Apache FreeMarker Reference

Built-In String FreeMarker Operations

The following table shows you how to use some of the built-in string operations using a string variable called


     tester

, the value of which is sent to


     "hello world "

(with three trailing blank spaces). following expression allows the bot to output either the


     tester

value, or,


     no string found

if no value has been set for the variable.

${tester.value!'no string found'}


    contains


    ${tester.value?contains('world')?string ('You said world',
                  'You did not say world')}


    You said world

The contains('world') expressions returns either true or false . These boolean values are replaced with a string using the string ('string1','string2') function. ends_with ${tester.value?ends_with('world')?string ('Ends with world', 'Doesn't end with world')} Ends with world starts_with ${tester.value?starts_with('world')?string ('Starts with world', 'Doesn't start with world')} Doesn't start with world matches (regular expression returns true or false) ${tester.value?matches('^([^0-9]*)$')} The regular expression returns true or false depending on whether the value contains a number (in which case the boolean value is returned as false ). The tester value returns true . matches (regular expression returns a string) ${tester.value?matches('^([^0-9]*)$')?} Same as above, but this time, true is returned as a string. The matches('regular expression') function returns true or false as boolean types. To print true or false in a System.Output component, use ?string to perform a to-string conversion.

Note : You can’t use regular expression to return a group of values; use them to return a single matching value (or no match). Component

Imagine a case where different states get called depending on the user input (wine or beer), which is stored in the choice variable.

The casing of user input may be inconsistent, even within a word (WiNE). Instead of adding all possible variations to the component definition, use an FTL operation like


     upper_case

to make the casing uniform:

${choice.value?upper_case}

Example: Concatenating FTL Expressions

You can also concatenate FTL operations into a single expression.

In the following example, airline flight numbers (represented by the


       flight.value

variable) of


       UA1234

and


       UA
        1234

would both be transformed to

${flight.value?trim?lower_case?remove_beginning('ua ')?remove_beginning('ua')}"

Built-In FreeMarker Number Operations

The following table lists the built-in number operations and shows how they output the value set for the


       negativeValue

(-2.5) and


       positiveValue

(0.5175) variables:


       ${negativeValue.value?abs?string.percent}

The operator first changes the negative value to a positive. Then it converts it into percent, implicitly multiplying the value by 100.


       string

(with the decimal format value and various currencies)

Tip : Check out Charbase for other currency symbols. ${positiveValue.value?string['###.##']} ${positiveValue.value?string['###.##%']}

The operator adds adding a percentage character after multiplying the value by 100.


       ${positiveValue.value?string['##.###\u00A4']}

0.51 $


       ${positiveValue.value?string['##.###\u20AC']}

0.51 €


       ${positiveValue.value?string['##.###\u00A3']}

0.51 £


       round


       ${negativeValue.value?round}

The operator rounds to the nearest whole number. If the number ends with .5, then it rounds upwards.


       ${positiveValue.value?round}

The operator rounds to the nearest whole number. If the number ends with .5, then it rounds upwards.


       floor


       ${positiveValue.value?floor}

The operator rounds downwards.


       ceiling


       ${positiveValue.value?ceiling}

The operator rounds upwards.


       lower_abc


       ${negativeValue.value?abs?round?lower_abc}

The operator turns the negative value into a positive, then rounds it to 3. It returns c, the third letter of the alphabet. ${positiveValue.value?is_infinite?string} false

The operator returns false, because a float value is not infinite according to IEEE 754 (Standard for Floating-Point Arithmetic).

Note : The returned value would be a boolean without ?string .

Built-In FreeMarker Array Operations

Array (or sequence ) operations enable your bot to, among other things, determine the size of an array, sort arrays, or find content within an array.

You can use arrays to create mock data for testing, or for defining data structures that persist beyond user sessions. You can save an array in a custom component, in a flow or global variable. Here are arrays for


         person

and


         colors

variables, respectively.

[
    "firstName" : "Frank",
    "lastName" : "Normal"
    "firstName" : "Grant",
    "lastName" : "Right"
    "firstName" : "Geoff",
    "lastName" : "Power"
    "firstName" : "Marcelo",
    "lastName" : "Jump"
    "yellow", "blue", "red", "black", "white", "green"
  ]

These arrays are used to illustrate the array operations in the following table and in Example: Iterating Arrays .


         sort_by


         ${person.value?sort_by('lastName') [0].firstName}


         Marcelo

This operator sorts the


          person

array by the


          lastName

property in ascending order. It then prints the value of the corresponding


          firstName

property for final entry in the person array:

Jump, Marcelo

Normal, Frank

Power, Geoff

Right, Grant

Note : Unless you save the sorted array in a variable using System.SetVariable , the data remains sorted for a single request only. ${person.value?sort_by('lastName')?reverse[0].firstName} Grant —the values are sorted in descending order:

Right, Grant

Power, Geoff

Normal, Frank

Jump, Marcelo


          ${colors.value?join(',')}

Returns the


          colors

array as a comma-separated string:


          yellow, blue, red, black, white, green


          seq_contains


          ${colors.value?seq_contains('red')?string('Yes', 'No')

Returns

Yes

because the array contains red.

