Package org.qdl_lang.util.aggregate

Class QDLAggregateUtil

java.lang.Object

org.qdl_lang.util.aggregate.QDLAggregateUtil

public class QDLAggregateUtil
extends Object

The QDL utility for processing aggregates (stems and sets). This allows for processing each scalar in an aggregate and handles navigating them in turn. Implement or extends the ProcessScalar interface.

Processing aggregates.

You can do them so they follow the standard QDL stem/set contracts when implementing a system function by executing the correct AbstractEvaluator.processN in an evaluator or if you have something specific address each scalar using this utility. This utility in particular is useful when writing Java extensions that implement QDLFunction where the machinery of FunctionEvaluator is not available.

Usage

If you have an aggregate and need to process scalars, call this with the right overrides to IdentityScalarImpl. That class simply passes back its arguments unchanged as a default behavior.

Handling exceptions

If you use this in an extension (so a Java class that extends QDLFunction) then you don't need to do anything special exception throw Java exceptions. If you are using this outside of that, then throws an UnknownTypeException for an unknown type. Since this does not have the actual QDL statement that triggered the error, it is set to null. You should catch the exception when calling this and fill that in with the right value so the user gets the right information.

Constructor Summary

Constructors

Constructor	Description
QDLAggregateUtil()

Method Summary

Modifier and Type	Method	Description
static QDLStem	process(QDLStem stem, ProcessStemAxisRestriction processRankRestriction)	Start processing for an axis restricted function.
static Object	process(QDLValue qdlValue, ProcessScalar processScalar)	Top-level call for this set of utilities.
static QDLSet	processSet(QDLSet<QDLValue> inSet, ProcessScalar processScalar)	Process the elements in a set, including nested sets.
static QDLStem	processStem(QDLStem inStem, List<Object> index, ProcessScalar processScalar)
static QDLStem	processStem(QDLStem inStem, List index, ProcessStemAxisRestriction processRankRestriction, int currentDepth)

Methods inherited from class java.lang.Object

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

Constructor Detail

QDLAggregateUtil

public QDLAggregateUtil()

Method Detail

process

public static Object process(QDLValue qdlValue,
                             ProcessScalar processScalar)

Top-level call for this set of utilities. Create the right scalar processor, then call this on a generic object. A scalar is processed and returned as such, aggregates are processed as aggregates.

Parameters:

qdlValue -

processScalar - implementation of ProcessScalar

Returns:

processStem

public static QDLStem processStem(QDLStem inStem,
                                  List<Object> index,
                                  ProcessScalar processScalar)

processSet

public static QDLSet processSet(QDLSet<QDLValue> inSet,
                                ProcessScalar processScalar)

Process the elements in a set, including nested sets. This will access every element in every set eventually.

Parameters:

inSet -

processScalar -

Returns:

process

public static QDLStem process(QDLStem stem,
                              ProcessStemAxisRestriction processRankRestriction)

Start processing for an axis restricted function. This will throw an exception if the argument is not a stem.

Parameters:

processRankRestriction -

Returns:

processStem

public static QDLStem processStem(QDLStem inStem,
                                  List index,
                                  ProcessStemAxisRestriction processRankRestriction,
                                  int currentDepth)