public static Expression convert()

in spark/v3.4/spark/src/main/java/org/apache/iceberg/spark/SparkV2Filters.java [127:310]
156 lines of code
59 McCabe index (conditional complexity)

  public static Expression convert(Predicate predicate) {
    Operation op = FILTERS.get(predicate.name());
    if (op != null) {
      switch (op) {
        case TRUE:
          return Expressions.alwaysTrue();

        case FALSE:
          return Expressions.alwaysFalse();

        case IS_NULL:
          if (canConvertToTerm(child(predicate))) {
            UnboundTerm<Object> term = toTerm(child(predicate));
            return term != null ? isNull(term) : null;
          }

          return null;

        case NOT_NULL:
          if (canConvertToTerm(child(predicate))) {
            UnboundTerm<Object> term = toTerm(child(predicate));
            return term != null ? notNull(term) : null;
          }

          return null;

        case LT:
          if (canConvertToTerm(leftChild(predicate)) && isLiteral(rightChild(predicate))) {
            UnboundTerm<Object> term = toTerm(leftChild(predicate));
            return term != null ? lessThan(term, convertLiteral(rightChild(predicate))) : null;
          } else if (canConvertToTerm(rightChild(predicate)) && isLiteral(leftChild(predicate))) {
            UnboundTerm<Object> term = toTerm(rightChild(predicate));
            return term != null ? greaterThan(term, convertLiteral(leftChild(predicate))) : null;
          } else {
            return null;
          }

        case LT_EQ:
          if (canConvertToTerm(leftChild(predicate)) && isLiteral(rightChild(predicate))) {
            UnboundTerm<Object> term = toTerm(leftChild(predicate));
            return term != null
                ? lessThanOrEqual(term, convertLiteral(rightChild(predicate)))
                : null;
          } else if (canConvertToTerm(rightChild(predicate)) && isLiteral(leftChild(predicate))) {
            UnboundTerm<Object> term = toTerm(rightChild(predicate));
            return term != null
                ? greaterThanOrEqual(term, convertLiteral(leftChild(predicate)))
                : null;
          } else {
            return null;
          }

        case GT:
          if (canConvertToTerm(leftChild(predicate)) && isLiteral(rightChild(predicate))) {
            UnboundTerm<Object> term = toTerm(leftChild(predicate));
            return term != null ? greaterThan(term, convertLiteral(rightChild(predicate))) : null;
          } else if (canConvertToTerm(rightChild(predicate)) && isLiteral(leftChild(predicate))) {
            UnboundTerm<Object> term = toTerm(rightChild(predicate));
            return term != null ? lessThan(term, convertLiteral(leftChild(predicate))) : null;
          } else {
            return null;
          }

        case GT_EQ:
          if (canConvertToTerm(leftChild(predicate)) && isLiteral(rightChild(predicate))) {
            UnboundTerm<Object> term = toTerm(leftChild(predicate));
            return term != null
                ? greaterThanOrEqual(term, convertLiteral(rightChild(predicate)))
                : null;
          } else if (canConvertToTerm(rightChild(predicate)) && isLiteral(leftChild(predicate))) {
            UnboundTerm<Object> term = toTerm(rightChild(predicate));
            return term != null
                ? lessThanOrEqual(term, convertLiteral(leftChild(predicate)))
                : null;
          } else {
            return null;
          }

        case EQ: // used for both eq and null-safe-eq
          Pair<UnboundTerm<Object>, Object> eqChildren = predicateChildren(predicate);
          if (eqChildren == null) {
            return null;
          }

          if (predicate.name().equals(EQ)) {
            // comparison with null in normal equality is always null. this is probably a mistake.
            Preconditions.checkNotNull(
                eqChildren.second(),
                "Expression is always false (eq is not null-safe): %s",
                predicate);
          }

          return handleEqual(eqChildren.first(), eqChildren.second());

        case NOT_EQ:
          Pair<UnboundTerm<Object>, Object> notEqChildren = predicateChildren(predicate);
          if (notEqChildren == null) {
            return null;
          }

          // comparison with null in normal equality is always null. this is probably a mistake.
          Preconditions.checkNotNull(
              notEqChildren.second(),
              "Expression is always false (notEq is not null-safe): %s",
              predicate);

          return handleNotEqual(notEqChildren.first(), notEqChildren.second());

        case IN:
          if (isSupportedInPredicate(predicate)) {
            UnboundTerm<Object> term = toTerm(childAtIndex(predicate, 0));

            return term != null
                ? in(
                    term,
                    Arrays.stream(predicate.children())
                        .skip(1)
                        .map(val -> convertLiteral(((Literal<?>) val)))
                        .filter(Objects::nonNull)
                        .collect(Collectors.toList()))
                : null;
          } else {
            return null;
          }

        case NOT:
          Not notPredicate = (Not) predicate;
          Predicate childPredicate = notPredicate.child();
          if (childPredicate.name().equals(IN) && isSupportedInPredicate(childPredicate)) {
            UnboundTerm<Object> term = toTerm(childAtIndex(childPredicate, 0));
            if (term == null) {
              return null;
            }

            // infer an extra notNull predicate for Spark NOT IN filters
            // as Iceberg expressions don't follow the 3-value SQL boolean logic
            // col NOT IN (1, 2) in Spark is equal to notNull(col) && notIn(col, 1, 2) in Iceberg
            Expression notIn =
                notIn(
                    term,
                    Arrays.stream(childPredicate.children())
                        .skip(1)
                        .map(val -> convertLiteral(((Literal<?>) val)))
                        .filter(Objects::nonNull)
                        .collect(Collectors.toList()));
            return and(notNull(term), notIn);
          } else if (hasNoInFilter(childPredicate)) {
            Expression child = convert(childPredicate);
            if (child != null) {
              return not(child);
            }
          }
          return null;

        case AND:
          {
            And andPredicate = (And) predicate;
            Expression left = convert(andPredicate.left());
            Expression right = convert(andPredicate.right());
            if (left != null && right != null) {
              return and(left, right);
            }
            return null;
          }

        case OR:
          {
            Or orPredicate = (Or) predicate;
            Expression left = convert(orPredicate.left());
            Expression right = convert(orPredicate.right());
            if (left != null && right != null) {
              return or(left, right);
            }
            return null;
          }

        case STARTS_WITH:
          String colName = SparkUtil.toColumnName(leftChild(predicate));
          return startsWith(colName, convertLiteral(rightChild(predicate)).toString());
      }
    }

    return null;
  }