retrieve that.

Specified by:

getCubeQueryContext in interface Candidate

Returns:

cube query context for this candidate.