Struct erdos::dataflow::stream::ReadStream

pub struct ReadStream<D: Data> { /* private fields */ }

A ReadStream allows operators to pull Messages from a stream.

Example

The following example shows an operator that prints out messages received from a ReadStream.

struct PrintMessageOperator<D: Data> {
    phantom: PhantomData<D>,
}

impl<D: Data> Sink<(), D> for PrintMessageOperator<D> {
    fn run(&mut self, config: &OperatorConfig, read_stream: &mut ReadStream<D>) {
        while let Ok(message) = read_stream.read() {
            println!("Recieved message: {:?}", message);
        }
    }
}

The examples in ExtractStream show how to pull data from a stream in the driver.

Implementations

impl<D: Data> ReadStream<D>

pub fn is_closed(&self) -> bool

Returns true if a top watermark message was sent or the ReadStream failed to set up.

pub fn try_read(&mut self) -> Result<Message<D>, TryReadError>

Non-blocking read from the ReadStream.

Returns the Message available on the ReadStream, or an Empty if no message is available.

pub fn read(&mut self) -> Result<Message<D>, ReadError>

Blocking read from the ReadStream.

Returns the Message available on the ReadStream.

pub fn id(&self) -> StreamId

Get the ID given to the stream by the constructor.

pub fn name(&self) -> String

Get the name of the stream.

Trait Implementations

impl<T: Data> Send for ReadStream<T>

impl<T: Data> Sync for ReadStream<T>