Package com.api.jsonata4java

Class Expression

java.lang.Object

com.api.jsonata4java.Expression

All Implemented Interfaces:

Serializable

public class Expression
extends Object
implements Serializable

Class to provide embedding and extending JSONata features

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
Expression(String expression)	Constructor for Expression

Method Summary

Modifier and Type	Method	Description
void	assign(Binding binding)	Assign the binding to the environment preparing for evaluation
void	assign(String varname, String expression)	Assign the expression (variable or function declaration) to the variable name supplied
void	clear()	Remove all bindings
static List<Binding>	createBindings(com.fasterxml.jackson.databind.JsonNode bindingObj)	Establish a list of bindings for the given json object
com.fasterxml.jackson.databind.JsonNode	evaluate(com.fasterxml.jackson.databind.JsonNode rootContext)	Generate a result form the Expression's parsed expression and variable assignments or registered functions
com.fasterxml.jackson.databind.JsonNode	evaluate(com.fasterxml.jackson.databind.JsonNode rootContext, com.fasterxml.jackson.databind.JsonNode bindingObj)	Generate a result form the Expression's parsed expression and variable assignments or registered functions specified in the bindings object
com.fasterxml.jackson.databind.JsonNode	evaluate(com.fasterxml.jackson.databind.JsonNode rootContext, List<Binding> bindings)	Generate a result form the Expression's parsed expression and variable assignments or registered functions specified in the list of bindings
static Expression	jsonata(String expression)	Genearte a new Expression based on evaluating the supplied expression
static void	main(String[] args)	Testing the various methods based on https://docs.jsonata.org/embedding-extending#expressionregisterfunctionname-implementation-signature
void	registerFunction(String fctName, String implementation)	Registers a function implementation (declaration) by name

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Expression

public Expression(String expression)
           throws ParseException,
                  IOException

Constructor for Expression

Parameters:

expression - the logic to be parsed for later execution via evaluate methods

Throws:

ParseException

IOException

Method Detail

jsonata

public static Expression jsonata(String expression)
                          throws ParseException,
                                 IOException

Genearte a new Expression based on evaluating the supplied expression

Parameters:

expression - the logic to be parsed for later execution via the evaluate methods

Returns:

new Expression object

Throws:

ParseException

IOException

createBindings

public static List<Binding> createBindings(com.fasterxml.jackson.databind.JsonNode bindingObj)

Establish a list of bindings for the given json object

Parameters:

bindingObj - the json to calculate the bindings for

Returns:

the list of bindings for the provided json

main

public static void main(String[] args)

Testing the various methods based on https://docs.jsonata.org/embedding-extending#expressionregisterfunctionname-implementation-signature

Parameters:

args - not used

assign

public void assign(Binding binding)

Assign the binding to the environment preparing for evaluation

Parameters:

binding -

clear

public void clear()

Remove all bindings

assign

public void assign(String varname,
                   String expression)
            throws ParseException,
                   IOException

Assign the expression (variable or function declaration) to the variable name supplied

Parameters:

varname - name of the variable to map to a variable expression or function declaration expression

expression - logic to be assigned to the variable name

Throws:

ParseException

IOException

evaluate

public com.fasterxml.jackson.databind.JsonNode evaluate(com.fasterxml.jackson.databind.JsonNode rootContext)
                                                 throws ParseException

Generate a result form the Expression's parsed expression and variable assignments or registered functions

Parameters:

rootContext - JSON object specifying the content used to evaluate the expression

Returns:

the result from executing the Expression's parsed expression and variable assignments or registered functions. A null will be returned if no match is found (note a JSON null will result in a JsonNode of type NullNode).

Throws:

ParseException

evaluate

public com.fasterxml.jackson.databind.JsonNode evaluate(com.fasterxml.jackson.databind.JsonNode rootContext,
                                                        List<Binding> bindings)
                                                 throws ParseException

Generate a result form the Expression's parsed expression and variable assignments or registered functions specified in the list of bindings

Parameters:

rootContext - JSON object specifying the content used to evaluate the expression

bindings - assignments of variable names to variable expressions or function declarations

Returns:

the result from executing the Expression's parsed expression and variable assignments or registered functions specified in the list of bindings. A null will be returned if no match is found (note a JSON null will result in a JsonNode of type NullNode).

Throws:

ParseException

evaluate

public com.fasterxml.jackson.databind.JsonNode evaluate(com.fasterxml.jackson.databind.JsonNode rootContext,
                                                        com.fasterxml.jackson.databind.JsonNode bindingObj)
                                                 throws ParseException,
                                                        IOException

Generate a result form the Expression's parsed expression and variable assignments or registered functions specified in the bindings object

Parameters:

rootContext - JSON object specifying the content used to evaluate the expression

bindingObj - a JSON object containing the assignments of variable names to variable expressions or function declarations

Returns:

the result from executing the Expression's parsed expression and variable assignments or registered functions specified in the bindings object

Throws:

ParseException

IOException

registerFunction

public void registerFunction(String fctName,
                             String implementation)
                      throws ParseException,
                             IOException

Registers a function implementation (declaration) by name

Parameters:

fctName - the name of the function

implementation - the function declaration

Throws:

ParseException

IOException