Module datarush.library
Package com.pervasive.datarush.functions

Class Predicates

  • public class Predicates
extends Object
    Provides implementations of common boolean and logical functions. These functions can also be combined to construct more complex predicates.

    Most predicate functions follow three-valued logic (true, false, null) except where otherwise noted.

    See Also:
    ScalarValuedFunction, DeriveFields, FilterRows

    • Constructor Detail

      • Predicates

        public Predicates()

    • Method Detail

      • isConjunction

        public static boolean isConjunction​(ScalarValuedFunction f)
        Tests whether the specified function is an AND predicate.
        Parameters:
        f - the function to test
        Returns:
        true if the function is an AND; false otherwise
        See Also:
        and(ScalarValuedFunction...)

      • isDisjunction

        public static boolean isDisjunction​(ScalarValuedFunction f)
        Tests whether the specified function is an OR predicate.
        Parameters:
        f - the function to test
        Returns:
        true if the function is an OR; false otherwise
        See Also:
        or(ScalarValuedFunction...)

      • and

        public static ScalarValuedFunction and​(ScalarValuedFunction... ps)
        Builds a record predicate which is a logical and of the specified predicates. The resulting predicate evaluates to:
        • true if all subpredicates evaluate to true.
        • false if any subpredicate evaluates to false.
        • null otherwise

        This version of and is provided for use in a fluent style with other static methods producing RecordPredicate objects, as illustrated by the following code fragment:
        and(eq("field1", "field2"),gt("field1","field3"))

        Parameters:
        ps - the predicates to be combined
        Returns:
        a new predicate evaluating to an and of the predicates under three-valued logic

      • and

        public static ScalarValuedFunction and​(List<ScalarValuedFunction> ps)
        Builds a record predicate which is a logical and of the specified predicates. The resulting predicate evaluates to:
        • true if all subpredicates evaluate to true.
        • false if any subpredicate evaluates to false.
        • null otherwise
        Parameters:
        ps - the predicates to be combined
        Returns:
        a new predicate evaluating to an and of the predicates under three-valued logic

      • or

        public static ScalarValuedFunction or​(ScalarValuedFunction... ps)
        Builds a record predicate which is a logical or of the specified predicates. The resulting predicate evaluates to
        • true if any subpredicate evaluates to true.
        • false if all subpredicates evaluate to false.
        • null otherwise

        This version of or is provided for use in a fluent style with other static methods producing RecordPredicate objects, as illustrated by the following code fragment:
        or(eq("field1", "field2"),gt("field1","field3"))

        Parameters:
        ps - the predicates to be combined
        Returns:
        a new predicate evaluating to an or of the predicates under three-valued logic

      • or

        public static ScalarValuedFunction or​(List<ScalarValuedFunction> ps)
        Builds a record predicate which is a logical or of the specified predicates. The resulting predicate evaluates to
        • true if any subpredicate evaluates to true.
        • false if all subpredicates evaluate to false.
        • null otherwise
        Parameters:
        ps - the predicates to be combined
        Returns:
        a new predicate evaluating to an or of the predicates under three-valued logic

      • not

        public static ScalarValuedFunction not​(ScalarValuedFunction p)
        Builds a record predicate which is a logical negation of specified predicate. The resulting predicate evaluates to
        • true if the given predicate evaluates to false.
        • false if the given predicate evaluates to true.
        • null otherwise
        Parameters:
        p - the predicates to be negated
        Returns:
        a new predicate evaluating to a negation of the predicate under three-valued logic

      • isTrue

        public static ScalarValuedFunction isTrue​(ScalarValuedFunction p)
        Builds a record predicate which tests whether the specified predicate is true. The resulting predicate evaluates to
        • true if the given predicate evaluates to true.
        • false otherwise
        Parameters:
        p - the predicate to be tested
        Returns:
        a new predicate evaluating to a check of the truth of the predicate

      • notTrue

        public static ScalarValuedFunction notTrue​(ScalarValuedFunction p)
        Builds a record predicate which tests whether the specified predicate is not true. The resulting predicate evaluates to
        • false if the given predicate evaluates to true.
        • true otherwise
        Parameters:
        p - the predicate to be tested
        Returns:
        a new predicate evaluating to a check of the non-truth of the predicate

