Package com.orientechnologies.orient.core.sql.functions.coll

Class OSQLFunctionMultiValueAbstract<T>

java.lang.Object

com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

com.orientechnologies.orient.core.sql.functions.coll.OSQLFunctionMultiValueAbstract<T>

All Implemented Interfaces:

OSQLFunction

Direct Known Subclasses:

OSQLFunctionDifference, OSQLFunctionDocument, OSQLFunctionIntersect, OSQLFunctionList, OSQLFunctionMap, OSQLFunctionSet, OSQLFunctionSymmetricDifference, OSQLFunctionUnionAll

public abstract class OSQLFunctionMultiValueAbstract<T>
extends OSQLFunctionConfigurableAbstract

Abstract class for multi-value based function implementations.

Author:

Luca Garulli (l.garulli--(at)--orientdb.com)

Field Summary

Fields

Modifier and Type	Field	Description
protected T	context

Fields inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

configuredParameters

Fields inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

maxParams, minParams, name

Constructor Summary

Constructors

Constructor	Description
OSQLFunctionMultiValueAbstract(String iName, int iMinParams, int iMaxParams)

Method Summary

Modifier and Type	Method	Description
boolean	aggregateResults()	A function can make calculation on several records before returning a result.
T	getResult(OCommandContext ctx)	Only called when function aggregates results after all records have been passed to the function.
boolean	shouldMergeDistributedResult()	This method correspond to distributed query execution

Methods inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionConfigurableAbstract

config, toString

Methods inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

filterResult, getDatabase, getDistributedStorageId, getMaxParams, getMinParams, getName, getSingleItem, getSingleProperty, mergeDistributedResult, returnDistributedResult, setResult

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.orientechnologies.orient.core.sql.functions.OSQLFunction

execute, getSyntax

Field Details

context

protected T context

Constructor Details

OSQLFunctionMultiValueAbstract

public OSQLFunctionMultiValueAbstract(String iName,
 int iMinParams,
 int iMaxParams)

Method Details

aggregateResults

public boolean aggregateResults()

Description copied from interface: OSQLFunction

A function can make calculation on several records before returning a result.

Example of such function : sum, count, max, min ...

The final result of the aggregation is obtain by calling OSQLFunction.getResult(OCommandContext)

Specified by:

aggregateResults in interface OSQLFunction

Overrides:

aggregateResults in class OSQLFunctionAbstract

Returns:

true if function aggregate results

getResult

public T getResult(OCommandContext ctx)

Description copied from interface: OSQLFunction

Only called when function aggregates results after all records have been passed to the function.

Specified by:

getResult in interface OSQLFunction

Overrides:

getResult in class OSQLFunctionAbstract

Parameters:

ctx - TODO

Returns:

Aggregation result

shouldMergeDistributedResult

public boolean shouldMergeDistributedResult()

Description copied from interface: OSQLFunction

This method correspond to distributed query execution

Specified by:

shouldMergeDistributedResult in interface OSQLFunction

Overrides:

shouldMergeDistributedResult in class OSQLFunctionAbstract

Returns:

true if results that comes from different nodes need to be merged to obtain valid one, false otherwise