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--orientechnologies.com)

Field Summary

Fields

Modifier and Type	Field and 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 and Description
OSQLFunctionMultiValueAbstract(String iName, int iMinParams, int iMaxParams)

Method Summary

Modifier and Type	Method and Description
boolean	aggregateResults() A function can make calculation on several records before returning a result.
T	getResult() 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, getDistributedStorageId, getMaxParams, getMinParams, getName, 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 Detail

context

protected T context

Constructor Detail

OSQLFunctionMultiValueAbstract

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

Method Detail

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()

Specified by:

aggregateResults in interface OSQLFunction

Overrides:

aggregateResults in class OSQLFunctionAbstract

Returns:

true if function aggregate results

getResult

public T getResult()

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

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