FileRegion (Netty/Transport 4.2.4.Final API)

All Superinterfaces:

io.netty.util.ReferenceCounted

All Known Implementing Classes:

DefaultFileRegion
```
public interface FileRegion
extends io.netty.util.ReferenceCounted
```
A region of a file that is sent via a Channel which supports zero-copy file transfer.
Upgrade your JDK / JRE
FileChannel.transferTo(long, long, WritableByteChannel) has at least four known bugs in the old versions of Sun JDK and perhaps its derived ones. Please upgrade your JDK to 1.6.0_18 or later version if you are going to use zero-copy file transfer.
- 5103988 - FileChannel.transferTo() should return -1 for EAGAIN instead throws IOException
- 6253145 - FileChannel.transferTo() on Linux fails when going beyond 2GB boundary
- 6427312 - FileChannel.transferTo() throws IOException "system call interrupted"
- 6470086 - FileChannel.transferTo(2147483647, 1, channel) causes "Value too large" exception
Check your operating system and JDK / JRE
If your operating system (or JDK / JRE) does not support zero-copy file transfer, sending a file with FileRegion might fail or yield worse performance. For example, sending a large file doesn't work well in Windows.
Not all transports support it

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method	Description
`long`	`count()`	Returns the number of bytes to transfer.
`long`	`position()`	Returns the offset in the file where the transfer began.
`FileRegion`	`retain()`
`FileRegion`	`retain(int increment)`
`FileRegion`	`touch()`
`FileRegion`	`touch(Object hint)`
`long`	`transfered()`	Deprecated. Use `transferred()` instead.
`long`	`transferred()`	Returns the bytes which was transferred already.
`long`	`transferTo(WritableByteChannel target, long position)`	Transfers the content of this file region to the specified channel.

Methods inherited from interface io.netty.util.ReferenceCounted
refCnt, release, release

- Method Detail
  - position
```
long position()
```
    Returns the offset in the file where the transfer began.
  - transfered
```
@Deprecated
long transfered()
```
    Deprecated.
    Use transferred() instead.
    
    Returns the bytes which was transferred already.
  - transferred
```
long transferred()
```
    Returns the bytes which was transferred already.
  - count
```
long count()
```
    Returns the number of bytes to transfer.
  - transferTo
```
long transferTo(WritableByteChannel target,
                long position)
         throws IOException
```
    Transfers the content of this file region to the specified channel.
    
    Parameters:
    
    target - the destination of the transfer
    
    position - the relative offset of the file where the transfer begins from. For example, 0 will make the transfer start from position()th byte and count() - 1 will make the last byte of the region transferred.
    
    Throws:
    
    IOException
  - retain
```
FileRegion retain()
```
    Specified by:
    
    retain in interface io.netty.util.ReferenceCounted
  - retain
```
FileRegion retain(int increment)
```
    Specified by:
    
    retain in interface io.netty.util.ReferenceCounted
  - touch
```
FileRegion touch()
```
    Specified by:
    
    touch in interface io.netty.util.ReferenceCounted
  - touch
```
FileRegion touch(Object hint)
```
    Specified by:
    
    touch in interface io.netty.util.ReferenceCounted