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

Class OSQLFunctionTraversedElement

java.lang.Object

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

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

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

All Implemented Interfaces:

OSQLFunction

Direct Known Subclasses:

OSQLFunctionTraversedEdge, OSQLFunctionTraversedVertex

public class OSQLFunctionTraversedElement
extends OSQLFunctionConfigurableAbstract

Returns a traversed element from the stack. Use it with SQL traverse only.

Author:

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

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME

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
OSQLFunctionTraversedElement()
OSQLFunctionTraversedElement(String name)

Method Summary

Modifier and Type	Method and Description
boolean	aggregateResults() A function can make calculation on several records before returning a result.
protected Object	evaluate(Object[] iParams, OCommandContext iContext, String iClassName)
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.
Object	getResult() Only called when function aggregates results after all records have been passed to the function.
String	getSyntax() Returns a convinient SQL String representation of the function.

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

config, toString

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

getDistributedStorageId, getMaxParams, getMinParams, getName, mergeDistributedResult, returnDistributedResult, setResult, shouldMergeDistributedResult

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

OSQLFunctionTraversedElement

public OSQLFunctionTraversedElement()

OSQLFunctionTraversedElement

public OSQLFunctionTraversedElement(String name)

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 Object 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

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 convinient SQL String representation of the function.

Example :

  myFunction( param1, param2, [optionalParam3])
 

This text will be used in exception messages.

Returns:

String , never null.

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

evaluate

protected Object evaluate(Object[] iParams,
                          OCommandContext iContext,
                          String iClassName)