Groovy 2.2.1

groovy.json
[Groovy] Class JsonBuilder

java.lang.Object
  groovy.json.JsonBuilder
All Implemented Interfaces:
Writable

class JsonBuilder

A builder for creating JSON payloads.

This builder supports the usual builder syntax made of nested method calls and closures, but also some specific aspects of JSON data structures, such as list of values, etc. Please make sure to have a look at the various methods provided by this builder to be able to learn about the various possibilities of usage.

Example:


       def builder = new groovy.json.JsonBuilder()
       def root = builder.people {
           person {
               firstName 'Guillame'
               lastName 'Laforge'
               // Named arguments are valid values for objects too
               address(
                       city: 'Paris',
                       country: 'France',
                       zip: 12345,
               )
               married true
               // a list of values
               conferences 'JavaOne', 'Gr8conf'
           }
       }

       // creates a data structure made of maps (Json object) and lists (Json array)
       assert root instanceof Map

       assert builder.toString() == '{"people":{"person":{"firstName":"Guillame","lastName":"Laforge","address":{"city":"Paris","country":"France","zip":12345},"married":true,"conferences":["JavaOne","Gr8conf"]}}}'
 
Authors:
Guillaume Laforge
Since:
1.8.0


Property Summary
def content

Resulting data structure made of lists and maps, representing a JSON payload

 
Constructor Summary
JsonBuilder(def content = null)

Instanciates a JSON builder, possibly with some existing data structure.

 
Method Summary
def call(Map m)

Named arguments can be passed to the JSON builder instance to create a root JSON object

def call(List l)

A list of elements as arguments to the JSON builder creates a root JSON array

def call(Object... args)

Varargs elements as arguments to the JSON builder create a root JSON array

def call(Closure c)

A closure passed to a JSON builder will create a root JSON object

def invokeMethod(String name, Object args)

A method call on the JSON builder instance will create a root object with only one key whose name is the name of the method being called.

String toPrettyString()

Pretty-prints and formats the JSON payload.

String toString()

Serializes the internal data structure built with the builder to a conformant JSON payload string

Writer writeTo(Writer out)

The JSON builder implements the Writable interface, so that you can have the builder serialize itself the JSON payload to a writer.

 
Methods inherited from class Object
wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll
 

Property Detail

content

def content
Resulting data structure made of lists and maps, representing a JSON payload


 
Constructor Detail

JsonBuilder

JsonBuilder(def content = null)
Instanciates a JSON builder, possibly with some existing data structure.
Parameters:
content - a pre-existing data structure, default to null


 
Method Detail

call

def call(Map m)
Named arguments can be passed to the JSON builder instance to create a root JSON object

Example:


 def json = new JsonBuilder()
 json name: "Guillaume", age: 33

 assert json.toString() == '{"name":"Guillaume","age":33}'
 
Parameters:
m - a map of key / value pairs
Returns:
a map of key / value pairs


call

def call(List l)
A list of elements as arguments to the JSON builder creates a root JSON array

Example:


 def json = new JsonBuilder()
 def result = json([1, 2, 3])

 assert result instanceof List
 assert json.toString() == "[1,2,3]"
 
Parameters:
l - a list of values
Returns:
a list of values


call

def call(Object... args)
Varargs elements as arguments to the JSON builder create a root JSON array

Example:


 def json = new JsonBuilder()
 def result = json 1, 2, 3

 assert result instanceof List
 assert json.toString() == "[1,2,3]"
 
Parameters:
args - an array of values
Returns:
a list of values


call

def call(Closure c)
A closure passed to a JSON builder will create a root JSON object

Example:


 def json = new JsonBuilder()
 def result = json {
      name "Guillaume"
      age 33
 }

 assert result instanceof Map
 assert json.toString() == '{"name":"Guillaume","age":33}'
 
Parameters:
c - a closure whose method call statements represent key / values of a JSON object
Returns:
a map of key / value pairs


invokeMethod

def invokeMethod(String name, Object args)
A method call on the JSON builder instance will create a root object with only one key whose name is the name of the method being called. This method takes as arguments:

Example with a classicala builder-style:


 def json = new JsonBuilder()
 def result = json.person {
      name "Guillaume"
      age 33
 }

 assert result instanceof Map
 assert json.toString() == '{"person":{"name":"Guillaume","age":33}}'
 
Or alternatively with a method call taking named arguments:

 def json = new JsonBuilder()
 json.person name: "Guillaume", age: 33

 assert json.toString() == '{"person":{"name":"Guillaume","age":33}}'
 
If you use named arguments and a closure as last argument, the key/value pairs of the map (as named arguments) and the key/value pairs represented in the closure will be merged together — the closure properties overriding the map key/values in case the same key is used.

 def json = new JsonBuilder()
 json.person(name: "Guillaume", age: 33) { town "Paris" }

 assert json.toString() == '{"person":{"name":"Guillaume","age":33,"town":"Paris"}}'
 
The empty args call will create a key whose value will be an empty JSON object:

 def json = new JsonBuilder()
 json.person()

 assert json.toString() == '{"person":{}}'
 
Parameters:
name - the single key
args - the value associated with the key
Returns:
a map with a single key


toPrettyString

String toPrettyString()
Pretty-prints and formats the JSON payload.

This method calls the JsonLexer to parser the output of the builder, so this may not be an optimal method to call, and should be used mainly for debugging purpose for a human-readable output of the JSON content.

Returns:
a pretty printed JSON output


toString

String toString()
Serializes the internal data structure built with the builder to a conformant JSON payload string

Example:


 def json = new JsonBuilder()
 json { temperature 37 }
 
 assert json.toString() == '{"temperature":37}'
 
Returns:
a JSON output


writeTo

Writer writeTo(Writer out)
The JSON builder implements the Writable interface, so that you can have the builder serialize itself the JSON payload to a writer.

Example:


 def json = new JsonBuilder()
 json { temperature 37 }

 def out = new StringWriter()
 out << json

 assert out.toString() == '{"temperature":37}' 
 
Parameters:
out - a writer on which to serialize the JSON payload
Returns:
the writer


 

Copyright &copy; 2003-2013 The Codehaus. All rights reserved.