Description: The not function returns the negation of the Boolean value of the subject.

Subject Type: Boolean

Arguments: No arguments

Return Type: Boolean

Examples: We can invert the value of another function by using the not function, as ${filename:equals('hello.txt'):not()}. This will return true if the filename is NOT equal to "hello.txt" and will return false if the filename is "hello.txt."

Description: Evaluates the first argument if the Subject evaluates to true, or the second argument if the Subject evaluates to false.

Subject Type: Boolean

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", the "nullFilename" attribute has the value null, and the "bool" attribute has the value "true", then the following expressions will provide the following results:

${nullFilename:isNull():ifElse('file does not exist', 'located file')}

file does not exist

${nullFilename:ifElse('found', 'not_found')}

not_found

${filename:ifElse('found', 'not_found')}

not_found

${filename:isNull():not():ifElse('found', 'not_found')}

found

Description: [.description]#The isJson function returns true if the subject is a JSON array or a JSON object, false otherwise. This is typically used to determine whether an attribute is JSON in order to allow for a follow-on JSONPath query. Although technically there are other valid JSON types such as string, number, boolean and null, this method is only concerned with the primary JSON objects queried with JSONPath , arrays and objects. #

Subject Type: Any

Arguments: No arguments

Return Type: Boolean

Examples: If the attribute "jsonObj" has the value {"name":"John", "age":30, "car":null}, the attribute jsonObjMissingStartingBrace has the value "name":"John", "age":30, "car":null}, the attribute jsonObjMissingEndingBrace has the value {"name":"John", "age":30, "car":null, the attribute "jsonArray" has the value ["Ford", "BMW", "Fiat"], the attribute jsonArrayMissingStartingBracket has the value "Ford", "BMW", "Fiat"], the attribute jsonArrayMissingEndingBracket has the value ["Ford", "BMW", "Fiat", the "someAttribute" attribute does not exist, the "emptyQuotedString" attribute value is "", the attribute "quotedString" has the value "someString", the attribute "integer" has the value 1234, the attribute "decimal" has the value 18.36, the attribute "trueAttr" has the value true, the attribute "falseAttr" has the value false and the "nullAttr" attribute has the value null, then the following expressions will provide the following results:

Description: This function converts the Subject into an all upper-case String. Said another way, it replaces any lowercase letter with the uppercase equivalent.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "filename" attribute is "abc123.txt", then the Expression ${filename:toUpper()} will return "ABC123.TXT"

Description: This function converts the Subject into an all lower-case String. Said another way, it replaces any uppercase letter with the lowercase equivalent.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "filename" attribute is "ABC123.TXT", then the Expression ${filename:toLower()} will return "abc123.txt"

Description: The trim function will remove any leading or trailing white space from its subject.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the attribute attr has the value " 1 2 3 ", then the Expression ${attr:trim()} will return the value "1 2 3".

Description: Returns a portion of the Subject, given a starting index and an optional ending index. If the ending index is not supplied, it will return the portion of the Subject starting at the given 'start index' and ending at the end of the Subject value.

The starting index and ending index are zero-based. That is, the first character is referenced by using the value 0, not 1.

If either the starting index is or the ending index is not a number, this function call will result in an error.

If the starting index is larger than the ending index, this function call will result in an error.

If the starting index or the ending index is greater than the length of the Subject or has a value less than 0, this function call will return an empty string.

Subject Type: String

Arguments:

If we have an attribute named "filename" with the value "a brand new filename.txt", then the following Expressions will result in the following values:

Description: Returns a portion of the Subject, starting with the first character of the Subject and ending with the character immediately before the first occurrence of the argument. If the argument is not present in the Subject, the entire Subject will be returned.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will result in the following values:

Description: Returns a portion of the Subject, starting with the first character of the Subject and ending with the character immediately before the last occurrence of the argument. If the argument is not present in the Subject, the entire Subject will be returned.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will result in the following values:

Description: Returns a portion of the Subject, starting with the character immediately after the first occurrence of the argument and extending to the end of the Subject. If the argument is not present in the Subject, the entire Subject will be returned.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will result in the following values:

Description: Returns a portion of the Subject, starting with the character immediately after the last occurrence of the argument and extending to the end of the Subject. If the argument is not present in the Subject, the entire Subject will be returned.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will result in the following values:

Description: Parses the Subject as a delimited line of text and returns just a single field from that delimited text.

