Examples with LambdaGroupByAccumulate org.drools.modelcompiler.constraints.LambdaGroupByAccumulate used on opensource projects

Example 1 with LambdaGroupByAccumulate

use of org.drools.modelcompiler.constraints.LambdaGroupByAccumulate in project drools by kiegroup.

the class KiePackagesBuilder method buildAccumulate.

private Accumulate buildAccumulate(RuleContext ctx, AccumulatePattern accPattern, RuleConditionElement source, Pattern pattern, Set<String> usedVariableName, Collection<Binding> bindings) {
    boolean isGroupBy = accPattern instanceof GroupByPattern;
    AccumulateFunction[] accFunctions = accPattern.getAccumulateFunctions();
    Declaration groupByDeclaration = null;
    Class selfType = (isGroupBy || accFunctions.length > 1) ? Object[].class : accFunctions[0].getResult().getType();
    InternalReadAccessor selfReader = new SelfReferenceClassFieldReader(selfType);
    int arrayIndexOffset = 0;
    if (isGroupBy) {
        if (accFunctions.length == 0) {
            // In this situation the result is anonymous, but it still uses element position 0.
            // For this reason the i used to populate hte array index must be offset by 1.
            accFunctions = new AccumulateFunction[] { new AccumulateFunction(null, CountAccumulateFunction::new) };
            arrayIndexOffset = 1;
        }
        // GroupBy  key is always the last element in the result array
        Variable groupVar = ((GroupByPattern<?, ?>) accPattern).getVarKey();
        groupByDeclaration = new Declaration(groupVar.getName(), new ArrayElementReader(selfReader, accFunctions.length, groupVar.getType()), pattern, true);
        pattern.addDeclaration(groupByDeclaration);
    }
    Accumulate accumulate;
    Accumulator[] accumulators = new Accumulator[accFunctions.length];
    List<Declaration> requiredDeclarationList = new ArrayList<>();
    for (int i = 0; i < accFunctions.length; i++) {
        Variable boundVar = processFunctions(ctx, accPattern, source, pattern, usedVariableName, bindings, isGroupBy, accFunctions[i], selfReader, accumulators, requiredDeclarationList, arrayIndexOffset, i);
        if (isGroupBy) {
            ctx.addGroupByDeclaration(((GroupByPattern) accPattern).getVarKey(), groupByDeclaration);
        }
    }
    if (accFunctions.length == 1) {
        accumulate = new SingleAccumulate(source, requiredDeclarationList.toArray(new Declaration[requiredDeclarationList.size()]), accumulators[0]);
    } else {
        if (source instanceof Pattern) {
            requiredDeclarationList.forEach(((Pattern) source)::addDeclaration);
        }
        accumulate = new MultiAccumulate(source, new Declaration[0], accumulators, // if this is a groupby +1 for the key
        accumulators.length + ((isGroupBy) ? 1 : 0));
    }
    if (isGroupBy) {
        GroupByPatternImpl groupBy = (GroupByPatternImpl) accPattern;
        Declaration[] groupingDeclarations = new Declaration[groupBy.getVars().length];
        for (int i = 0; i < groupBy.getVars().length; i++) {
            groupingDeclarations[i] = ctx.getDeclaration(groupBy.getVars()[i]);
        }
        accumulate = new LambdaGroupByAccumulate(accumulate, groupingDeclarations, groupBy.getGroupingFunction());
    }
    for (Variable boundVar : accPattern.getBoundVariables()) {
        ctx.addAccumulateSource(boundVar, accumulate);
    }
    return accumulate;
}