      • isFalse

        public static ScalarValuedFunction isFalse​(ScalarValuedFunction p)
        Builds a record predicate which tests whether the specified predicate is false. The resulting predicate evaluates to
        • true if the given predicate evaluates to false.
        • false otherwise
        Parameters:
        p - the predicate to be tested
        Returns:
        a new predicate evaluating to a check of the falsity of the predicate

      • notFalse

        public static ScalarValuedFunction notFalse​(ScalarValuedFunction p)
        Builds a record predicate which tests whether the specified predicate is not false. The resulting predicate evaluates to
        • false if the given predicate evaluates to false.
        • true otherwise
        Parameters:
        p - the predicate to be tested
        Returns:
        a new predicate evaluating to a check of the non-falsity of the predicate

      • eq

        public static ScalarValuedFunction eq​(String leftField,
                                      String rightField)
        Builds a record predicate which tests the equality of the specified fields. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the first record field value in the comparison
        rightField - the second record field value in the comparison
        Returns:
        a function evaluating the predicate

      • eq

        public static ScalarValuedFunction eq​(String field,
                                      ScalarValued value)
        Builds a record predicate which tests the equality of the specified field with a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        field - the record field value in the comparison
        value - the known value in the comparison
        Returns:
        a function evaluating the predicate

      • eq

        public static ScalarValuedFunction eq​(ScalarValuedFunction leftExpr,
                                      ScalarValuedFunction rightExpr)
        Builds a record predicate which tests the equality of the specified expressions. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • neq

        public static ScalarValuedFunction neq​(String leftField,
                                       String rightField)
        Builds a record predicate which tests the inequality of the specified fields. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the first record field value in the comparison
        rightField - the second record field value in the comparison
        Returns:
        a function evaluating the predicate

      • neq

        public static ScalarValuedFunction neq​(String field,
                                       ScalarValued value)
        Builds a record predicate which tests the inequality of the specified field with a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        field - the record field value in the comparison
        value - the known value in the comparison
        Returns:
        a function evaluating the predicate

      • neq

        public static ScalarValuedFunction neq​(ScalarValuedFunction leftExpr,
                                       ScalarValuedFunction rightExpr)
        Builds a record predicate which tests the inequality of the specified expressions. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • lt

        public static ScalarValuedFunction lt​(String leftField,
                                      String rightField)
        Builds a record predicate which tests whether a field is strictly less than another field. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightField - the record field value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • lt

        public static ScalarValuedFunction lt​(String leftField,
                                      ScalarValued rightValue)
        Builds a record predicate which tests whether a field is strictly less than a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightValue - the known value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • lt

        public static ScalarValuedFunction lt​(ScalarValuedFunction leftExpr,
                                      ScalarValuedFunction rightExpr)
        Builds a record predicate which tests whether a specified expression is strictly less than another. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • gt

        public static ScalarValuedFunction gt​(String leftField,
                                      String rightField)
        Builds a record predicate which tests whether a field is strictly greater than another field. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightField - the record field value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • gt

        public static ScalarValuedFunction gt​(String leftField,
                                      ScalarValued rightValue)
        Builds a record predicate which tests whether a field is strictly greater than a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightValue - the known value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • gt

        public static ScalarValuedFunction gt​(ScalarValuedFunction leftExpr,
                                      ScalarValuedFunction rightExpr)
        Builds a record predicate which tests whether a specified expression is strictly greater than another. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • lte

        public static ScalarValuedFunction lte​(String leftField,
                                       String rightField)
        Builds a record predicate which tests whether a field is less than or equal to another field. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightField - the record field value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • lte

        public static ScalarValuedFunction lte​(String leftField,
                                       ScalarValued rightValue)
        Builds a record predicate which tests whether a field is less than or equal to a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightValue - the known value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • lte

        public static ScalarValuedFunction lte​(ScalarValuedFunction leftExpr,
                                       ScalarValuedFunction rightExpr)
        Builds a record predicate which tests whether a specified expression is less than or equal to another. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • gte