Subject Type: String

Arguments:

index : The index of the field to return. A value of 1 will return the first field, a value of 2 will return the second field, and so on.

delimiter : Optional argument that provides the character to use as a field separator. If not specified, a comma will be used. This value must be exactly 1 character.

quoteChar : Optional argument that provides the character that can be used to quote values so that the delimiter can be used within a single field. If not specified, a double-quote (") will be used. This value must be exactly 1 character.

escapeChar : Optional argument that provides the character that can be used to escape the Quote Character or the Delimiter within a field. If not specified, a backslash (\) is used. This value must be exactly 1 character.

stripChars : Optional argument that specifies whether or not quote characters and escape characters should be stripped. For example, if we have a field value "1, 2, 3" and this value is true, we will get the value 1, 2, 3, but if this value is false, we will get the value "1, 2, 3" with the quotes. The default value is false. This value must be either true or false.

Examples: If the "line" attribute contains the value "Jacobson, John", 32, Mr. and the "altLine" attribute contains the value Jacobson, John|32|Mr. then the following Expressions will result in the following values:

Description: The append function returns the result of appending the argument to the value of the Subject. If the Subject is null, returns the argument itself.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the Expression ${filename:append('.gz')} will return "a brand new filename.txt.gz".

Description: The prepend function returns the result of prepending the argument to the value of the Subject. If the subject is null, returns the argument itself.

Subject Type: String

Arguments:

Description: Replaces all occurrences of one literal String within the Subject with another String.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: Replaces the first occurrence of one literal String or regular expression within the Subject with another String.

Subject Type: String

Arguments:

Search String : The String (literal or regular expression pattern) to find within the Subject

Replacement : The value to replace Search String with

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: The replaceAll function takes two String arguments: a literal String or Regular Expression (NiFi uses the Java Pattern syntax), and a replacement string. The return value is the result of substituting the replacement string for all patterns within the Subject that match the Regular Expression.

Subject Type: String

Arguments:

Replacement : The value to use for replacing matches in the Subject. If the regular expression argument uses Capturing Groups, back references are allowed in the replacement.

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: The padLeft function prepends the given padding string (or '_', if nothing is provided) to the argument String until the passed desired length is reached.

It returns the argument as is if its length is already equal or higher than the desired length, if the padding string is null, and if the desired length is either negative or greater than Integer.MAX_VALUE. It returns null if the argument string is not a valid attribute.

Subject Type: String

Arguments:

Examples: If the "greetings" attribute has the value "hello", then the following Expressions will provide the following results:

Description: The padRight function appends the given padding string (or '_', if nothing is provided) to the argument String until the passed desired length is reached.

It returns the argument as is if its length is already equal or higher than the desired length, if the padding string is null, and if the desired length is either negative or greater than Integer.MAX_VALUE. It returns null if the argument string is not a valid attribute.

Subject Type: String

Arguments:

Examples: If the "greetings" attribute has the value "hello", then the following Expressions will provide the following results:

Description: The replaceNull function returns the argument if the Subject is null. Otherwise, returns the Subject.

Subject Type: Any

Arguments:

Examples: If the attribute "filename" has the value "a brand new filename.txt" and the attribute "hello" does not exist, then the Expression ${filename:replaceNull('abc')} will return "a brand new filename.txt", while ${hello:replaceNull('abc')} will return "abc".

Description: The replaceEmpty function returns the argument if the Subject is null or if the Subject consists only of white space (new line, carriage return, tab, space). Otherwise, returns the Subject.

Subject Type: String

Arguments:

Examples: If the attribute "filename" has the value "a brand new filename.txt" and the attribute "hello" has the value " ", then the Expression ${filename:replaceEmpty('abc')} will return "a brand new filename.txt", while ${hello:replaceEmpty('abc')} will return "abc".

Description: Returns the length of the Subject

Subject Type: String

Arguments: No arguments

Return Type: Number

Examples: If the attribute "filename" has a value of "a brand new filename.txt" and the attribute "hello" does not exist, then the Expression ${filename:length()} will return 24. ${hello:length()} will return 0.

Description: This function evaluates the Expression Language inside the variable value.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If one of the registry variable named "query" has value "SELECT * FROM TABLE WHERE ID = ${id}" and the value of the "id" field, we are getting from the flowfile attributes (i.e. id=20) then the Expression ${query:evaluateELString()} will return SELECT * FROM TABLE WHERE ID = 20

Description: Returns a string that is the Subject repeated a random number of times between min repeats and max repeats. If max repeats is not supplied, it will return the Subject repeated exactly min repeats times.

