WebSocket (GWT 2.6.1)

All Superinterfaces:

EventTarget

All Known Implementing Classes:

JsWebSocket
```
public interface WebSocket
extends EventTarget
```
This is an experimental feature
Because this feature is still in development in some browsers, check the compatibility table for the proper prefixes to use in various browsers.

The WebSocket object provides the API for creating and managing a WebSocket connection to a server, as well as for sending and receiving data on the connection.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`CLOSED` The connection is closed or couldn't be opened.
`static int`	`CLOSING` The connection is in the process of closing.
`static int`	`CONNECTING` The connection is not yet open.
`static int`	`OPEN` The connection is open and ready to communicate.

Method Summary

Methods
Modifier and Type	Method and Description
`EventRemover`	`addEventListener(String type, EventListener listener)` Register an event handler of a specific event type on the `EventTarget`.
`EventRemover`	`addEventListener(String type, EventListener listener, boolean useCapture)` Register an event handler of a specific event type on the `EventTarget`.
`void`	`close()` Closes the WebSocket connection or connection attempt, if any.
`void`	`close(int code)` Closes the WebSocket connection or connection attempt, if any.
`void`	`close(int code, String reason)` Closes the WebSocket connection or connection attempt, if any.
`boolean`	`dispatchEvent(Event evt)` Dispatch an event to this `EventTarget`.
`String`	`getBinaryType()` A string indicating the type of binary data being transmitted by the connection.
`int`	`getBufferedAmount()` The number of bytes of data that have been queued using calls to but not yet transmitted to the network.
`String`	`getExtensions()` The extensions selected by the server.
`EventListener`	`getOnclose()` An event listener to be called when the WebSocket connection's `readyState` changes to `CLOSED`.
`EventListener`	`getOnerror()` An event listener to be called when an error occurs.
`EventListener`	`getOnmessage()` An event listener to be called when a message is received from the server.
`EventListener`	`getOnopen()` An event listener to be called when the WebSocket connection's `readyState` changes to `OPEN`; this indicates that the connection is ready to send and receive data.
`String`	`getProtocol()` A string indicating the name of the sub-protocol the server selected; this will be one of the strings specified in the `protocols` parameter when creating the WebSocket object.
`int`	`getReadyState()` The current state of the connection; this is one of the Ready state constants.
`String`	`getUrl()` The URL as resolved by the constructor.
`String`	`getURL()`
`void`	`removeEventListener(String type, EventListener listener)` Removes an event listener from the `EventTarget`.
`void`	`removeEventListener(String type, EventListener listener, boolean useCapture)` Removes an event listener from the `EventTarget`.
`boolean`	`send(String data)` Transmits data to the server over the WebSocket connection.
`void`	`setBinaryType(String arg)`
`void`	`setOnclose(EventListener arg)`
`void`	`setOnerror(EventListener arg)`
`void`	`setOnmessage(EventListener arg)`
`void`	`setOnopen(EventListener arg)`

- Field Detail
  - CLOSED
```
static final int CLOSED
```
    The connection is closed or couldn't be opened.
    
    See Also:
    Constant Field Values
  - CLOSING
```
static final int CLOSING
```
    The connection is in the process of closing.
    
    See Also:
    Constant Field Values
  - CONNECTING
```
static final int CONNECTING
```
    The connection is not yet open.
    
    See Also:
    Constant Field Values
  - OPEN
```
static final int OPEN
```
    The connection is open and ready to communicate.
    
    See Also:
    Constant Field Values
- Method Detail
  - getURL
```
String getURL()
```
  - getBinaryType
```
String getBinaryType()
```
    A string indicating the type of binary data being transmitted by the connection. This should be either "blob" if DOM Blob objects are being used or "arraybuffer" if ArrayBuffer objects are being used.
  - setBinaryType
```
void setBinaryType(String arg)
```
  - getBufferedAmount
```
int getBufferedAmount()
```
    The number of bytes of data that have been queued using calls to but not yet transmitted to the network. This value does not reset to zero when the connection is closed; if you keep calling , this will continue to climb. Read only.
  - getExtensions
```
String getExtensions()
```
    The extensions selected by the server. This is currently only the empty string or a list of extensions as negotiated by the connection.
  - getOnclose
```
EventListener getOnclose()
```
    An event listener to be called when the WebSocket connection's readyState changes to CLOSED. The listener receives a CloseEvent named "close".
  - setOnclose
```
void setOnclose(EventListener arg)
```
  - getOnerror
```
EventListener getOnerror()
```
    An event listener to be called when an error occurs. This is a simple event named "error".
  - setOnerror
```
void setOnerror(EventListener arg)
```
  - getOnmessage
```
EventListener getOnmessage()
```
    An event listener to be called when a message is received from the server. The listener receives a MessageEvent named "message".
  - setOnmessage
```
void setOnmessage(EventListener arg)
```
  - getOnopen
```
EventListener getOnopen()
```
    An event listener to be called when the WebSocket connection's readyState changes to OPEN; this indicates that the connection is ready to send and receive data. The event is a simple one with the name "open".
  - setOnopen
```
void setOnopen(EventListener arg)
```
  - getProtocol
```
String getProtocol()
```
    A string indicating the name of the sub-protocol the server selected; this will be one of the strings specified in the protocols parameter when creating the WebSocket object.
  - getReadyState
```
int getReadyState()
```
    The current state of the connection; this is one of the Ready state constants. Read only.
  - getUrl
```
String getUrl()
```
    The URL as resolved by the constructor. This is always an absolute URL. Read only.
  - addEventListener
```
EventRemover addEventListener(String type,
                            EventListener listener)
```
    Description copied from interface: EventTarget
    
    Register an event handler of a specific event type on the EventTarget.
    
