javax.json

Interface JsonObject

All Superinterfaces:

JsonStructure, JsonValue, Map<String,JsonValue>

public interface JsonObject
extends JsonStructure, Map<String,JsonValue>

JsonObject class represents an immutable JSON object value (an unordered collection of zero or more name/value pairs). It also provides unmodifiable map view to the JSON object name/value mappings.

A JsonObject instance can be created from an input source using JsonReader.readObject(). For example:

 JsonReader jsonReader = Json.createReader(...);
 JsonObject object = jsonReader.readObject();
 jsonReader.close();
 

It can also be built from scratch using a JsonObjectBuilder.

For example 1: An empty JSON object can be built as follows:

 JsonObject object = Json.createObjectBuilder().build();
 

For example 2: The following JSON

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

can be built using :

 JsonObject value = Json.createObjectBuilder()
     .add("firstName", "John")
     .add("lastName", "Smith")
     .add("age", 25)
     .add("address", Json.createObjectBuilder()
         .add("streetAddress", "21 2nd Street")
         .add("city", "New York")
         .add("state", "NY")
         .add("postalCode", "10021"))
     .add("phoneNumber", Json.createArrayBuilder()
         .add(Json.createObjectBuilder()
             .add("type", "home")
             .add("number", "212 555-1234"))
         .add(Json.createObjectBuilder()
             .add("type", "fax")
             .add("number", "646 555-4567")))
     .build();
 

JsonObject can be written to JSON as follows:

 JsonWriter writer = ...
 JsonObject obj = ...;
 writer.writeObject(obj);
 

JsonObject values can be JsonObject, JsonArray, JsonString, JsonNumber, JsonValue.TRUE, JsonValue.FALSE, JsonValue.NULL. These values can be accessed using various accessor methods.

In the above example 2, "John" can be got using

 String firstName = object.getStringValue("firstName");
 

This map object provides read-only access to the JSON object data, and attempts to modify the map, whether direct or via its collection views, result in an UnsupportedOperationException.

The map object's iteration ordering is based on the order in which name/value pairs are added to the corresponding builder or the order in which name/value pairs appear in the corresponding stream.

Author:

Jitendra Kotamraju

Nested Class Summary

Nested classes/interfaces inherited from interface javax.json.JsonValue

JsonValue.ValueType

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

Fields inherited from interface javax.json.JsonValue

FALSE, NULL, TRUE

Method Summary

Methods

Modifier and Type	Method and Description
boolean	getBooleanValue(String name) Returns the boolean value of the associated mapping for the specified name.
boolean	getBooleanValue(String name, boolean defaultValue) Returns the boolean value of the associated mapping for the specified name.
int	getIntValue(String name) A convenience method for getValue(name, JsonNumber.class).getIntValue()
int	getIntValue(String name, int defaultValue) Returns the int value of the associated JsonNumber mapping for the specified name.
String	getStringValue(String name) A convenience method for getValue(name, JsonString.class).getStringValue()
String	getStringValue(String name, String defaultValue) Returns the string value of the associated JsonString mapping for the specified name.
<T extends JsonValue> T	getValue(String name, Class<T> clazz) Returns the value to which the specified name is mapped.

Methods inherited from interface javax.json.JsonValue

getValueType, toString

Methods inherited from interface java.util.Map

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values

Method Detail

getValue

<T extends JsonValue> T getValue(String name,
                               Class<T> clazz)

Returns the value to which the specified name is mapped. This is just a convenience method for (T) get(name) to get the value.

Parameters:

name - the name(key) whose associated value is to be returned

clazz - value class

Returns:

the value to which the specified name is mapped, or null if this object contains no mapping for the name(key)

Throws:

ClassCastException - if the value for specified name/key mapping is not assignable to the type T

getStringValue

String getStringValue(String name)

A convenience method for getValue(name, JsonString.class).getStringValue()

Parameters:

name - whose associated value is to be returned as String

Returns:

the String value to which the specified name is mapped

Throws:

NullPointerException - if the specified name doesn't have any mapping

ClassCastException - if the value for specified name mapping is not assignable to JsonString

getStringValue

String getStringValue(String name,
                    String defaultValue)

Returns the string value of the associated JsonString mapping for the specified name. If JsonString is found, then its JsonString.getStringValue() is returned. Otherwise, the specified default value is returned.

Parameters:

name - whose associated value is to be returned as String

defaultValue - a default value to be returned

Returns:

the string value of the associated mapping for the name, or the default value

getIntValue

int getIntValue(String name)

A convenience method for getValue(name, JsonNumber.class).getIntValue()

Parameters:

name - whose associated value is to be returned as int

Returns:

the int value to which the specified name is mapped

Throws:

NullPointerException - if the specified name doesn't have any mapping

ClassCastException - if the value for specified name mapping is not assignable to JsonNumber

getIntValue

int getIntValue(String name,
              int defaultValue)

Returns the int value of the associated JsonNumber mapping for the specified name. If JsonNumber is found, then its JsonNumber.getIntValue() is returned. Otherwise, the specified default value is returned.

Parameters:

name - whose associated value is to be returned as int

defaultValue - a default value to be returned

Returns:

the int value of the associated mapping for the name, or the default value

getBooleanValue

boolean getBooleanValue(String name)

Returns the boolean value of the associated mapping for the specified name. If the associated mapping is JsonValue.TRUE, then returns true. If the associated mapping is JsonValue.FALSE, then returns false.

Parameters:

name - whose associated value is to be returned as boolean

Returns:

the boolean value to which the specified name is mapped

Throws:

NullPointerException - if the specified name doesn't have any mapping

ClassCastException - if the value for specified name mapping is not assignable to JsonValue.TRUE or JsonValue.FALSE

getBooleanValue

boolean getBooleanValue(String name,
                      boolean defaultValue)

Returns the boolean value of the associated mapping for the specified name. If the associated mapping is JsonValue.TRUE, then returns true. If the associated mapping is JsonValue.FALSE, then returns false. Otherwise, the specified default value is returned.

Parameters:

name - whose associated value is to be returned as int

defaultValue - a default value to be returned

Returns:

the boolean value of the associated mapping for the name, or the default value