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package javax.websocket;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.nio.ByteBuffer;
import java.util.concurrent.Future;
/**
* The RemoteEndpoint object is supplied by the container and represents the
* 'other end' or peer of the Web Socket conversation. Instances of the RemoteEndpoint
* are obtained from the Session using {@link Session#getBasicRemote()} or
* {@link Session#getAsyncRemote()}.
* Objects of this kind include numerous ways to send web socket messages. There
* are two kinds of RemoteEndpoint objects: RemoteEndpoint.Basic for synchronous
* sending of websocket messages, and RemoteEndpoint.Async for sending messages
* asynchronously.
*
* There is no guarantee of the successful delivery of a web socket message to
* the peer, but if the action of sending a message causes an error known to
* the container, the API throws it.
* RemoteEndpoints include a variety of ways to send messages: by whole message,
* in parts, and in various data formats including websocket pings and pongs.
*
*
Implementations
* may or may not support batching of messages. More detail of the expected semantics
* of implementations that do support batching are laid out in {@link RemoteEndpoint#setBatchingAllowed(boolean)}.
*
*
Note: Implementations may choose their own schemes for sending large messages in smaller parts. These
* schemes may or may not bear a relationship to the underlying websocket dataframes in which the message
* is ultimately sent on the wire.
*
*
If the underlying connection is closed and methods on the RemoteEndpoint are attempted to be called, they will
* result in an error being generated. For the methods that send messages, this will be an IOException, for the methods
* that alter configuration of the endpoint, this will be runtime IllegalArgumentExceptions.
* @author dannycoward
*/
public interface RemoteEndpoint {
/**
* Indicate to the implementation that it is allowed to batch outgoing messages
* before sending. Not all implementations support batching of outgoing messages.
* The default mode for RemoteEndpoints is false. If the developer
* has indicated that batching of outgoing
* messages is permitted, then the developer must call flushBatch() in order to be
* sure that all the messages passed into the send methods of this RemoteEndpoint
* are sent.
* When batching is allowed, the implementations send operations are considered
* to have completed if the message has been written to the local batch, in
* the case when there is still room in the batch for the message, and are considered
* to have completed if the batch has been send to the peer and the remainder
* written to the new batch, in the case when
* writing the message causes the batch to need to be sent. The blocking
* and asynchronous send methods use this notion of completion in order
* to complete blocking calls, notify SendHandlers and complete Futures respectively.
* When batching is allowed, if the developer has called send methods
* on this RemoteEndpoint without calling flushBatch(), then the implementation
* may not have sent all the messages the developer has asked to be sent. If
* the parameter value is false and the implementation has a batch of unsent messages,
* then the implementation must immediately send the batch of unsent messages.
*
* @param allowed whether the implementation is allowed to batch messages.
* @throws IOException if batching is being disabled and there are unsent messages
* this error may be thrown as the implementation sends the batch of unsent messages if
* there is a problem.
*/
void setBatchingAllowed(boolean allowed) throws IOException;
/**
* Return whether the implementation is allowed to batch outgoing messages
* before sending. The default mode for RemoteEndpoints is false. The value
* may be changed by calling {@link #setBatchingAllowed(boolean) setBatchingAllowed}.
*/
boolean getBatchingAllowed();
/**
* This method is only used when batching is allowed for this RemoteEndpint. Calling
* this method forces the implementation to send any unsent messages it has been batching.
*/
void flushBatch() throws IOException;
/**
* Send a Ping message containing the given application data to the remote endpoint. The corresponding Pong message may be picked
* up using the MessageHandler.Pong handler.
*
* @param applicationData the data to be carried in the ping request.
* @throws IOException if the ping failed to be sent
* @throws IllegalArgumentException if the applicationData exceeds the maximum allowed payload of 125 bytes
*/
void sendPing(ByteBuffer applicationData) throws IOException, IllegalArgumentException;
/**
* Allows the developer to send an unsolicited Pong message containing the given application
* data in order to serve as a unidirectional
* heartbeat for the session.
*
* @param applicationData the application data to be carried in the pong response.
