Package jakarta.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.getString("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.

  • Method Details

    • getJsonArray

      JsonArray getJsonArray(String name)
      Returns the array value to which the specified name is mapped. This is a convenience method for (JsonArray)get(name) to get the value.
      Parameters:
      name - the name whose associated value is to be returned
      Returns:
      the array value to which the specified name is mapped, or null if this object contains no mapping for the name
      Throws:
      ClassCastException - if the value to which the specified name is mapped is not assignable to JsonArray type

    • getJsonObject

      JsonObject getJsonObject(String name)
      Returns the object value to which the specified name is mapped. This is a convenience method for (JsonObject)get(name) to get the value.
      Parameters:
      name - the name whose associated value is to be returned
      Returns:
      the object value to which the specified name is mapped, or null if this object contains no mapping for the name
      Throws:
      ClassCastException - if the value to which the specified name is mapped is not assignable to JsonObject type

    • getJsonNumber

      JsonNumber getJsonNumber(String name)
      Returns the number value to which the specified name is mapped. This is a convenience method for (JsonNumber)get(name) to get the value.
      Parameters:
      name - the name whose associated value is to be returned
      Returns:
      the number value to which the specified name is mapped, or null if this object contains no mapping for the name
      Throws:
      ClassCastException - if the value to which the specified name is mapped is not assignable to JsonNumber type

    • getJsonString

      JsonString getJsonString(String name)
      Returns the string value to which the specified name is mapped. This is a convenience method for (JsonString)get(name) to get the value.
      Parameters:
      name - the name whose associated value is to be returned
      Returns:
      the string value to which the specified name is mapped, or null if this object contains no mapping for the name
      Throws:
      ClassCastException - if the value to which the specified name is mapped is not assignable to JsonString type

    • getString

      String getString(String name)
      A convenience method for getJsonString(name).getString()
      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

    • getString

      String getString(String name, String defaultValue)
      Returns the string value of the associated JsonString mapping for the specified name. If JsonString is found, then its JsonString.getString() 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

    • getInt

      int getInt(String name)
      A convenience method for getJsonNumber(name).intValue()
      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

    • getInt

      int getInt(String name, int defaultValue)
      Returns the int value of the associated JsonNumber mapping for the specified name. If JsonNumber is found, then its JsonNumber.intValue() 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

    • getBoolean

      boolean getBoolean(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

    • getBoolean

      boolean getBoolean(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

    • isNull

      boolean isNull(String name)
      Returns true if the associated value for the specified name is JsonValue.NULL.
      Parameters:
      name - name whose associated value is checked
      Returns:
      return true if the associated value is JsonValue.NULL, otherwise false
      Throws:
      NullPointerException - if the specified name doesn't have any mapping