AsyncFile (Vert.x Stack - Docs 4.1.8 API)

All Superinterfaces:

ReadStream<Buffer>, StreamBase, WriteStream<Buffer>
```
public interface AsyncFile
extends ReadStream<Buffer>, WriteStream<Buffer>
```
Represents a file on the file-system which can be read from, or written to asynchronously.
This class also implements ReadStream and WriteStream. This allows the data to be piped to and from other streams, e.g. an HttpClientRequest instance, using the Pipe class

Author:

Tim Fox

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`Future<Void>`	`close()` Close the file.
`void`	`close(Handler<AsyncResult<Void>> handler)` Close the file.
`AsyncFile`	`drainHandler(Handler<Void> handler)` Set a drain handler on the stream.
`AsyncFile`	`endHandler(Handler<Void> endHandler)` Set an end handler.
`AsyncFile`	`exceptionHandler(Handler<Throwable> handler)` Set an exception handler on the read stream.
`AsyncFile`	`fetch(long amount)` Fetch the specified `amount` of elements.
`Future<Void>`	`flush()` Flush any writes made to this file to underlying persistent storage.
`AsyncFile`	`flush(Handler<AsyncResult<Void>> handler)` Same as `flush()` but the handler will be called when the flush is complete or if an error occurs
`long`	`getReadLength()`
`long`	`getWritePos()`
`AsyncFile`	`handler(Handler<Buffer> handler)` Set a data handler.
`AsyncFile`	`pause()` Pause the `ReadStream`, it sets the buffer in `fetch` mode and clears the actual demand.
`Future<Buffer>`	`read(Buffer buffer, int offset, long position, int length)` Like `read(Buffer, int, long, int, Handler)` but returns a `Future` of the asynchronous result
`AsyncFile`	`read(Buffer buffer, int offset, long position, int length, Handler<AsyncResult<Buffer>> handler)` Reads `length` bytes of data from the file at position `position` in the file, asynchronously.
`AsyncFile`	`resume()` Resume reading, and sets the buffer in `flowing` mode.
`AsyncFile`	`setReadBufferSize(int readBufferSize)` Sets the buffer size that will be used to read the data from the file.
`AsyncFile`	`setReadLength(long readLength)` Sets the number of bytes that will be read when using the file as a `ReadStream`.
`AsyncFile`	`setReadPos(long readPos)` Sets the position from which data will be read from when using the file as a `ReadStream`.
`AsyncFile`	`setWritePos(long writePos)` Sets the position from which data will be written when using the file as a `WriteStream`.
`AsyncFile`	`setWriteQueueMaxSize(int maxSize)` Set the maximum size of the write queue to `maxSize`.
`Future<Long>`	`size()`
`default void`	`size(Handler<AsyncResult<Long>> handler)` Like `size()` but the `handler` will be called when the operation is complete or if an error occurs.
`long`	`sizeBlocking()` Like `size()` but blocking.
`Future<Void>`	`write(Buffer buffer, long position)` Like `write(Buffer, long, Handler)` but returns a `Future` of the asynchronous result
`void`	`write(Buffer buffer, long position, Handler<AsyncResult<Void>> handler)` Write a `Buffer` to the file at position `position` in the file, asynchronously.

Methods inherited from interface io.vertx.core.streams.ReadStream
pipe, pipeTo, pipeTo

Methods inherited from interface io.vertx.core.streams.WriteStream
end, end, end, end, write, write, writeQueueFull

- Method Detail
  - handler
```
AsyncFile handler(Handler<Buffer> handler)
```
    Description copied from interface: ReadStream
    
    Set a data handler. As data is read, the handler will be called with the data.
    
    Specified by:
    
    handler in interface ReadStream<Buffer>
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - pause
```
AsyncFile pause()
```
    Description copied from interface: ReadStream
    
    Pause the ReadStream, it sets the buffer in fetch mode and clears the actual demand.
    While it's paused, no data will be sent to the data handler.
    
    Specified by:
    
    pause in interface ReadStream<Buffer>
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - resume
```
AsyncFile resume()
```
    Description copied from interface: ReadStream
    
    Resume reading, and sets the buffer in flowing mode.
    If the ReadStream has been paused, reading will recommence on it.
    
    Specified by:
    
    resume in interface ReadStream<Buffer>
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - endHandler
```
AsyncFile endHandler(Handler<Void> endHandler)
```
    Description copied from interface: ReadStream
    
    Set an end handler. Once the stream has ended, and there is no more data to be read, this handler will be called.
    
    Specified by:
    
    endHandler in interface ReadStream<Buffer>
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - setWriteQueueMaxSize
```
AsyncFile setWriteQueueMaxSize(int maxSize)
```
    Description copied from interface: WriteStream
    
    Set the maximum size of the write queue to maxSize. You will still be able to write to the stream even if there is more than maxSize items in the write queue. This is used as an indicator by classes such as Pipe to provide flow control.
    The value is defined by the implementation of the stream, e.g in bytes for a NetSocket, etc...
    
    Specified by:
    
    setWriteQueueMaxSize in interface WriteStream<Buffer>
    
    Parameters:
    
    maxSize - the max size of the write stream
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - drainHandler
```
AsyncFile drainHandler(Handler<Void> handler)
```
    Description copied from interface: WriteStream
    
    Set a drain handler on the stream. If the write queue is full, then the handler will be called when the write queue is ready to accept buffers again. See Pipe for an example of this being used.
    The stream implementation defines when the drain handler, for example it could be when the queue size has been reduced to maxSize / 2.
    
