Support for JSON formatted messages

[ts5746]

Description

The Whiteflag Java Library should be able to export and import messages from and to a JSON format.

Rationale

To exchange Whiteflag messages and be interoperable with other software, the JSON language-independent open data interchange format should be natively supported by the WFJL. In addition, the Whiteflag standard provides a JSON schema of the Whiteflag message structure and syntax interoperable implementation of the standard.

Solution

Specification

• the WfMessage class must have a method, e.g. toJSON() that exports the message data to a stringified JSON object
• the WfMessage.Creator class must have a method, e.g. fromJSON(jsonString) that creates a new message from a stringified JSON object
• the JSON representation of the message must comply the Whiteflag JSON message schema

Affected components

t.b.d.

Alternatives

Alternatively, the conversion of message to and from a JSON representation should be performed by other software. It is, however, the purpose of the WFJL to support the development of Whiteflag-enabled applications by providing a standardised solution as much as possible.

[ts5746]

This feature has been implemented with the WfJsonMessage class in the org.whiteflag.protocol.util package, which is used by the WfMessage class. The solution is based on the jackson JSON library that has been added as a dependency. Usage:

import org.whiteflag.protocol.WfMessage;

WfMessage message = WfMessage.Creator.deserializeJson(jsonString);
String jsonMessage = message.toJson();

[ts5746]

JSON message schema check still needs to be added.

[ts5746]

The syntax checks against the Whiteflag JSON message schema will be added in version 1.2 and tracked separately.