Package org.apache.druid.query.aggregation.post

Class ExpressionPostAggregator

java.lang.Object

org.apache.druid.query.aggregation.post.ExpressionPostAggregator

All Implemented Interfaces:

Cacheable, PostAggregator

public class ExpressionPostAggregator
extends Object
implements PostAggregator

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	ExpressionPostAggregator.Ordering

Constructor Summary

Constructors

Constructor	Description
ExpressionPostAggregator(String name, String expression, String ordering, ColumnType outputType, Expr parsed)	Constructor for a pre-parsed expression.
ExpressionPostAggregator(String name, String expression, String ordering, ColumnType outputType, ExprMacroTable macroTable)	Constructor for deserialization.

Method Summary

Modifier and Type	Method	Description
Object	compute(Map<String,Object> values)
ExpressionPostAggregator	decorate(Map<String,AggregatorFactory> aggregators)	Allows returning an enriched post aggregator, built from contextual information available from the given map of AggregatorFactory keyed by their names.
boolean	equals(Object o)
byte[]	getCacheKey()	Get a byte array used as a cache key.
Comparator	getComparator()
Set<String>	getDependentFields()
String	getExpression()
String	getName()
String	getOrdering()
ColumnType	getOutputType()
ColumnType	getType(ColumnInspector signature)	Return the output type of a row processed with this post aggregator.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.query.aggregation.PostAggregator

getType

Constructor Details

ExpressionPostAggregator

public ExpressionPostAggregator(String name,
 String expression,
 @Nullable
 String ordering,
 @Nullable
 ColumnType outputType,
 ExprMacroTable macroTable)

Constructor for deserialization.

ExpressionPostAggregator

public ExpressionPostAggregator(String name,
 String expression,
 @Nullable
 String ordering,
 @Nullable
 ColumnType outputType,
 Expr parsed)

Constructor for a pre-parsed expression.

Method Details

getDependentFields

public Set<String> getDependentFields()

Specified by:

getDependentFields in interface PostAggregator

getComparator

public Comparator getComparator()

Specified by:

getComparator in interface PostAggregator

compute

@Nullable
public Object compute(Map<String,Object> values)

Specified by:

compute in interface PostAggregator

getName

public String getName()

Specified by:

getName in interface PostAggregator

getType

public ColumnType getType(ColumnInspector signature)

Description copied from interface: PostAggregator

Return the output type of a row processed with this post aggregator. Refer to the ColumnType javadocs for details on the implications of choosing a type.

Specified by:

getType in interface PostAggregator

Parameters:

signature -

decorate

public ExpressionPostAggregator decorate(Map<String,AggregatorFactory> aggregators)

Description copied from interface: PostAggregator

Allows returning an enriched post aggregator, built from contextual information available from the given map of AggregatorFactory keyed by their names. Callers must call this method before calling PostAggregator.compute(java.util.Map<java.lang.String, java.lang.Object>) or PostAggregator.getComparator(). This is typically done in the constructor of queries which support post aggregators, via Queries.prepareAggregations(java.util.List<org.apache.druid.query.aggregation.AggregatorFactory>, java.util.List<org.apache.druid.query.aggregation.PostAggregator>).

Specified by:

decorate in interface PostAggregator

getExpression

public String getExpression()

getOrdering

@Nullable
public String getOrdering()

getOutputType

@Nullable
public ColumnType getOutputType()

toString

public String toString()

Overrides:

toString in class Object

getCacheKey

public byte[] getCacheKey()

Description copied from interface: Cacheable

Get a byte array used as a cache key.

Specified by:

getCacheKey in interface Cacheable

Returns:

bytes to be used as cache key - or null if this object should not be cached.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object