* @throws IOException if the pong failed to be sent
* @throws IllegalArgumentException if the applicationData exceeds the maximum allowed payload of 125 bytes
*/
void sendPong(ByteBuffer applicationData) throws IOException, IllegalArgumentException;
/**
* This representation of the peer of a web socket conversation has the ability
* to send messages asynchronously. The point of completion of the send is
* defined when all the supplied data has been written to the underlying connection.
* The completion handlers for the asynchronous methods are always called with
* a different thread from that which initiated the send.
*/
interface Async extends RemoteEndpoint {
/**
* Return the number of milliseconds the implementation will timeout
* attempting to send a websocket message. A non-positive number indicates
* the implementation will not timeout attempting to send a websocket message
* asynchronously. This value overrides the default value assigned in the
* WebSocketContainer.
*
* @return the timeout time in milliseconds.
*/
long getSendTimeout();
/**
* Sets the number of milliseconds the implementation will timeout
* attempting to send a websocket message. A non-positive number indicates
* the implementation will not timeout attempting to send a websocket message
* asynchronously. This value overrides the default value assigned in the
* WebSocketContainer.
*
* @param timeoutmillis The number of milliseconds this RemoteEndpoint will wait before timing out
* an incomplete asynchronous message send.
*/
void setSendTimeout(long timeoutmillis);
/**
* Initiates the asynchronous transmission of a text message. This method returns before the message
* is transmitted. Developers provide a callback to be notified when the message has been
* transmitted. Errors
* in transmission are given to the developer in the SendResult object.
*
* @param text the text being sent.
* @param handler the handler which will be notified of progress.
* @throws IllegalArgumentException if the text or the handler is {@code null}.
*/
void sendText(String text, SendHandler handler);
/**
* Initiates the asynchronous transmission of a text message. This method
* returns before the message is transmitted. Developers use the
* returned Future object to track progress of the transmission. The
* Future's get() method returns {@code null} upon successful completion. Errors
* in transmission are wrapped in the {@link java.util.concurrent.ExecutionException}
* thrown when querying the Future object.
*
* @param text the text being sent.
* @return the Future object representing the send operation.
* @throws IllegalArgumentException if the text is {@code null}.
*/
Future sendText(String text);
/**
* Initiates the asynchronous transmission of a binary message. This method returns before the message
* is transmitted. Developers use the returned Future object to track progress of the transmission. The
* Future's get() method returns {@code null} upon successful completion. Errors
* in transmission are wrapped in the {@link java.util.concurrent.ExecutionException}
* thrown when querying the Future object.
*
* @param data the data being sent.
* @return the Future object representing the send operation.
* @throws IllegalArgumentException if the data is {@code null}.
*/
Future sendBinary(ByteBuffer data);
/**
* Initiates the asynchronous transmission of a binary message. This method returns before the message
* is transmitted. Developers provide a callback to be notified when the message has been
* transmitted. Errors in transmission are given to the developer in the SendResult object.
*
* @param data the data being sent, must not be {@code null}.
* @param handler the handler that will be notified of progress, must not be {@code null}.
* @throws IllegalArgumentException if either the data or the handler are {@code null}.
*/
void sendBinary(ByteBuffer data, SendHandler handler);
/**
* Initiates the asynchronous transmission of a custom developer object.
* The developer will have provided an encoder for this object
* type in the endpoint configuration. Containers will by default be able
* to encode java primitive types and their object equivalents, otherwise
* the developer must have provided an encoder for the object type in the
* endpoint configuration. Progress may be tracked using the Future object.
* The Future's get() methods return {@code null} upon successful completion. Errors
* in transmission are wrapped in the {@link java.util.concurrent.ExecutionException}
* thrown when querying the Future object.
*
* @param data the object being sent.
* @return the Future object representing the send operation.
* @throws IllegalArgumentException if the data is {@code null}.
*/
Future sendObject(Object data);
/**
* Initiates the asynchronous transmission of a custom developer object.
