Module java.net.http
Package java.net.http

# Interface WebSocket.Builder

Enclosing interface:
  WebSocket

public static interface WebSocket.Builder
A builder of WebSocket Clients.

Builders are created by invoking `HttpClient.newWebSocketBuilder`. The intermediate (setter-like) methods change the state of the builder and return the same builder they have been invoked on. If an intermediate method is not invoked, an appropriate default value (or behavior) will be assumed. A `Builder` is not safe for use by multiple threads without external synchronization.

Since:
  11

## Method Summary

Modifier and Type
Method
Description
`CompletableFuture<WebSocket>`
`buildAsync(URI uri, WebSocket.Listener listener)`
Builds a `WebSocket` connected to the given `URI` and associated with the given `Listener`.
`WebSocket.Builder`
`connectTimeout(Duration timeout)`
Sets a timeout for establishing a WebSocket connection.
`WebSocket.Builder`
`header(String name, String value)`
Adds the given name-value pair to the list of additional HTTP headers sent during the opening handshake.
`WebSocket.Builder`
`subprotocols(String mostPreferred, String... lesserPreferred)`
Sets a request for the given subprotocols.

## Method Details

### header

WebSocket.Builder header(String name, String value)
Adds the given name-value pair to the list of additional HTTP headers sent during the opening handshake.

Headers defined in the WebSocket Protocol are illegal. If this method is not invoked, no additional HTTP headers will be sent.

Parameters:
  `name` - the header name
  `value` - the header value
Returns:
  this builder

### connectTimeout

WebSocket.Builder connectTimeout(Duration timeout)
Sets a timeout for establishing a WebSocket connection.

If the connection is not established within the specified duration then building of the `WebSocket` will fail with `HttpTimeoutException`. If this method is not invoked then the infinite timeout is assumed.

Parameters:
  `timeout` - the timeout, non-negative, non-ZERO
Returns:
  this builder

### subprotocols

WebSocket.Builder subprotocols(String mostPreferred, String... lesserPreferred)
Sets a request for the given subprotocols.

After the `WebSocket` has been built, the actual subprotocol can be queried through `WebSocket.getSubprotocol()`.

Subprotocols are specified in the order of preference. The most preferred subprotocol is specified first. If there are any additional subprotocols they are enumerated from the most preferred to the least preferred.

Subprotocols not conforming to the syntax of subprotocol identifiers are illegal. If this method is not invoked then no subprotocols will be requested.

Parameters:
  `mostPreferred` - the most preferred subprotocol
  `lesserPreferred` - the lesser preferred subprotocols
Returns:
  this builder

### buildAsync

CompletableFuture<WebSocket> buildAsync(URI uri, WebSocket.Listener listener)
Builds a `WebSocket` connected to the given `URI` and associated with the given `Listener`.

Returns a `CompletableFuture` which will either complete normally with the resulting `WebSocket` or complete exceptionally with one of the following errors:

- `IOException` - if an I/O error occurs
- `WebSocketHandshakeException` - if the opening handshake fails
- `HttpTimeoutException` - if the opening handshake does not complete within the timeout
- `InterruptedException` - if the operation is interrupted
- `SecurityException` - if a security manager has been installed and it denies `access` to `uri`. Security checks contains more information relating to the security context in which the listener is invoked.
- `IllegalArgumentException` - if any of the arguments of this builder's methods are illegal

Parameters:
  `uri` - the WebSocket URI
  `listener` - the listener
Returns:
  a `CompletableFuture` with the `WebSocket`