The min repeats and max repeats must be positive numbers, with max repeats greater than or equal to min repeats

If either min repeats or max repeats is not a number, this function call will result in an error.

Subject Type: String

Arguments:

min repeats : The minimum number (inclusive) of times to repeat the subject, or the exact number of times to repeat the subject if max repeats is not supplied.

max repeats : The maximum number (inclusive) of times to repeat the subject.

If we have an attribute named "str" with the value "abc", then the following Expressions will result in the following values:

Each of the following functions will encode a string according the rules of the given data format.

Description: This function prepares the Subject to be inserted into JSON document by escaping the characters in the String using Json String rules. The function correctly escapes quotes and control-chars (tab, backslash, cr, ff, etc.)

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is 'He didn’t say, "Stop!"', then the Expression ${message:escapeJson()} will return 'He didn’t say, \"Stop!\"'

Description: This function prepares the Subject to be inserted into XML document by escaping the characters in a String using XML entities. The function correctly escapes quotes, apostrophe, ampersand, <, > and control-chars.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:escapeXml()} will return '"bread" & "butter"'

Description: This function prepares the Subject to be inserted into CSV document by escaping the characters in a String using the rules in RFC 4180. The function correctly escapes quotes and surround the string in quotes if needed.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is 'But finally, she left', then the Expression ${message:escapeCsv()} will return '"But finally, she left"'

Description: This function prepares the Subject to be inserted into HTML document by escaping the characters in a String using the HTML entities. Supports only the HTML 3.0 entities.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:escapeHtml3()} will return '"bread" & "butter"'

Description: This function prepares the Subject to be inserted into HTML document by escaping the characters in a String using the HTML entities. Supports all known HTML 4.0 entities.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:escapeHtml4()} will return '"bread" & "butter"'

Description: This function unescapes any Json literals found in the String.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is 'He didn’t say, \"Stop!\"', then the Expression ${message:unescapeJson()} will return 'He didn’t say, "Stop!"'

Description: This function unescapes a string containing XML entity escapes to a string containing the actual Unicode characters corresponding to the escapes. Supports only the five basic XML entities (gt, lt, quot, amp, apos).

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:unescapeXml()} will return '"bread" & "butter"'

Description: This function unescapes a String from a CSV document according to the rules of RFC 4180.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"But finally, she left"', then the Expression ${message:unescapeCsv()} will return 'But finally, she left'

Description: This function unescapes a string containing HTML 3 entity to a string containing the actual Unicode characters corresponding to the escapes. Supports only HTML 3.0 entities.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:unescapeHtml3()} will return '"bread" & "butter"'

Description: This function unescapes a string containing HTML 4 entity to a string containing the actual Unicode characters corresponding to the escapes. Supports all known HTML 4.0 entities.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If the "message" attribute is '"bread" & "butter"', then the Expression ${message:unescapeHtml4()} will return '"bread" & "butter"'

Description: Returns a URL-friendly version of the Subject. This is useful, for instance, when using an attribute value to indicate the URL of a website.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: We can URL-Encode an attribute named "url" by using the Expression ${url:urlEncode()}. If the value of the "url" attribute is "https://nifi.apache.org/some value with spaces", this Expression will then return "https%3A%2F%2Fnifi.apache.org%2Fsome+value+with+spaces".

Description: Converts a URL-friendly version of the Subject into a human-readable form.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If we have a URL-Encoded attribute named "url" with the value "https://nifi.apache.org/some%20value%20with%20spaces" or "https%3A%2F%2Fnifi.apache.org%2Fsome+value+with+spaces", then the Expression ${url:urlDecode()} will return "https://nifi.apache.org/some value with spaces".

Description: Returns a Base64 encoded string. This is useful for being able to transfer binary data as ascii.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: We can Base64-Encoded an attribute named "payload" by using the Expression ${payload:base64Encode()} If the attribute payload had a value of "admin:admin" then the Expression ${payload:base64Encode()} will return "YWRtaW46YWRtaW4=".

Description: Reverses the Base64 encoding on given string.

Subject Type: String

Arguments: No arguments

Return Type: String

Examples: If we have a Base64-Encoded attribute named "payload" with the value "YWRtaW46YWRtaW4=", then the Expression ${payload:base64Decode()} will return "admin:admin".

