com.sap.cds.jdbc.generic.UnfoldIsOperatorModifier Maven / Gradle / Ivy
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package com.sap.cds.jdbc.generic;
import static com.sap.cds.impl.builder.model.ComparisonPredicate.eq;
import static com.sap.cds.impl.builder.model.ComparisonPredicate.ne;
import static com.sap.cds.ql.CQL.and;
import static com.sap.cds.ql.CQL.or;
import com.sap.cds.ql.CQL;
import com.sap.cds.ql.Value;
import com.sap.cds.ql.cqn.CqnComparisonPredicate.Operator;
import com.sap.cds.ql.cqn.CqnPredicate;
import com.sap.cds.ql.cqn.Modifier;
public class UnfoldIsOperatorModifier implements Modifier {
@Override
public CqnPredicate comparison(Value lhs, Operator op, Value rhs) {
switch (op) {
case IS:
// (a = b AND a IS NOT NULL AND b IS NOT NULL) OR (a IS NULL AND b IS NULL)
CqnPredicate bothNotNull = and(lhs.isNotNull(), rhs.isNotNull());
CqnPredicate bothNull = and(lhs.isNull(), rhs.isNull());
return or(and(eq(lhs, rhs), bothNotNull), bothNull);
case IS_NOT:
// ((a <> b OR a IS NULL OR b IS NULL) AND (a IS NOT NULL OR b IS NOT NULL))
CqnPredicate eitherNull = or(lhs.isNull(), rhs.isNull());
CqnPredicate eitherNotNull = or(lhs.isNotNull(), rhs.isNotNull());
return and(or(ne(lhs, rhs), eitherNull), eitherNotNull);
default:
return CQL.comparison(lhs, op, rhs);
}
}
}