Note : ?seq_contains returns a boolean value. This value is then replaced by a string using the ?string('…','…') expression. ${colors.value?sort?join(',')} Returns the colors array as a comma-separated string in ascending order: black, blue, green, red, white, yellow reverse ${colors.value?sort?reverse?join(',')} Returns the colors array as a comma-separated string in descending order: yellow, blue, red, black, white, green

You can use array operations to return the results from the intent and entity processing. For example:

${skill.system.nlpresult.value.entityMatches[‘name of entity’]} returns an array of entities found in a user string that’s passed to the Intent Engine stored in the nlpresult variable.

${skill.system.nlpresult.value.intentMatches.summary[n].intent} returns the name of the intent that has a confidence ranking of n , where 0 represents the top-ranked intent, 1 represents the second ranked intent, etc.


            ${skill.system.nlpresult.value.intentMatches.summary[n].score}

returns the confidence score for the given intent.

For these two expressions,

is the index of the item you want to look up. For example, the expression to return the top-resolved intent name would be:

${skill.system.nlpresult.value.intentMatches.summary[0].intent}

For the top intent's score, the expression would be:

${skill.system.nlpresult.value.intentMatches.summary[0].score}

You can use these expressions for intents that scored above the confidence threshold, but you can also use them to return intents whose score falls below the confidence threshold. These expressions are not dependent on the confidence threshold value that's configured in the Skill's Settings page, so you can use them to return the candidate intents and their scores even when no intent could be resolved and an unresolvedIntent action has been triggered. In this case, you can, for example, use these expressions to return the top three intents and their sub-confidence threshold scores. If you need to refer to the intent that a user has selected after being asked to disambiguate, you can use ${system.intent.name} . ( ${skill.system.nlpresult.value.intentMatches.summary[0].intent} always returns the intent with the top score, which might not be the intent that the user selects when disambiguating.

Example: Iterating Arrays

Arrays determine the number of entities in the user input.

Description of the illustration arrayoutput.png

The following snippet from a Common Response component's Metadata property shows how to determine the size of the array held in the person variable and then iterate over its elements so that the skill outputs something like: responseItems: - type: "text" text: "${person?index+1}. ${person.firstName} ${person.lastName}" name: "Sorry" separateBubbles: true iteratorVariable: "person" The output described in this code is not sorted (that is, no sort_by operation is used).

Built-In FreeMarker Date Operations

The following expression derives the current date using the FreeMarker special variable reference,


                .now

and the built-in


                date

operator.

${.now?date}

The following table lists some of the built-in date operations that you can use to define properties and manipulate entity values.


               long

and


               number_to_date


               ${(.now?long + 86400000)?number_to_date }

Adds 24 hours to the current date. If the call is made on January 17, 2018, FreeMarker outputs January 18, 2018.


               string

(with formatting styles)


               ${.now?string.full}

Converts the current date to string formatted as Wednesday, January 17, 2018 6:35:12 PM UTC.


               ${.now?string.long}

Converts date to string with the following formatted output: January 17, 20186:36:47 PM UTC.


               ${.now?string.short}

Converts date to string with the following formatted output: 1/17/18 6:37 PM


               ${.now?string.medium}

Converts date to string with the following formatted output: Jan 17, 2018 6:38:35.


               ${.now?string.iso}

Prints the date in the ISO 8601 standard like 2018-01-17T18:54:01.129Z.


               string

(with specified output formats)


               ${.now?string['dd.MM.yyyy, HH:mm']}

Prints the current date in a custom format, like 17.01.2018, 18:58.


               ${.now?string['yyyy']}


               datetime

(with


               string

and formatting style)


               ${date_variable?datetime?string.short}

Converts the date to a string formatted as 1/17/18 6:37 PM.

The datetime operator enables FreeMarker to tell if the variable holds a date that contains both date and time information. Similarly, you can use the date or time operators to indicate if the date value contains only the date or only the time, but using datetime?string avoids errors. ${dateVar.value.date?long?number_to_date?date?string.short} Converts the date from the entity extraction to a string formatted as 11/17/18.

The date operator tells FreeMarker that the variable only holds a date, not time information. Using this format avoids errors.


               ${dateVar.value.date?long?number_to_date?string.medium}

Converts the date that’s derived from entity extraction to a string formatted as Jan 17, 2018.

Note : All other formats like full , short , long and iso work the same with dates that are derived from entity extraction. ${dateVar.value.date?long?number_to_date?string['dd.MM.yyyy']} Prints the date in custom format. For example: 17.01.2018, 18:58. ${dateVar.value.date?long?number_to_date?string['yyyy']} Prints the date derived from the entity in a custom format.