Description: Returns a type 3 (MD5 hashed) namespace name-based UUID. The argument must be a valid UUID.

Subject Type: String

Arguments:

Examples: If we have an attribute named "attr" with a value of "string value", then the Expression ${attr:UUID3('b9e81de3-7047-4b5e-a822-8fff5b49f808')} will return "bf0ea246-a177-3300-bd7e-d4c9e973dc6f".

An empty argument or an argument value with an invalid UUID results in an exception bulletin.

Description: Returns a type 5 (SHA-1 hashed) namespace name-based UUID. The argument must be a valid UUID.

Subject Type: String

Arguments:

Examples: If we have an attribute named "attr" with a value of "string value", then the Expression ${attr:UUID5('245b55a8-397d-4480-a41e-16603c8cf9ad')} will return "4d111477-5100-5f2d-ae79-b38bbe15aa78".

An empty argument or an argument value with an invalid UUID results in an exception bulletin.

Description: Returns true if the Subject starts with the String provided as the argument, false otherwise.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the Expression ${filename:startsWith('a brand')} will return true. ${filename:startsWith('A BRAND')} will return false. ${filename:toUpper():startsWith('A BRAND')} returns true.

Description: Returns true if the Subject ends with the String provided as the argument, false otherwise.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the Expression ${filename:endsWith('txt')} will return true. ${filename:endsWith('TXT')} will return false. ${filename:toUpper():endsWith('TXT')} returns true.

Description: Returns true if the Subject contains the value of the argument anywhere in the value.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the Expression ${filename:contains('new')} will return true. ${filename:contains('NEW')} will return false. ${filename:toUpper():contains('NEW')} returns true.

Description: Returns true if the Subject is matching one of the provided arguments.

Subject Type: String

Arguments:

Examples: If the "myEnum" attribute has the value "JOHN", then the Expression ${myEnum:in("PAUL", "JOHN", "MIKE")} will return true. ${myEnum:in("RED", "GREEN", "BLUE")} will return false.

Description: Returns true if the Subject contains any sequence of characters that matches the Regular Expression provided by the argument.

Subject Type: String

Arguments:

If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: Returns true if the Subject exactly matches the Regular Expression provided by the argument.

Subject Type: String

Arguments:

If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: Returns the index of the first character in the Subject that matches the String value provided as an argument. If the argument is found multiple times within the Subject, the value returned is the starting index of the first occurrence. If the argument cannot be found in the Subject, returns -1. The index is zero-based. This means that if the search string is found at the beginning of the Subject, the value returned will be 0, not 1.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: Returns the index of the first character in the Subject that matches the String value provided as an argument. If the argument is found multiple times within the Subject, the value returned is the starting index of the last occurrence. If the argument cannot be found in the Subject, returns -1. The index is zero-based. This means that if the search string is found at the beginning of the Subject, the value returned will be 0, not 1.

Subject Type: String

Arguments:

Examples: If the "filename" attribute has the value "a brand new filename.txt", then the following Expressions will provide the following results:

Description: The jsonPath function generates a string by evaluating the Subject as JSON and applying a JSON path expression. An empty string is generated if the Subject does not contain valid JSON, the jsonPath is invalid, or the path does not exist in the Subject. If the evaluation results in a scalar value, the string representation of scalar value is generated. Otherwise a string representation of the JSON result is generated. A JSON array of length 1 is special cased when [0] is a scalar, the string representation of [0] is generated.

Subject Type: String

Arguments: jsonPath : the JSON path expression used to evaluate the Subject.

Return Type: String

Examples: If the "myJson" attribute is

${myJson:jsonPath('$.phoneNumbers')}

[{"type":"home","number":"212 555-1234"},{"type":"office","number":"646 555-4567"}]

${myJson:jsonPath('$.missing-path')}

empty

${myJson:jsonPath('$.bad-json-path..')}

exception bulletin

Description: The jsonPathDelete function deletes the specified JsonPath from a Subject JSON and returns string form of the updated JSON.

Subject Type: String

Arguments: jsonPath : the JSON path expression to delete from the Subject.