* Containers will by default be able to encode java primitive types and
* their object equivalents, otherwise the developer must have provided an encoder
* for the object type in the endpoint configuration. Developers
* are notified when transmission is complete through the supplied callback object.
*
* @param data the object being sent.
* @param handler the handler that will be notified of progress, must not be {@code null}.
* @throws IllegalArgumentException if either the data or the handler are {@code null}.
*/
void sendObject(Object data, SendHandler handler);
}
/**
* This representation of the peer of a web socket conversation has the ability
* to send messages synchronously. The point of completion of the send is
* defined when all the supplied data has been written to the underlying connection.
* The methods for sending messages on the RemoteEndpoint.Basic block until this
* point of completion is reached, except for {@link RemoteEndpoint.Basic#getSendStream() getSendStream}
* and {@link RemoteEndpoint.Basic#getSendWriter() getSendWriter} which present
* traditional blocking I/O streams to write messages.
*
* If the websocket connection underlying this RemoteEndpoint is busy sending a message when a call is made
* to send another one, for example if two threads attempt to call a send method
* concurrently, or if a developer attempts to send a new message while in the
* middle of sending an existing one, the send method called while
* the connection is already busy may throw an {@link java.lang.IllegalStateException}.
*/
interface Basic extends RemoteEndpoint {
/**
* Send a text message, blocking until all of the message has been transmitted.
*
* @param text the message to be sent.
* @throws IOException if there is a problem delivering the message.
* @throws IllegalArgumentException if the text is {@code null}.
*/
void sendText(String text) throws IOException;
/**
* Send a binary message, returning when all of the message has been transmitted.
*
* @param data the message to be sent.
* @throws IOException if there is a problem delivering the message.
* @throws IllegalArgumentException if the data is {@code null}.
*/
void sendBinary(ByteBuffer data) throws IOException;
/**
* Send a text message in parts, blocking until all of the message has been transmitted. The runtime
* reads the message in order. Non-final parts of the message are sent with isLast set to false. The final part
* must be sent with isLast set to true.
*
* @param partialMessage the parts of the message being sent.
* @param isLast Whether the partial message being sent is the last part of the message.
* @throws IOException if there is a problem delivering the message fragment.
* @throws IllegalArgumentException if the partialMessage is {@code null}.
*/
void sendText(String partialMessage, boolean isLast) throws IOException;
/**
* Send a binary message in parts, blocking until all of the message has been transmitted. The runtime
* reads the message in order. Non-final parts are sent with isLast set to false. The final piece
* must be sent with isLast set to true.
*
* @param partialByte the part of the message being sent.
* @param isLast Whether the partial message being sent is the last part of the message.
* @throws IOException if there is a problem delivering the partial message.
* @throws IllegalArgumentException if the partialByte is {@code null}.
*/
void sendBinary(ByteBuffer partialByte, boolean isLast) throws IOException; // or Iterable
/**
* Opens an output stream on which a binary message may be sent. The developer must close the output stream in order
* to indicate that the complete message has been placed into the output stream.
*
* @return the output stream to which the message will be written.
* @throws IOException if there is a problem obtaining the OutputStream to write the binary message.
*/
OutputStream getSendStream() throws IOException;
/**
* Opens an character stream on which a text message may be sent. The developer must close the writer in order
* to indicate that the complete message has been placed into the character stream.
*
* @return the writer to which the message will be written.
* @throws IOException if there is a problem obtaining the Writer to write the text message.
*/
Writer getSendWriter() throws IOException;
/**
* Sends a custom developer object, blocking until it has been transmitted.
* Containers will by default be able to encode java primitive types and
* their object equivalents, otherwise the developer must have provided an encoder
* for the object type in the endpoint configuration. A developer-provided
* encoder for a Java primitive type overrides the container default
* encoder.
*
* @param data the object to be sent.
* @throws IOException if there is a communication error sending the message object.
* @throws EncodeException if there was a problem encoding the message object into the form of a native websocket message.
* @throws IllegalArgumentException if the data parameter is {@code null}
*/
void sendObject(Object data) throws IOException, EncodeException;
}
}