Example: Extracting Dates from User Input

The following examples are from a skill that manages appointments. When a user asks it, Can you arrange a meeting with Mr. Higgs a day later than tomorrow? , the bot uses a complex entity,


                  DATE

, to extract tomorrow from the request. It outputs the requested date using


                  ${(theDate.value.date?long +
        86400000)?number_to_date}

to add 24 hours (or 86,400,000 milliseconds) to "tomorrow".

Example: Setting a Default Date (When No Date Value Is Set)

If the user message doesn’t include any date information, your skill can prompt users for the date, or provide a default date. To provide the current date, you can use the following expression:

${.now?datetime?string.long}

FreeMarker-Accessible System Variables

Oracle Digital Assistant has a set of system variables through which you can retrieve useful information in your dialog flows through FreeMarker expressions.

In their simplest forms, these expressions take the following form:

${system.variableName}

Some variables can hold objects with nested properties that can be accessed using dot notation after the variable name in the following form.

${system.variableName.propertyName}

In addition, the nested property values can also be objects with nested properties.

Here are the system variables that are available through FreeMarker expressions.


                   system.authorizedUsers

A list of all of the users that have been authorized for a given group chat.


                   system.channelType

The type of channel of the current user session. Allowable values:


                   facebook


                   androidsdk


                   iossdk


                   websdk


                   slack


                   twilio


                   msteams


                   cortana


                   webhook

, and


                   test

If the session is running in the tester, the value corresponds to the channel type being simulated.


                   system.entityToResolve

Object representing the current composite bag item to resolve in the Common Response component when the variable property of the component is referring to a composite bag entity.The object has the following properties:


             nextRangeStart

- index number of the entity's allowable value list that will be navigated to when tapping the Show More button.


             updatedEntities

- list of composite bag items that were updated based on the last user message.


             needShowMoreButton

- Boolean property that can be used in as an


             expression

for the


             visible

property to conditionally render the Show More button to navigate to the next set of entity values.


             outOfOrderMatches

- list of bag items that were populated with a value based on the last user message when the user was prompted for another bag item.


             rangeStartVar

- name of the variable that holds the current range start of the entity values.


             validationErrors

- for the current bag item, list of error messages caused by an invalid value provided in the last user message.


             allMatches

- list of bag items that got a new or updated values based on the last user message.


             resolvingField

- name of current bag item the user is prompted for.


             userInput

- the last user message.


             skippedItems

- list of bag items where the maximum number of prompts for a value is exceeded.


             disambiguationValues

- list of allowed entity values that have matches in the last user message.


             enumValues

- list of entity allowed values for the current bag item.

See The system.entityToResolve Variable for examples of how to use system.entityToResolve . system.errorAction Error message text of an unexpected error thrown during execution of the state. system.errorState Name of the state that has thrown an unexpected error during execution. system.expectedState When user scrolls up the message history, and taps on an older "out-of-order" button this variable is populated with the name of the state that was expected to be executed, but never got executed because the user decided to tap on this "out-of-order" button. See also Configure the Dialog Flow for Unexpected Actions . system.intent.name Use to refer to the intent that a user has selected after being asked to disambiguate. (

${iResult.value.intentMatches.summary[0].intent}

always returns the intent with the top score, which might not be the intent that the user selects when disambiguating.)


            system.invalidUserInput

Boolean value set to


            true

when the user input cannot be matched to the requested variable type.


            system.message

Last message received by Oracle Digital Assistant. This variable has the following properties:


            channelConversation

- the channel conversation object, which has the following properties:


            botId


            channelType

- When running in the tester, this will return


            test

. If you want to get the name of the channel that is being simulated in the tester, use


            system.channelType

instead.


            channelName


            channelCategory

- Returns the type of channel. For DA as Agent channels, this returns


            botAsAgent


            groupConversation

- Returns


            true

if the conversation is a group chat.


            userId

- Returns the user ID. For DA as Agent channels, this will return the engagement ID.


            sessionId

- Returns the session ID. For DA as Agent channels, this will return the engagement ID.


            sessionExpiryDuration


            messagePayload

- the actual message sent by the user. The properties you can access depend on the type of message:

Text message: the


            text

property returning the actual message entered by the user

Postback message: the properties of the postback object, typically


            action

and


            variables

when using the Common Response component. For example, when the user taps a button that sets the variable


            pizzaSize

, this value can be retrieved using following expression:


            ${system.message.messagePayload.variables.pizzaSize}

Location message: the


            location

property, which holds a location object with following properties:


            title


            latitude


            longitude


           system.selectedCardIndex

This variable holds the index of the selected card when using the facility to optimize card rendering for text-only channels like Twilio. This optimization allows the user to select a card in a two step process: first a list of cards is presented, then the user can enter the number of the cards he wants to select. The corresponding index number of this card is stored in this variable.

The system variables in the above table are the only ones that you can use in FreeMarker expressions. Other system variables are not public and their use is subject to change, which means your skills can't rely on them.

For example, the system.routingFromSkill , system.routingToSkill , system.routingFromIntent , and system.routingToIntent variables are only available for specific digital assistant settings. See System Variables for Digital Assistants .