Return Type: String

Examples: If the "myJson" attribute is

${myJson:jsonPathDelete('$.firstName')}

{"lastName":"Smith","age":25,"address":{"streetAddress":"21 2nd Street","city":"New York","state":"NY","postalCode":"10021-3100"},"phoneNumbers":[{"type":"home","number":"212 555-1234"},{"type":"office","number":"646 555-4567"}]}

${myJson:jsonPathDelete('$.missing-path')}

Returns original JSON document

Description: The jsonPathAdd function adds a scalar value to an array at the specified JsonPath on a Subject JSON and returns string form of the updated JSON. If the expression target element is a non-array, an empty string is returned and an exception is logged indicating the error. If the expression target element path is not in the JSON, the operation returns the original JSON without any modifications.

Subject Type: String

Arguments:

${myJson:jsonPathAdd('$.nicknames', 'Jimmy')}

{"firstName":"James", lastName":"Smith", "age":25, "voter":true, "height":6.1, "address":{"streetAddress":"21 2nd Street", "city":"New York", "state":"NY", "postalCode":"10021-3100"}, "phoneNumbers":[{"type":"home", "number":"212 555-1234"}, {"type":"office", "number":"646 555-4567"}],"nicknames":["Jimmy"]}

${myJson:jsonPathAdd('$.missingpath', 'Jimmy')}

Returns original JSON document with no modifications

${myJson:jsonPathAdd('$.firstName', 'Jimmy')}

empty

Description: The jsonPathSet function sets the value at the specified JsonPath on a Subject JSON and returns string form of the updated JSON.

Subject Type: String

Arguments:

${myJson:jsonPathSet('$.firstName', 'James')}

{"firstName":"James", lastName":"Smith", "age":25, "voter":true, "height":6.1, "address":{"streetAddress":"21 2nd Street", "city":"New York", "state":"NY", "postalCode":"10021-3100"}, "phoneNumbers":[{"type":"home", "number":"212 555-1234"}, {"type":"office", "number":"646 555-4567"}]}

${myJson:jsonPathSet('$.missingpath', 'James')}

Returns original JSON document

Description: The jsonPathPut function puts the key and scalar value at the specified JsonPath on a Subject JSON and returns string form of the updated JSON.

Subject Type: String

Arguments:

${myJson:jsonPathPut('$','middlename','Turon')}

{"firstName":"James", lastName":"Smith", "middlename": "Turon", "age":25, "voter":true, "height":6.1, "address":{"streetAddress":"21 2nd Street", "city":"New York", "state":"NY", "postalCode":"10021-3100"}, "phoneNumbers":[{"type":"home", "number":"212 555-1234"}, {"type":"office", "number":"646 555-4567"}]}

For those functions that support Decimal and Number (whole number) types, the return value type depends on the input types. If either the subject or argument are a Decimal then the result will be a Decimal. If both values are Numbers then the result will be a Number. This includes Divide. This is to preserve backwards compatibility and to not force rounding errors.

Description: Adds a numeric value to the Subject. If either the argument or the Subject cannot be coerced into a Number, returns null. Does not provide handling for overflow.

Subject Type: Number or Decimal

Arguments:

Examples: If the "fileSize" attribute has a value of 100, then the Expression ${fileSize:plus(1000)} will return the value 1100.

Description: Subtracts a numeric value from the Subject. Does not provide handling for overflow.

Subject Type: Number or Decimal

Arguments:

Examples: If the "fileSize" attribute has a value of 100, then the Expression ${fileSize:minus(100)} will return the value 0.

Description: Multiplies a numeric value by the Subject and returns the product. Does not provide handling for overflow.

Subject Type: Number or Decimal

Arguments:

Examples: If the "fileSize" attribute has a value of 100, then the Expression ${fileSize:multiply(1024)} will return the value 102400.

Description: Divides the Subject by a numeric value and returns the result.

Subject Type: Number or Decimal

Arguments:

Examples: If the "fileSize" attribute has a value of 100, then the Expression ${fileSize:divide(12)} will return the value 8.

Description: Performs a modular division of the Subject by the argument. That is, this function will divide the Subject by the value of the argument and return not the quotient but rather the remainder.

Subject Type: Number or Decimal

Arguments:

Examples: If the "fileSize" attribute has a value of 100, then the Expression ${fileSize:mod(12)} will return the value 4.

Description: Converts the Subject from a Base 10 number to a different Radix (or number base). An optional second argument can be used to indicate the minimum number of characters to be used. If the converted value has fewer than this number of characters, the number will be padded with leading zeroes. If a decimal is passed as the subject, it will first be converted to a whole number and then processed.