    Specified by:
    
    drainHandler in interface WriteStream<Buffer>
    
    Parameters:
    
    handler - the handler
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - exceptionHandler
```
AsyncFile exceptionHandler(Handler<Throwable> handler)
```
    Description copied from interface: ReadStream
    
    Set an exception handler on the read stream.
    
    Specified by:
    
    exceptionHandler in interface ReadStream<Buffer>
    
    Specified by:
    
    exceptionHandler in interface StreamBase
    
    Specified by:
    
    exceptionHandler in interface WriteStream<Buffer>
    
    Parameters:
    
    handler - the exception handler
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - fetch
```
AsyncFile fetch(long amount)
```
    Description copied from interface: ReadStream
    
    Fetch the specified amount of elements. If the ReadStream has been paused, reading will recommence with the specified amount of items, otherwise the specified amount will be added to the current stream demand.
    
    Specified by:
    
    fetch in interface ReadStream<Buffer>
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - close
```
Future<Void> close()
```
    Close the file. The actual close happens asynchronously.
    
    Returns:
    
    a future completed with the result
  - close
```
void close(Handler<AsyncResult<Void>> handler)
```
    Close the file. The actual close happens asynchronously. The handler will be called when the close is complete, or an error occurs.
    
    Parameters:
    
    handler - the handler
  - write
```
void write(Buffer buffer,
           long position,
           Handler<AsyncResult<Void>> handler)
```
    Write a Buffer to the file at position position in the file, asynchronously.
    If position lies outside of the current size of the file, the file will be enlarged to encompass it.
    When multiple writes are invoked on the same file there are no guarantees as to order in which those writes actually occur
    The handler will be called when the write is complete, or if an error occurs.
    
    Parameters:
    
    buffer - the buffer to write
    
    position - the position in the file to write it at
    
    handler - the handler to call when the write is complete
  - write
```
Future<Void> write(Buffer buffer,
                   long position)
```
    Like write(Buffer, long, Handler) but returns a Future of the asynchronous result
  - read
```
AsyncFile read(Buffer buffer,
               int offset,
               long position,
               int length,
               Handler<AsyncResult<Buffer>> handler)
```
    Reads length bytes of data from the file at position position in the file, asynchronously.
    The read data will be written into the specified Buffer buffer at position offset.
    If data is read past the end of the file then zero bytes will be read.
    When multiple reads are invoked on the same file there are no guarantees as to order in which those reads actually occur.
    The handler will be called when the close is complete, or if an error occurs.
    
    Parameters:
    
    buffer - the buffer to read into
    
    offset - the offset into the buffer where the data will be read
    
    position - the position in the file where to start reading
    
    length - the number of bytes to read
    
    handler - the handler to call when the write is complete
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - read
```
Future<Buffer> read(Buffer buffer,
                    int offset,
                    long position,
                    int length)
```
    Like read(Buffer, int, long, int, Handler) but returns a Future of the asynchronous result
  - flush
```
Future<Void> flush()
```
    Flush any writes made to this file to underlying persistent storage.
    If the file was opened with flush set to true then calling this method will have no effect.
    The actual flush will happen asynchronously.
    
    Returns:
    
    a future completed with the result
  - flush
```
AsyncFile flush(Handler<AsyncResult<Void>> handler)
```
    Same as flush() but the handler will be called when the flush is complete or if an error occurs
  - setReadPos
```
AsyncFile setReadPos(long readPos)
```
    Sets the position from which data will be read from when using the file as a ReadStream.
    
    Parameters:
    
    readPos - the position in the file
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - setReadLength
```
AsyncFile setReadLength(long readLength)
```
    Sets the number of bytes that will be read when using the file as a ReadStream.
    
    Parameters:
    
    readLength - the bytes that will be read from the file
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - getReadLength
```
long getReadLength()
```
    Returns:
    
    the number of bytes that will be read when using the file as a ReadStream
  - setWritePos
```
AsyncFile setWritePos(long writePos)
```
    Sets the position from which data will be written when using the file as a WriteStream.
    
    Parameters:
    
    writePos - the position in the file
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - getWritePos
```
long getWritePos()
```
    Returns:
    
    the current write position the file is at
  - setReadBufferSize
```
AsyncFile setReadBufferSize(int readBufferSize)
```
    Sets the buffer size that will be used to read the data from the file. Changing this value will impact how much the data will be read at a time from the file system.
    
    Parameters:
    
    readBufferSize - the buffer size
    
    Returns:
    
    a reference to this, so the API can be used fluently
  - sizeBlocking
```
long sizeBlocking()
```
    Like size() but blocking.
    
    Throws:
    
    FileSystemException - if an error occurs
  - size
```
default void size(Handler<AsyncResult<Long>> handler)
```
    Like size() but the handler will be called when the operation is complete or if an error occurs.
  - size
```
Future<Long> size()
```
    Returns:
    
    the size of the file

Interface AsyncFile

Method Summary

Methods inherited from interface io.vertx.core.streams.ReadStream

Methods inherited from interface io.vertx.core.streams.WriteStream

Method Detail

handler

pause

resume

endHandler

setWriteQueueMaxSize

drainHandler

exceptionHandler

fetch

close

close

write

write

read

read

flush

flush

setReadPos

setReadLength

getReadLength

setWritePos

getWritePos

setReadBufferSize

sizeBlocking

size

size