Examples with Clause org.apache.asterix.lang.common.base.Clause used on opensource projects

Example 6 with Clause

use of org.apache.asterix.lang.common.base.Clause in project asterixdb by apache.

the class AqlExpressionToPlanTranslator method expressionNeedsNoNesting.

@Override
protected boolean expressionNeedsNoNesting(Expression expr) {
    boolean isFLWOGR = expr.getKind() == Kind.FLWOGR_EXPRESSION;
    boolean letOnly = true;
    // No nesting is needed for a FLWOR expression that only has LETs and RETURN.
    if (isFLWOGR) {
        FLWOGRExpression flwor = (FLWOGRExpression) expr;
        for (Clause clause : flwor.getClauseList()) {
            letOnly &= clause.getClauseType() == Clause.ClauseType.LET_CLAUSE;
        }
    }
    return (isFLWOGR && letOnly) || super.expressionNeedsNoNesting(expr);
}

Example 7 with Clause

use of org.apache.asterix.lang.common.base.Clause in project asterixdb by apache.

the class AqlPlusExpressionToPlanTranslator method visitJoinClause.

@Override
public Pair<ILogicalOperator, LogicalVariable> visitJoinClause(JoinClause jc, Mutable<ILogicalOperator> tupSource) throws CompilationException {
    Mutable<ILogicalOperator> opRef = tupSource;
    Pair<ILogicalOperator, LogicalVariable> leftSide = null;
    for (Clause c : jc.getLeftClauses()) {
        leftSide = c.accept(this, opRef);
        opRef = new MutableObject<ILogicalOperator>(leftSide.first);
    }
    opRef = tupSource;
    Pair<ILogicalOperator, LogicalVariable> rightSide = null;
    for (Clause c : jc.getRightClauses()) {
        rightSide = c.accept(this, opRef);
        opRef = new MutableObject<ILogicalOperator>(rightSide.first);
    }
    Pair<ILogicalExpression, Mutable<ILogicalOperator>> whereCond = langExprToAlgExpression(jc.getWhereExpr(), tupSource);
    AbstractBinaryJoinOperator join;
    switch(jc.getKind()) {
        case INNER:
            join = new InnerJoinOperator(new MutableObject<ILogicalExpression>(whereCond.first));
            break;
        case LEFT_OUTER:
            join = new LeftOuterJoinOperator(new MutableObject<ILogicalExpression>(whereCond.first));
            break;
        default:
            throw new CompilationException(ErrorCode.COMPILATION_AQLPLUS_NO_SUCH_JOIN_TYPE);
    }
    join.getInputs().add(new MutableObject<ILogicalOperator>(leftSide.first));
    join.getInputs().add(new MutableObject<ILogicalOperator>(rightSide.first));
    return new Pair<ILogicalOperator, LogicalVariable>(join, null);
}

Example 8 with Clause

use of org.apache.asterix.lang.common.base.Clause in project asterixdb by apache.

the class AqlExpressionToPlanTranslator method visit.

@Override
public Pair<ILogicalOperator, LogicalVariable> visit(FLWOGRExpression flwor, Mutable<ILogicalOperator> tupSource) throws CompilationException {
    Mutable<ILogicalOperator> flworPlan = tupSource;
    boolean isTop = context.isTopFlwor();
    if (!isTop) {
        context.enterSubplan();
    }
    if (isTop) {
        context.setTopFlwor(false);
    }
    for (Clause c : flwor.getClauseList()) {
        Pair<ILogicalOperator, LogicalVariable> pC = c.accept(this, flworPlan);
        flworPlan = new MutableObject<>(pC.first);
    }
    Expression r = flwor.getReturnExpr();
    boolean noForClause = flwor.noForClause();
    Pair<ILogicalOperator, LogicalVariable> result;
    if (r.getKind() == Kind.VARIABLE_EXPRESSION) {
        VariableExpr v = (VariableExpr) r;
        LogicalVariable var = context.getVar(v.getVar().getId());
        result = produceFlworPlan(noForClause, isTop, flworPlan, var);
    } else {
        Mutable<ILogicalOperator> baseOp = new MutableObject<>(flworPlan.getValue());
        Pair<ILogicalOperator, LogicalVariable> rRes = r.accept(this, baseOp);
        ILogicalOperator rOp = rRes.first;
        ILogicalOperator resOp;
        if (expressionNeedsNoNesting(r)) {
            baseOp.setValue(flworPlan.getValue());
            resOp = rOp;
        } else {
            SubplanOperator s = new SubplanOperator(rOp);
            s.getInputs().add(flworPlan);
            resOp = s;
            baseOp.setValue(new NestedTupleSourceOperator(new MutableObject<ILogicalOperator>(s)));
        }
        Mutable<ILogicalOperator> resOpRef = new MutableObject<>(resOp);
        result = produceFlworPlan(noForClause, isTop, resOpRef, rRes.second);
    }
    if (!isTop) {
        context.exitSubplan();
    }
    return result;
}

Example 9 with Clause

use of org.apache.asterix.lang.common.base.Clause in project asterixdb by apache.

the class ClauseComparator method extractLetBindingVariables.

// Extracts the variables to be substituted.
private Map<VariableExpr, Expression> extractLetBindingVariables(List<Clause> clauses, GroupbyClause cuttingGbyClause) throws CompilationException {
    Map<VariableExpr, Expression> varExprMap = new HashMap<VariableExpr, Expression>();
    int gbyIndex = clauses.indexOf(cuttingGbyClause);
    for (int i = gbyIndex + 1; i < clauses.size(); i++) {
        Clause cl = clauses.get(i);
        if (cl.getClauseType() == ClauseType.LET_CLAUSE) {
            LetClause letClause = (LetClause) cl;
            // inline let variables one by one iteratively.
            letClause.setBindingExpr((Expression) AQLVariableSubstitutionUtil.substituteVariable(letClause.getBindingExpr(), varExprMap));
            varExprMap.put(letClause.getVarExpr(), letClause.getBindingExpr());
        }
    }
    return varExprMap;
}

Example 10 with Clause

use of org.apache.asterix.lang.common.base.Clause in project asterixdb by apache.

the class ClauseComparator method processLeadingLetClauses.

// Processes leading "let"s in a FLWOGR.
private void processLeadingLetClauses(Integer step, List<Clause> clauseList) throws CompilationException {
    List<Clause> processedLetList = new ArrayList<Clause>();
    boolean firstLet = true;
    int size = clauseList.size();
    for (int i = 0; i < size; ++i) {
        Clause cl = clauseList.get(i);
        if (cl.getClauseType() != ClauseType.LET_CLAUSE) {
            break;
        }
        boolean hasConsequentLet = false;
        if (i < size - 1) {
            Clause nextCl = clauseList.get(i + 1);
            hasConsequentLet = nextCl.getClauseType() == ClauseType.LET_CLAUSE;
        }
        visitLetClause((LetClause) cl, step, firstLet, hasConsequentLet);
        firstLet = false;
        processedLetList.add(cl);
    }
    clauseList.removeAll(processedLetList);
}