        public static ScalarValuedFunction gte​(String leftField,
                                       String rightField)
        Builds a record predicate which tests whether a field is greater than or equal to another field. The fields must be of compatible types for comparison. If either field is null-valued, the predicate evaluates to null.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightField - the record field value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • gte

        public static ScalarValuedFunction gte​(String leftField,
                                       ScalarValued rightValue)
        Builds a record predicate which tests whether a field is greater than or equal to a known value. The field and value must be of compatible types for comparison. If either value evaluates to null, so does the predicate.
        Parameters:
        leftField - the record field value on the left side of the comparison
        rightValue - the known value on the right side of the comparison
        Returns:
        a function evaluating the predicate

      • gte

        public static ScalarValuedFunction gte​(ScalarValuedFunction leftExpr,
                                       ScalarValuedFunction rightExpr)
        Builds a record predicate which tests whether a specified expression is greater than or equal to another. The expressions must evaluate to compatible types for comparison. If either expression evaluates to null, so does the predicate.
        Parameters:
        leftExpr - the expression producing the left value in the comparison
        rightExpr - the expression producing the right value in the comparison
        Returns:
        a function evaluating the predicate

      • isNull

        public static ScalarValuedFunction isNull​(String field)
        Builds a record predicate which tests whether a record field is null-valued. This predicate never yields null.
        Parameters:
        field - the record field value to test
        Returns:
        a function evaluating the predicate

      • isNull

        public static ScalarValuedFunction isNull​(ScalarValuedFunction expr)
        Builds a record predicate which tests whether the specified expression evaluates to null. This predicate never yields null.
        Parameters:
        expr - the expression to test
        Returns:
        a function evaluating the predicate

      • notNull

        public static ScalarValuedFunction notNull​(String field)
        Builds a record predicate which tests whether a record field is not null-valued. This predicate never yields null.
        Parameters:
        field - the record field value to test
        Returns:
        a function evaluating the predicate

      • notNull

        public static ScalarValuedFunction notNull​(ScalarValuedFunction expr)
        Builds a record predicate which tests whether the specified expression does not evaluate to null. This predicate never yields null.
        Parameters:
        expr - the expression to test
        Returns:
        a function evaluating the predicate

      • like

        public static ScalarValuedFunction like​(String field,
                                        String pattern)
        Builds a record predicate which tests whether the value of a field matches a specified SQL LIKE pattern. The field must contain a string value. If the field evaluates to null, so does the predicate.
        Parameters:
        field - the record field against which to match
        pattern - the string pattern to match
        Returns:
        a function evaluating the predicate

      • like

        public static ScalarValuedFunction like​(ScalarValuedFunction expr,
                                        String pattern)
        Builds a record predicate which tests whether the value of an expression matches a specified SQL LIKE pattern. The expression must evaluate to a string value. If the expression evaluates to null, so does the predicate.
        Parameters:
        expr - the expression to evaluate for the match operation
        pattern - the string pattern to match
        Returns:
        a function evaluating the predicate

      • likeToRegex

        public static String likeToRegex​(String likePattern)
        Converts a SQL LIKE pattern into an equivalent regular expression. Essentially the following transformation is made:
        • % is converted to .*
        • _ is converted to .
        • character ranges are preserved as is, excepting that negated ranges convert the initial ! to a ^
        Parameters:
        likePattern - the pattern match for the LIKE operation
        Returns:
        an equivalent regular expression

      • matches

        public static ScalarValuedFunction matches​(String field,
                                           String pattern)
        Builds a record predicate which tests whether the value of a field matches a specified regular expression. The field must contain a string value. If the field evaluates to null, so does the predicate.
        Parameters:
        field - the record field against which to match
        pattern - the string pattern to match
        Returns:
        a function evaluating the predicate

      • matches

        public static ScalarValuedFunction matches​(ScalarValuedFunction expr,
                                           String pattern)
        Builds a record predicate which tests whether the value of an expression matches a specified regular expression. The expression must evaluate to a string value. If the expression evaluates to null, so does the predicate.
        Parameters:
        expr - the expression to evaluate for the match operation
        pattern - the string pattern to match
        Returns:
        a function evaluating the predicate