Package org.apache.solr.analytics.function.mapping

Class LambdaFunction

  • public class LambdaFunction
extends Object
    Lambda Functions are used to easily create basic mapping functions.

    There are lambda functions for all types: boolean, int, long, float, double, date and string. Lambda functions must have parameters of all the same type, which will be the same type as the returned Value or ValueStream.

    The types of functions that are accepted are: (multi = multi-valued expression, single = single-valued expression)

    • func(single) -> single
    • func(multi) -> multi
    • func(single,single) -> single
    • func(multi,single) -> multi
    • func(single,multi) -> multi
    • func(multi) -> single
    • func(single,single,...) -> single (You can also specify whether all parameters must exist, or at least one must exist for the returned value to exist)

    NOTE: The combination of name and parameters MUST be unique for an expression.
    For example consider if join(fieldA, ',') and join(fieldA, ';') are both called. If the JoinFunction uses:
    LambdaFunction.createStringLambdaFunction("join", (a,b) -> a + sep + b, (StringValueStream)params[0])
    then both the name "join" and single parameter fieldA will be used for two DIFFERENT expressions. This does not meet the uniqueness requirmenet and will break the query.
    A solution to this is to name the function using the missing information:
    LambdaFunction.createStringLambdaFunction("join(" + sep + ")", (a,b) -> a + sep + b, (StringValueStream)params[0])
    Therefore both expressions will have fieldA as the only parameter, but the names "join(,)" and "join(;)" will be different. This meets the uniqueness requirement for lambda functions.

    • Constructor Detail

      • LambdaFunction

        public LambdaFunction()

    • Method Detail

      • createBooleanLambdaFunction

        public static BooleanValueStream createBooleanLambdaFunction​(String name,
                                                             LambdaFunction.BoolInBoolOutLambda lambda,
                                                             BooleanValueStream param)
        Creates a function that takes in either a single or multi valued boolean expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (boolean) -> boolean
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createBooleanLambdaFunction

        public static BooleanValue createBooleanLambdaFunction​(String name,
                                                       LambdaFunction.TwoBoolInBoolOutLambda lambda,
                                                       BooleanValueStream param)
        Creates a function that takes in a multi-valued boolean expression and returns a single-valued boolean expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (boolean, boolean) -> boolean
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createBooleanLambdaFunction

        public static BooleanValueStream createBooleanLambdaFunction​(String name,
                                                             LambdaFunction.TwoBoolInBoolOutLambda lambda,
                                                             BooleanValueStream param1,
                                                             BooleanValueStream param2)
                                                      throws SolrException
        Creates a function that maps two booleans to a single boolean. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (boolean,boolean) -> boolean
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createBooleanLambdaFunction

        public static BooleanValue createBooleanLambdaFunction​(String name,
                                                       LambdaFunction.TwoBoolInBoolOutLambda lambda,
                                                       BooleanValue[] params,
                                                       boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value boolean expressions into a single-value boolean expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (boolean, boolean) -> boolean
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createIntLambdaFunction

        public static IntValueStream createIntLambdaFunction​(String name,
                                                     LambdaFunction.IntInIntOutLambda lambda,
                                                     IntValueStream param)
        Creates a function that takes in either a single or multi valued integer expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (integer) -> integer
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createIntLambdaFunction

        public static IntValue createIntLambdaFunction​(String name,
                                               LambdaFunction.TwoIntInIntOutLambda lambda,
                                               IntValueStream param)
        Creates a function that takes in a multi-valued integer expression and returns a single-valued integer expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (integer, integer) -> integer
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createIntLambdaFunction

        public static IntValueStream createIntLambdaFunction​(String name,
                                                     LambdaFunction.TwoIntInIntOutLambda lambda,
                                                     IntValueStream param1,
                                                     IntValueStream param2)
                                              throws SolrException
        Creates a function that maps two integers to a single integer. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (integer,integer) -> integer
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createIntLambdaFunction

        public static IntValue createIntLambdaFunction​(String name,
                                               LambdaFunction.TwoIntInIntOutLambda lambda,
                                               IntValue[] params,
                                               boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value integer expressions into a single-value integer expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (integer, integer) -> integer
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createLongLambdaFunction

        public static LongValueStream createLongLambdaFunction​(String name,
                                                       LambdaFunction.LongInLongOutLambda lambda,
                                                       LongValueStream param)
        Creates a function that takes in either a single or multi valued long expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (long) -> long
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createLongLambdaFunction

        public static LongValue createLongLambdaFunction​(String name,
                                                 LambdaFunction.TwoLongInLongOutLambda lambda,
                                                 LongValueStream param)
        Creates a function that takes in a multi-valued long expression and returns a single-valued long expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (boolean, boolean) -> boolean
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createLongLambdaFunction

        public static LongValueStream createLongLambdaFunction​(String name,
                                                       LambdaFunction.TwoLongInLongOutLambda lambda,
                                                       LongValueStream param1,
                                                       LongValueStream param2)
                                                throws SolrException
        Creates a function that maps two longs to a single long. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (long,long) -> long
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createLongLambdaFunction

        public static LongValue createLongLambdaFunction​(String name,
                                                 LambdaFunction.TwoLongInLongOutLambda lambda,
                                                 LongValue[] params,
                                                 boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value long expressions into a single-value long expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (long, long) -> long
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createFloatLambdaFunction

        public static FloatValueStream createFloatLambdaFunction​(String name,
                                                         LambdaFunction.FloatInFloatOutLambda lambda,
                                                         FloatValueStream param)
        Creates a function that takes in either a single or multi valued float expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (float) -> float
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createFloatLambdaFunction

        public static FloatValue createFloatLambdaFunction​(String name,
                                                   LambdaFunction.TwoFloatInFloatOutLambda lambda,
                                                   FloatValueStream param)
        Creates a function that takes in a multi-valued float expression and returns a single-valued float expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (float, float) -> float
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createFloatLambdaFunction

        public static FloatValueStream createFloatLambdaFunction​(String name,
                                                         LambdaFunction.TwoFloatInFloatOutLambda lambda,
                                                         FloatValueStream param1,
                                                         FloatValueStream param2)
                                                  throws SolrException
        Creates a function that maps two floats to a single float. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (float,float) -> float
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createFloatLambdaFunction

        public static FloatValue createFloatLambdaFunction​(String name,
                                                   LambdaFunction.TwoFloatInFloatOutLambda lambda,
                                                   FloatValue[] params,
                                                   boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value float expressions into a single-value float expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (float, float) -> float
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createDoubleLambdaFunction

        public static DoubleValueStream createDoubleLambdaFunction​(String name,
                                                           LambdaFunction.DoubleInDoubleOutLambda lambda,
                                                           DoubleValueStream param)
        Creates a function that takes in either a single or multi valued double expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (double) -> double
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createDoubleLambdaFunction

        public static DoubleValue createDoubleLambdaFunction​(String name,
                                                     LambdaFunction.TwoDoubleInDoubleOutLambda lambda,
                                                     DoubleValueStream param)
        Creates a function that takes in a multi-valued double expression and returns a single-valued double expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (double, double) -> double
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createDoubleLambdaFunction

        public static DoubleValueStream createDoubleLambdaFunction​(String name,
                                                           LambdaFunction.TwoDoubleInDoubleOutLambda lambda,
                                                           DoubleValueStream param1,
                                                           DoubleValueStream param2)
                                                    throws SolrException
        Creates a function that maps two doubles to a single double. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (double,double) -> double
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createDoubleLambdaFunction

        public static DoubleValue createDoubleLambdaFunction​(String name,
                                                     LambdaFunction.TwoDoubleInDoubleOutLambda lambda,
                                                     DoubleValue[] params,
                                                     boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value double expressions into a single-value double expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (double, double) -> double
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createDateLambdaFunction

        public static DateValueStream createDateLambdaFunction​(String name,
                                                       LambdaFunction.LongInLongOutLambda lambda,
                                                       DateValueStream param)
        Creates a function that takes in either a single or multi valued date expression and returns the same type of expression with the given lambda function applied to every value.

        NOTE: The lambda must work on longs, not Date objects

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (long) -> long
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createDateLambdaFunction

        public static DateValue createDateLambdaFunction​(String name,
                                                 LambdaFunction.TwoLongInLongOutLambda lambda,
                                                 DateValueStream param)
        Creates a function that takes in a multi-valued date expression and returns a single-valued date expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.

        NOTE: The lambda must work on longs, not Date objects

        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (long, long) -> long
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createDateLambdaFunction

        public static DateValueStream createDateLambdaFunction​(String name,
                                                       LambdaFunction.TwoLongInLongOutLambda lambda,
                                                       DateValueStream param1,
                                                       DateValueStream param2)
                                                throws SolrException
        Creates a function that maps two dates to a single date. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        NOTE: The lambda must work on longs, not Date objects

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (long,long) -> long
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createDateLambdaFunction

        public static DateValue createDateLambdaFunction​(String name,
                                                 LambdaFunction.TwoLongInLongOutLambda lambda,
                                                 DateValue[] params,
                                                 boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value date expressions into a single-value date expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.

        NOTE: The lambda must work on longs, not Date objects

        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (long, long) -> long
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda

      • createStringLambdaFunction

        public static StringValueStream createStringLambdaFunction​(String name,
                                                           LambdaFunction.StringInStringOutLambda lambda,
                                                           StringValueStream param)
        Creates a function that takes in either a single or multi valued string expression and returns the same type of expression with the given lambda function applied to every value.
        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (String) -> String
        param - the expression to apply the lambda to
        Returns:
        an expression the same type as was given with the lambda applied

      • createStringLambdaFunction

        public static StringValue createStringLambdaFunction​(String name,
                                                     LambdaFunction.TwoStringInStringOutLambda lambda,
                                                     StringValueStream param)
        Creates a function that takes in a multi-valued string expression and returns a single-valued string expression. The given lambda is used to associatively (order not guaranteed) reduce all values for a document down to a single value.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (String, String) -> String
        param - the expression to be reduced per-document
        Returns:
        a single-valued expression which has been reduced for every document

      • createStringLambdaFunction

        public static StringValueStream createStringLambdaFunction​(String name,
                                                           LambdaFunction.TwoStringInStringOutLambda lambda,
                                                           StringValueStream param1,
                                                           StringValueStream param2)
                                                    throws SolrException
        Creates a function that maps two strings to a single string. This can take the following shapes:
        • Taking in two single-valued expressions and returning a single-valued expression which represents the lambda combination of the inputs.
        • Taking in a single-valued expression and a multi-valued expression and returning a multi-valued expression which represents the lambda combination of the single-value input with each of the values of the multi-value input.
          The inputs can be either func(single,multi) or func(multi,single).

        Parameters:
        name - name for the function
        lambda - the function to be applied to every value: (String,String) -> String
        param1 - the first parameter in the lambda
        param2 - the second parameter in the lambda
        Returns:
        a single or multi valued expression combining the two parameters with the given lambda
        Throws:
        SolrException - if neither parameter is single-valued

      • createStringLambdaFunction

        public static StringValue createStringLambdaFunction​(String name,
                                                     LambdaFunction.TwoStringInStringOutLambda lambda,
                                                     StringValue[] params,
                                                     boolean allMustExist)
        Creates a function that associatively (order is guaranteed) reduces multiple single-value string expressions into a single-value string expression for each document.
        For a document, every parameter's value must exist for the resulting value to exist if allMustExist is true. If allMustExist is false, only one of the parameters' values must exist.
        Parameters:
        name - name for the function
        lambda - the associative function used to reduce the values: (String, String) -> String
        params - the expressions to reduce
        allMustExist - whether all parameters are required to exist
        Returns:
        a single-value expression that reduces the parameters with the given lambda