    Specified by:
    
    addEventListener in interface EventTarget
  - addEventListener
```
EventRemover addEventListener(String type,
                            EventListener listener,
                            boolean useCapture)
```
    Description copied from interface: EventTarget
    
    Register an event handler of a specific event type on the EventTarget.
    
    Specified by:
    
    addEventListener in interface EventTarget
  - close
```
void close()
```
    Closes the WebSocket connection or connection attempt, if any. If the connection is already CLOSED, this method does nothing.
    
    Parameters
    
    code Optional
    
    A numeric value indicating the status code explaining why the connection is being closed. If this parameter is not specified, a default value of 1000 (indicating a normal "transaction complete" closure) is assumed. See the list of status codes on the CloseEvent page for permitted values.
    
    reason Optional
    
    A human-readable string explaining why the connection is closing. This string must be no longer than 123 UTF-8 characters.
    
    Exceptions thrown
    
    INVALID_ACCESS_ERR
    
    An invalid code was specified.
    
    SYNTAX_ERR
    
    The reason string is too long or contains unpaired surrogates.
  - close
```
void close(int code)
```
    Closes the WebSocket connection or connection attempt, if any. If the connection is already CLOSED, this method does nothing.
    
    Parameters
    
    code Optional
    
    A numeric value indicating the status code explaining why the connection is being closed. If this parameter is not specified, a default value of 1000 (indicating a normal "transaction complete" closure) is assumed. See the list of status codes on the CloseEvent page for permitted values.
    
    reason Optional
    
    A human-readable string explaining why the connection is closing. This string must be no longer than 123 UTF-8 characters.
    
    Exceptions thrown
    
    INVALID_ACCESS_ERR
    
    An invalid code was specified.
    
    SYNTAX_ERR
    
    The reason string is too long or contains unpaired surrogates.
  - close
```
void close(int code,
         String reason)
```
    Closes the WebSocket connection or connection attempt, if any. If the connection is already CLOSED, this method does nothing.
    
    Parameters
    
    code Optional
    
    A numeric value indicating the status code explaining why the connection is being closed. If this parameter is not specified, a default value of 1000 (indicating a normal "transaction complete" closure) is assumed. See the list of status codes on the CloseEvent page for permitted values.
    
    reason Optional
    
    A human-readable string explaining why the connection is closing. This string must be no longer than 123 UTF-8 characters.
    
    Exceptions thrown
    
    INVALID_ACCESS_ERR
    
    An invalid code was specified.
    
    SYNTAX_ERR
    
    The reason string is too long or contains unpaired surrogates.
  - dispatchEvent
```
boolean dispatchEvent(Event evt)
```
    Description copied from interface: EventTarget
    
    Dispatch an event to this EventTarget.
    
    Specified by:
    
    dispatchEvent in interface EventTarget
  - removeEventListener
```
void removeEventListener(String type,
                       EventListener listener)
```
    Description copied from interface: EventTarget
    
    Removes an event listener from the EventTarget.
    
    Specified by:
    
    removeEventListener in interface EventTarget
  - removeEventListener
```
void removeEventListener(String type,
                       EventListener listener,
                       boolean useCapture)
```
    Description copied from interface: EventTarget
    
    Removes an event listener from the EventTarget.
    
    Specified by:
    
    removeEventListener in interface EventTarget
  - send
```
boolean send(String data)
```
    Transmits data to the server over the WebSocket connection.
    
    Parameters
    
    data
    
    A text string to send to the server.
    
    Exceptions thrown
    
    INVALID_STATE_ERR
    
    The connection is not currently OPEN.
    
    SYNTAX_ERR
    
    The data is a string that has unpaired surrogates.
    
    Remarks
    
    Gecko 6.0 note
    (Firefox 6.0 / Thunderbird 6.0 / SeaMonkey 2.3)
    
    Gecko's implementation of the send() method differs somewhat from the specification in Gecko 6.0; Gecko returns a boolean indicating whether or not the connection is still open (and, by extension, that the data was successfully queued or transmitted); this is corrected in Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5) . In addition, at this time, Gecko does not support ArrayBuffer or Blob data types.

Interface WebSocket

Field Summary

Method Summary

Field Detail

CLOSED

CLOSING

CONNECTING

OPEN

Method Detail

getURL

getBinaryType

setBinaryType

getBufferedAmount

getExtensions

getOnclose

setOnclose

getOnerror

setOnerror

getOnmessage

setOnmessage

getOnopen

setOnopen

getProtocol

getReadyState

getUrl

addEventListener

addEventListener

close

Parameters

Exceptions thrown

close

Parameters

Exceptions thrown

close

Parameters

Exceptions thrown

dispatchEvent

removeEventListener

removeEventListener

send

Parameters

Exceptions thrown

Remarks