Subject Type: Number

Arguments:

Examples: If the "fileSize" attributes has a value of 1024, then the following Expressions will yield the following results:

Description: Converts the Subject from a specified Radix (or number base) to a base ten whole number. The subject will converted as is, without interpretation, and all characters must be valid for the base being converted from. For example converting "0xFF" from hex will not work due to "x" being a invalid hex character. If a decimal is passed as the subject, it will first be converted to a whole number and then processed.

Subject Type: String

Arguments:

Examples: If the "fileSize" attributes has a value of 1234A, then the following Expressions will yield the following results:

Description: Returns a random whole number ( 0 to 2^63 - 1) using an insecure random number generator.

Subject Type: No subject

Arguments: No arguments

Return Type: Number

Examples: ${random():mod(10):plus(1)} returns random number between 1 and 10 inclusive.

Description: Formats a number as a date/time according to the format specified by the argument. The argument must be a String that is a valid Java SimpleDateFormat format. The Subject is expected to be a Number that represents the number of milliseconds since Midnight GMT on January 1, 1970. The number will be evaluated using the local time zone unless specified in the second optional argument.

Subject Type: Number

Arguments:

Examples: If the attribute "time" has the value "1420058163264", then the following Expressions will yield the following results:

${time:format("yyyy/MM/dd HH:mm:ss.SSS'Z'", "America/Los_Angeles")}

2014/12/31 12:36:03.264Z

${time:format("yyyy/MM/dd HH:mm:ss.SSS'Z'", "Asia/Tokyo")}

2015/01/01 05:36:03.264Z

${time:format("yyyy/MM/dd", "GMT")}

2014/12/31

${time:format("HH:mm:ss.SSS'Z'", "GMT")}

20:36:03.264Z

${time:format("yyyy", "GMT")}

Description: [.description]#Formats an Instant, number or string according to the format specified by the argument.

The first argument must be a String that is a valid Java DateTimeFormatter format. The second argument must be a String that is a valid time zone. The Subject is expected to be an Instant, String or Number that represents the number of milliseconds since Midnight GMT on January 1, 1970 or a String with one of the following

DateTimeFormatter syntaxes:#

Examples: If the attribute "time" has the value "1647884009479", timeIsoOffset has the value "2022-12-03T10:15:30+01:00", timeIsoInstant has the value "2022-12-03T10:15:30Z" and "timeRFC1123" has the value "Thu, 01 Dec 2022 16:00:00 GMT", then the following Expressions will yield the following results:

${timeIsoOffset:formatInstant("yyyy/MM/dd HH:mm:ss.SSS'Z'", "Asia/Tokyo")}

2022/12/03 18:15:30.000Z

${timeIsoInstant:formatInstant("yyyy/MM/dd", "Asia/Tokyo")}

2022/12/03 19:15:30.000Z

${timeRFC1123:formatInstant("yyyy/MM/dd HH:mm:ss.SSS'Z'", "GMT")}

2022/12/01 16:00:00.000Z

Description: Converts a String into a Date data type, based on the format specified by the argument. The argument must be a String that is a valid Java SimpleDateFormat syntax. The Subject is expected to be a String that is formatted according the argument. The date will be evaluated using the local time zone unless specified in the second optional argument.

Subject Type: String

Arguments:

format : The current format to use when parsing the Subject, in the Java SimpleDateFormat syntax.

time zone : Optional argument that specifies the time zone to use when parsing the Subject, in the Java TimeZone syntax.

Examples: If the attribute "year" has the value "2014" and the attribute "time" has the value "2014/12/31 15:36:03.264Z", then the Expression ${year:toDate('yyyy', 'GMT')} will return a Date data type with a value representing Midnight GMT on January 1, 2014. The Expression ${time:toDate("yyyy/MM/dd HH:mm:ss.SSS’Z'", "GMT")} will result in a Date data type for 15:36:03.264 GMT on December 31, 2014.

Description: Converts a String or Number into an Instant data type, based on the format specified by the argument. In case of String format nanosecond precision date parsing is supported. The argument must be a String that is a valid Java DateTimeFormatter syntax. The Subject is expected to be a String that is formatted according the argument or a number which represents the datetime in milliseconds. The datetime will be evaluated using the time zone specified in the second argument.

Subject Type: String or Number

Arguments:

format : The current format to use when parsing the Subject, in the Java DateTimeFormatter syntax.

time zone : Required argument that specifies the time zone to use when parsing the Subject, in the Java TimeZone syntax.

