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

Interface OSQLFunction

All Known Subinterfaces:
OIndexableSQLFunction, OSQLFunctionFiltered
All Known Implementing Classes:
KillQueryFunction, KillSessionFunction, ListQueriesFunction, ListSessionsFunction, ODatabaseFunction, OLuceneCrossClassSearchFunction, OLuceneSearchFunctionTemplate, OLuceneSearchMoreLikeThisFunction, OLuceneSearchOnClassFunction, OLuceneSearchOnFieldsFunction, OLuceneSearchOnIndexFunction, OSpatialFunctionAbstract, OSpatialFunctionAbstractIndexable, OSQLEnterpriseFunction, OSQLFunctionAbsoluteValue, OSQLFunctionAbstract, OSQLFunctionAstar, OSQLFunctionAverage, OSQLFunctionBoth, OSQLFunctionBothE, OSQLFunctionBothV, OSQLFunctionCoalesce, OSQLFunctionConcat, OSQLFunctionConfigurableAbstract, OSQLFunctionCount, OSQLFunctionDate, OSQLFunctionDecimal, OSQLFunctionDecode, OSQLFunctionDifference, OSQLFunctionDijkstra, OSQLFunctionDistance, OSQLFunctionDistinct, OSQLFunctionDocument, OSQLFunctionEncode, OSQLFunctionEval, OSQLFunctionFirst, OSQLFunctionFormat, OSQLFunctionFormat, OSQLFunctionHeuristicPathFinderAbstract, OSQLFunctionIf, OSQLFunctionIfNull, OSQLFunctionIn, OSQLFunctionIndexKeySize, OSQLFunctionInE, OSQLFunctionIntersect, OSQLFunctionInterval, OSQLFunctionInV, OSQLFunctionLast, OSQLFunctionList, OSQLFunctionMap, OSQLFunctionMathAbstract, OSQLFunctionMax, OSQLFunctionMedian, OSQLFunctionMin, OSQLFunctionMode, OSQLFunctionMove, OSQLFunctionMoveFiltered, OSQLFunctionMultiValueAbstract, OSQLFunctionOut, OSQLFunctionOutE, OSQLFunctionOutV, OSQLFunctionPathFinder, OSQLFunctionPercentile, OSQLFunctionSequence, OSQLFunctionSet, OSQLFunctionShortestPath, OSQLFunctionStandardDeviation, OSQLFunctionStrcmpci, OSQLFunctionSum, OSQLFunctionSymmetricDifference, OSQLFunctionSysdate, OSQLFunctionThrowCME, OSQLFunctionTraversedEdge, OSQLFunctionTraversedElement, OSQLFunctionTraversedVertex, OSQLFunctionUnionAll, OSQLFunctionUUID, OSQLFunctionVariance, OSQLStaticReflectiveFunction, OSTAsBinaryFunction, OSTAsGeoJSONFunction, OSTAsTextFunction, OSTBufferFunction, OSTContainsFunction, OSTDisjointFunction, OSTDistanceFunction, OSTDistanceSphereFunction, OSTDWithinFunction, OSTEnvelopFunction, OSTEqualsFunction, OSTGeomFromGeoJSONFunction, OSTGeomFromTextFunction, OSTIntersectsFunction, OSTSrid, OSTWithinFunction
public interface OSQLFunction
Interface that defines a SQL Function. Functions can be state-less if registered as instance, or state-full when registered as class. State-less function are reused across queries, so don't keep any run-time information inside of it. State-full function, instead, stores Implement it and register it with: OSQLParser.getInstance().registerFunction() to being used by the SQL engine.

??? could it be possible to have a small piece of code here showing where to register a function using services ???

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

  • Method Details

    • execute

      Object execute(Object iThis, OIdentifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, OCommandContext iContext)
      Process a record.
      Parameters:
      iThis -
      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

    • config

      void config(Object[] configuredParameters)
      Configure the function.
      Parameters:
      configuredParameters -

    • aggregateResults

      boolean aggregateResults()
      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 getResult(OCommandContext)

      Returns:
      true if function aggregate results

    • filterResult

      boolean filterResult()
      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.

      Returns:
      true if the function acts as a record filter.

    • getName

      String getName()
      Function name, the name is used by the sql parser to identify a call this function.
      Returns:
      String , function name, never null or empty.

    • getMinParams

      int getMinParams()
      Minimum number of parameter this function must have.
      Returns:
      minimum number of parameters

    • getMaxParams

      int getMaxParams()
      Maximum number of parameter this function can handle.
      Returns:
      maximum number of parameters ??? -1 , negative or Integer.MAX_VALUE for unlimited ???

    • getSyntax

      String getSyntax()
      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

      Object getResult(OCommandContext ctx)
      Only called when function aggregates results after all records have been passed to the function.
      Parameters:
      ctx - TODO
      ctx -
      Returns:
      Aggregation result

    • setResult

      void setResult(Object iResult)
      Called by OCommandExecutor, given parameter is the number of results. ??? strange ???
      Parameters:
      iResult -

    • shouldMergeDistributedResult

      boolean shouldMergeDistributedResult()
      This method correspond to distributed query execution
      Returns:
      true if results that comes from different nodes need to be merged to obtain valid one, false otherwise

    • mergeDistributedResult

      Object mergeDistributedResult(List<Object> resultsToMerge)
      This method correspond to distributed query execution
      Parameters:
      resultsToMerge - is the results that comes from different nodes
      Returns:
      is the valid merged result