Package com.arcadedb.query.sql.function.misc

Class SQLFunctionCount

java.lang.Object

com.arcadedb.query.sql.function.SQLFunctionAbstract

com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

com.arcadedb.query.sql.function.math.SQLFunctionMathAbstract

com.arcadedb.query.sql.function.misc.SQLFunctionCount

All Implemented Interfaces:

SQLFunction

public class SQLFunctionCount
extends SQLFunctionMathAbstract

Count the record that contains a field. Use * to indicate the record instead of the field. Uses the context to save the counter number. When different Number class are used, take the class with most precision.

Author:

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

Field Summary

Fields

Modifier and Type	Field	Description
static String	NAME

Fields inherited from class com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

configuredParameters

Fields inherited from class com.arcadedb.query.sql.function.SQLFunctionAbstract

name

Constructor Summary

Constructors

Constructor	Description
SQLFunctionCount()

Method Summary

Modifier and Type	Method	Description
boolean	aggregateResults()	A function can make calculation on several records before returning a result.
Object	execute(Object iThis, Identifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, CommandContext iContext)	Process a record.
Object	getResult()	Only called when function aggregates results after all records have been passed to the function.
String	getSyntax()	Returns a convenient SQL String representation of the function.

Methods inherited from class com.arcadedb.query.sql.function.math.SQLFunctionMathAbstract

getClassWithMorePrecision, getContextValue

Methods inherited from class com.arcadedb.query.sql.function.SQLFunctionConfigurableAbstract

config, toString

Methods inherited from class com.arcadedb.query.sql.function.SQLFunctionAbstract

getName

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

Constructor Detail

SQLFunctionCount

public SQLFunctionCount()

Method Detail

execute

public Object execute(Object iThis,
                      Identifiable iCurrentRecord,
                      Object iCurrentResult,
                      Object[] iParams,
                      CommandContext iContext)

Description copied from interface: SQLFunction

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

aggregateResults

public boolean aggregateResults()

Description copied from interface: SQLFunction

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 obtained by calling SQLFunction.getResult()

Specified by:

aggregateResults in interface SQLFunction

Overrides:

aggregateResults in class SQLFunctionMathAbstract

Returns:

true if function aggregate results

getSyntax

public String getSyntax()

Description copied from interface: SQLFunction

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.

getResult

public Object getResult()

Description copied from interface: SQLFunction

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

Specified by:

getResult in interface SQLFunction

Overrides:

getResult in class SQLFunctionAbstract

Returns:

Aggregation result