Examples: If the attribute "time" has the value "2014/12/31 15:36:03.264Z" then the expression ${time:toInstant("yyyy/MM/dd HH:mm:ss.SSS’Z'", "GMT")} will result in an Instant data type for 15:36:03.264 GMT on December 31, 2014.

Description: Converts an Instant Subject into a Number with microsecond precision

Subject Type: Instant

Arguments: No arguments

Return Type: Number

Examples: If the "dateTime" attribute has the value of "2022/03/18 10:22:27.678234567", then the Expression ${dateTime:toInstant('yyyy/MM/dd HH:mm:ss.SSSSSSSSS', 'America/New_York'):toMicros()} converts the Instant value of the attribute to 1647613347678234 microseconds since epoch.

Description: Converts an Instant Subject into a Number with nanosecond precision

Subject Type: Instant

Arguments: No arguments

Return Type: Number

Examples: If the "dateTime" attribute has the value of "2022/03/18 10:22:27.678234567", then the Expression ${dateTime:toInstant('yyyy/MM/dd HH:mm:ss.SSSSSSSSS', 'America/New_York'):toNanos()} converts the Instant value of the attribute to 1647613347678234567 nanoseconds since epoch.

Description: Returns the current date and time as a Date data type object.

Subject Type: No Subject

Arguments: No arguments

Return Type: Date

Examples: We can get the current date and time as a Date data type by using the now function: ${now()}. As an example, on Wednesday December 31st 2014 at 36 minutes after 3pm and 36.123 seconds EST ${now()} would be evaluated to be a Date type representing that time. Since whole Expression Language expressions can only return Strings it would formatted as Wed Dec 31 15:36:03 EST 2014 when the expression completes.

Description: Coerces the Subject into a Number

Subject Type: String, Decimal, or Date

Arguments: No arguments

Return Type: Number

Examples: The Expression ${fileSize:toNumber()} converts the attribute value of "fileSize" to a number.

Description: Coerces the Subject into a Decimal

Subject Type: String, Whole Number or Date

Arguments: No arguments

Return Type: Decimal

Examples: The Expression ${fileSize:toDecimal()} converts the attribute value of "fileSize" to a decimal.

While the majority of functions in the Expression Language are called by using the syntax ${attributeName:function()}, there exist a few functions that are not expected to have subjects. In this case, the attribute name is not present. For example, the IP address of the machine can be obtained by using the Expression ${ip()}. All of the functions in this section are to be called without a subject. Attempting to call a subjectless function and provide it a subject will result in an error when validating the function.

Description: Returns the IP address of the machine.

Subject Type: No subject

Arguments: No arguments

Return Type: String

Examples: The IP address of the machine can be obtained by using the Expression ${ip()}.

Description: Returns the Hostname of the machine. An optional argument of type Boolean can be provided to specify whether or not the Fully Qualified Domain Name should be used. If false, or not specified, the hostname will not be fully qualified. If the argument is true but the fully qualified hostname cannot be resolved, the simple hostname will be returned.

Subject Type: No subject

Arguments:

Fully Qualified : Optional parameter that specifies whether or not the hostname should be fully qualified. If not specified, defaults to false.

Examples: The fully qualified hostname of the machine can be obtained by using the Expression ${hostname(true)}, while the simple hostname can be obtained by using either ${hostname(false)} or simply ${hostname()}.

Description: Returns a randomly generated type 4 UUID.

Subject Type: No Subject

Arguments: No arguments

Return Type: String

Examples: ${UUID()} returns a value similar to "de305d54-75b4-431b-adb2-eb6b9e546013"

Description: Returns a one-up value (starting at 0) and increasing over the lifetime of the running instance of NiFi. This value is not persisted across restarts and is not guaranteed to be unique across a cluster. This value is considered "one-up" in that if called multiple times across the NiFi instance, the values will be sequential. However, this counter is shared across all NiFi components, so calling this function multiple times from one Processor will not guarantee sequential values within the context of a particular Processor.

Subject Type: No Subject

Arguments: No arguments

Return Type: Number

Examples: If the previous value returned by nextInt was 5, the Expression ${nextInt():divide(2)} obtains the next available integer (6) and divides the result by 2, returning a value of 3.

