4.0.0

[4.0.0] - 2022-12-19

This release revises the implementation of EventSource so that it does not create its own worker threads. The methods for starting and reading a stream now perform synchronous I/O, and the caller is responsible for choosing what thread to start the stream and read the stream on. This makes the core implementation simpler and more efficient, and reduces possibilities for deadlock. If you want to continue using the old asynchronous push model, see the com.launchdarkly.eventsource.background package.

The configuration API has also been revised to separate out the HTTP functionality and the backoff/retry logic into subcomponents which can be customized or replaced.

Added:

• EventSource methods readMessage(), readAnyEvents(), messages(), and anyEvents() for synchronously reading events.
• EventSource.Builder(ConnectStrategy) constructor and the ConnectStrategy and HttpConnectStrategy classes, for customizing connection parameters.
• EventSource.Builder(URI), (URL), and (HttpUrl) constructors, as shortcuts for minimal HTTP configuration.
• EventSource.Builder.errorStrategy and the ErrorStrategy class, for customizing error recovery behavior.
• EventSource.Builder.retryDelayStrategy and the RetryDelayStrategy and DefaultRetryDelayStrategy classes, for customizing or replacing backoff/jitter behavior.
• StreamEvent, CommentEvent, StartedEvent, and FaultEvent classes, representing types of information other than MessageEvent that you can read synchronously from the stream.
• The com.launchdarkly.eventsource.background package, containing the BackgroundEventSource wrapper for emulating the old push model.

Changed:

• EventSource.Builder.restart is renamed to interrupt, to clarify that the restarting of the stream is not done immediately but only happens if you continue trying to read events after interrupt().
• EventSource.Builder.backoffResetThreshold is renamed to retryDelayResetThreshold, to clarify that it applies to whatever kind of RetryDelayStrategy is being used even if that is not the default backoff strategy.
• EventSource.Builder.reconnectTime is renamed to retryDelay, to clarify that it is describing a duration rather than a moment in time.
• UnsuccessfulResponseException is renamed to StreamHttpErrorException, to clarify that it is specifically referring to an HTTP response with an error status.
• The implementation of streamEventData mode is now simpler and no longer uses PipedInputStream and PipedOutputStream internally.

Removed:

• ConnectionHandler and EventSource.Builder.connectionHandler(): replaced by ErrorStrategy.
• EventHandler and the EventSource.Builder(URI, EventHandler) constructor: replaced by BackgroundEventHandler if you are using BackgroundEventSource.
• EventSource.Builder methods connectTimeout, readTimeout, writeTimeout, method, body, headers, proxy, proxyAuthenticator, and requestTransformer: replaced by methods in HttpConnectStrategy.
• EventSource.Builder.maxReconnect: replaced by DefaultRetryDelayStrategy.maxDelay.
• EventSource.Builder.maxEventTasksInFlight: replaced by an equivalent option in BackgroundEventSource.