`last?` - documentation

[vemv]

Hi there,

thank you for the excellent library.

There doesn't appear to be documentation as for what last? means.

Cheers - V

[sg-qwt]

I accidentally discovered the meaning of last? by receiving a very large payload from some ws stream the other day.

If the payload is really large, the msg will be splitted in multi parts, with the first (n-1) parts of msg coming with last?=false, and the last msg with last?=true:

for example, I may receive 3 on-messages in a roll for a really huge json payload, and I need to concat them myself to get the complete json payload.

1. msg: "[{xxxxxxxxxxxxxxxxxxx," last?: false
2. msg: "xxxxxxxxxx", last?:false
3. msg: "xxxxxxx}]", last?:true

There seems some docs in jdk docs regarding that.
https://docs.oracle.com/en/java/javase/11/docs/api/java.net.http/java/net/http/WebSocket.html

Although I'm not sure the splitting behavior is controlled by server side or client side. Is there way to control the threshold size of whether to splitting msg into parts?

[shaunlebron]

The docs for Websocket.Listener shows this example for combining message chunks in onText:

WebSocket.Listener listener = new WebSocket.Listener() {

    List<CharSequence> parts = new ArrayList<>();
    CompletableFuture<?> accumulatedMessage = new CompletableFuture<>();

    public CompletionStage<?> onText(WebSocket webSocket,
                                     CharSequence message,
                                     boolean last) {
        parts.add(message);
        webSocket.request(1);
        if (last) {
            processWholeText(parts);
            parts = new ArrayList<>();
            accumulatedMessage.complete(null);
            CompletionStage<?> cf = accumulatedMessage;
            accumulatedMessage = new CompletableFuture<>();
            return cf;
        }
        return accumulatedMessage;
    }
...
}