Description: Returns its argument as a literal String value. This is useful in order to treat a string or a number at the beginning of an Expression as an actual value, rather than treating it as an attribute name. Additionally, it can be used when the argument is an embedded Expression that we would then like to evaluate additional functions against.

Subject Type: No Subject

Arguments:

${literal( ${allMatchingAttributes('a.*'):count()} ):gt(3)} returns true if there are more than 3 attributes whose names begin with the letter a.

Description: Access a processor’s state values by passing in the String key and getting the value back as a String. This is a special Expression Language function that only works with processors that explicitly allow EL to query state. Currently only UpdateAttribute does.

Subject Type: No Subject

Arguments:

Description: Returns the name of the thread used by the processor when evaluating the Expression. This can be useful when using a processor with multiple concurrent tasks and where some data uniqueness is required.

Subject Type: No Subject

Arguments: No arguments

Return Type: String

Examples: ${thread()} could return something like Timer-Driven Process Thread-4.

Description: Checks to see if any of the given attributes, match the given condition. This function has no subject and takes one or more arguments that are the names of attributes to which the remainder of the Expression is to be applied. If any of the attributes specified, when evaluated against the rest of the Expression, returns a value of true, then this function will return true. Otherwise, this function will return false.

Subject Type: No Subject

Arguments:

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "filename" contains "file.txt" consider the following examples:

Description: Checks to see if all of the given attributes match the given condition. This function has no subject and takes one or more arguments that are the names of attributes to which the remainder of the Expression is to be applied. If all of the attributes specified, when evaluated against the rest of the Expression, returns a value of true, then this function will return true. Otherwise, this function will return false.

Subject Type: No Subject

Arguments:

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "filename" contains "file.txt" consider the following examples:

Description: Checks to see if any of the given attributes, match the given condition. This function has no subject and takes one or more arguments that are Regular Expressions to match against attribute names. Any attribute whose name matches one of the supplied Regular Expressions will be evaluated against the rest of the Expression. If any of the attributes specified, when evaluated against the rest of the Expression, returns a value of true, then this function will return true. Otherwise, this function will return false.

Subject Type: No Subject

Arguments:

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "filename" contains "file.txt" consider the following examples:

Description: Checks to see if any of the given attributes, match the given condition. This function has no subject and takes one or more arguments that are Regular Expressions to match against attribute names. Any attribute whose name matches one of the supplied Regular Expressions will be evaluated against the rest of the Expression. If all of the attributes specified, when evaluated against the rest of the Expression, return a value of true, then this function will return true. Otherwise, this function will return false.

Subject Type: No Subject

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "filename" contains "file.txt" consider the following examples:

Description: Splits a String apart according to a delimiter that is provided, and then evaluates each of the values against the rest of the Expression. If the Expression, when evaluated against any of the individual values, returns true, this function returns true. Otherwise, the function returns false.

Subject Type: No Subject

Arguments:

Delineated Value : The value that is delineated. This is generally an embedded Expression, though it does not have to be.

Delimiter : The value to use to split apart the delineatedValue argument.

Examples: Given that the "number_list" attribute contains the value "1,2,3,4,5", and the "word_list" attribute contains the value "the,and,or,not", consider the following examples:

Description: Splits a String apart according to a delimiter that is provided, and then evaluates each of the values against the rest of the Expression. If the Expression, when evaluated against all of the individual values, returns true in each case, then this function returns true. Otherwise, the function returns false.

Subject Type: No Subject

Arguments:

Delineated Value : The value that is delineated. This is generally an embedded Expression, though it does not have to be.

Delimiter : The value to use to split apart the delineatedValue argument.

Examples: Given that the "number_list" attribute contains the value "1,2,3,4,5", and the "word_list" attribute contains the value "those,known,or,not", consider the following examples:

Description: Aggregate function that concatenates multiple values with the specified delimiter. This function may be used only in conjunction with the allAttributes, allMatchingAttributes, and allDelineatedValues functions.

Subject Type: String

Arguments:

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "filename" contains "file.txt" consider the following examples:

Description: Aggregate function that counts the number of non-null, non-false values returned by the allAttributes, allMatchingAttributes, and allDelineatedValues. This function may be used only in conjunction with the allAttributes, allMatchingAttributes, and allDelineatedValues functions.

Subject Type: Any

Arguments: No arguments

Return Type: Number

Examples: Given that the "abc" attribute contains the value "hello world", "xyz" contains "good bye world", and "number_list" contains "1,2,3,4,5" consider the following examples: