Type Parameters:

T - The type of events being sent through this stream.

All Superinterfaces:

java.lang.AutoCloseable
```
public interface EventStreamReader<T>
extends java.lang.AutoCloseable
```
A reader for a stream.
This class is safe to use across threads, but doing so will not increase performance.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`close()`	Close the reader.
`void`	`closeAt(Position position)`	Close the reader at a specific position.
`T`	`fetchEvent(EventPointer pointer)`	Re-read an event that was previously read, by passing the pointer returned from `EventRead.getEventPointer()`.
`ReaderConfig`	`getConfig()`	Gets the configuration that this reader was created with.
`TimeWindow`	`getCurrentTimeWindow(Stream stream)`	Returns a window which represents the range of time that this reader is currently reading as provided by writers via the `EventStreamWriter.noteTime(long)` API.
`EventRead<T>`	`readNextEvent(long timeoutMillis)`	Gets the next event in the stream.

- Method Detail
  - getCurrentTimeWindow
```
TimeWindow getCurrentTimeWindow(Stream stream)
```
    Returns a window which represents the range of time that this reader is currently reading as provided by writers via the EventStreamWriter.noteTime(long) API. If no writers were providing timestamps at the current position in the stream `null` will be returned.
    
    Parameters:
    
    stream - the stream to obtain a time window for.
    
    Returns:
    
    A TimeWindow which bounds the current location in the stream, or null if one cannot be established.
  - readNextEvent
```
EventRead<T> readNextEvent(long timeoutMillis)
                    throws ReinitializationRequiredException,
                           TruncatedDataException
```
    Gets the next event in the stream. If there are no events currently available this will block up for timeoutMillis waiting for them to arrive. If none do, an EventRead will be returned with null for EventRead.getEvent(). (As well as for most other fields) An EventRead with null for EventRead.getEvent() is returned when the Reader has read all events up to the configured end StreamCut specified using ReaderGroupConfig.
    Note: An EventRead with null for EventRead.getEvent() is returned when EventRead.isCheckpoint() is true. A null can also be returned due to delays in the Pravega cluster.
    
    Parameters:
    
    timeoutMillis - An upper bound on how long the call may block before returning null.
    
    Returns:
    
    An instance of EventRead, which contains the next event in the stream. In the case the timeoutMillis is reached, EventRead.getEvent() returns null.
    
    Throws:
    
    ReinitializationRequiredException - Is thrown in the event that ReaderGroup.resetReaderGroup(ReaderGroupConfig) was called which requires readers to be reinitialized.
    
    TruncatedDataException - if the data that would be read next has been truncated away and can no longer be read. (If following this readNextEvent is called again it will resume from the next available event.)
  - getConfig
```
ReaderConfig getConfig()
```
    Gets the configuration that this reader was created with.
    
    Returns:
    
    Reader configuration
  - fetchEvent
```
T fetchEvent(EventPointer pointer)
      throws io.pravega.client.segment.impl.NoSuchEventException
```
    Re-read an event that was previously read, by passing the pointer returned from EventRead.getEventPointer(). This does not affect the current position of the reader.
    This is a blocking call. Passing invalid offsets has undefined behavior.
    
    Parameters:
    
    pointer - The pointer object to enable a random read of the event.
    
    Returns:
    
    The event at the position specified by the provided pointer or null if the event has been deleted.
    
    Throws:
    
    io.pravega.client.segment.impl.NoSuchEventException - Reader was not able to fetch the event.
  - close
```
void close()
```
    Close the reader. No further actions may be performed. If this reader is part of a reader group, this will automatically invoke ReaderGroup.readerOffline(String, Position)
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
    
    See Also:
    
    AutoCloseable.close()
  - closeAt
```
void closeAt(Position position)
```
    Close the reader at a specific position. No further actions may be performed. If this reader is part of a ReaderGroup, this will automatically invoke ReaderGroup.readerOffline(String, Position) with the supplied position.
    
    Parameters:
    
    position - Position to use while reporting readerOffline on the ReaderGroup.

Interface EventStreamReader<T>

Method Summary

Method Detail

getCurrentTimeWindow

readNextEvent

getConfig

fetchEvent

close

closeAt