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

Class OSQLFunctionDistinct

java.lang.Object

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

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

All Implemented Interfaces:

OSQLFunction

public class OSQLFunctionDistinct
extends OSQLFunctionAbstract

Keeps items only once removing duplicates

Author:

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

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAME

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

maxParams, minParams, name

Constructor Summary

Constructors

Constructor	Description
OSQLFunctionDistinct()

Method Summary

Modifier and Type	Method	Description
Object	execute(Object iThis, OIdentifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, OCommandContext iContext)	Process a record.
boolean	filterResult()	A function can act both as transformation or filtering records.
String	getSyntax()	Returns a convenient SQL String representation of the function.

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

aggregateResults, config, getDatabase, getDistributedStorageId, getMaxParams, getMinParams, getName, getResult, getSingleItem, getSingleProperty, mergeDistributedResult, returnDistributedResult, setResult, shouldMergeDistributedResult, toString

Methods inherited from class java.lang.Object

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

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

Constructor Details

OSQLFunctionDistinct

public OSQLFunctionDistinct()

Method Details

execute

public Object execute(Object iThis,
 OIdentifiable iCurrentRecord,
 Object iCurrentResult,
 Object[] iParams,
 OCommandContext iContext)

Description copied from interface: OSQLFunction

Process a record.

iCurrentRecord - : current record

iCurrentResult - TODO

iParams - : function parameters, number is ensured to be within minParams and maxParams.

iContext - : object calling this function

Returns:

function result, can be null. Special cases : can be null if function aggregate results, can be null if function filter results : this mean result is excluded

filterResult

public boolean filterResult()

Description copied from interface: OSQLFunction

A function can act both as transformation or filtering records. If the function may reduce the number final records than it must return true.

Function should return null for the execute method if the record must be excluded.

Specified by:

filterResult in interface OSQLFunction

Overrides:

filterResult in class OSQLFunctionAbstract

Returns:

true if the function acts as a record filter.

getSyntax

public String getSyntax()

Description copied from interface: OSQLFunction

Returns a convenient SQL String representation of the function.

Example :

  myFunction( param1, param2, [optionalParam3])
 

This text will be used in exception messages.

Returns:

String , never null.