Package org.jboss.netty.channel
Interface FileRegion
- All Superinterfaces:
ExternalResourceReleasable
- All Known Implementing Classes:
DefaultFileRegion
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 withFileRegion
might fail or yield worse
performance. For example, sending a large file doesn't work well in Windows.
Not all transports support it
Currently, the NIO transport is the only transport that supportsFileRegion
.
Attempting to write a FileRegion
to non-NIO Channel
will trigger
a ClassCastException
or a similar exception.-
Method Summary
Modifier and TypeMethodDescriptionlong
getCount()
Returns the number of bytes to transfer.long
Returns the offset in the file where the transfer began.long
transferTo
(WritableByteChannel target, long position) Transfers the content of this file region to the specified channel.Methods inherited from interface org.jboss.netty.util.ExternalResourceReleasable
releaseExternalResources
-
Method Details
-
getPosition
long getPosition()Returns the offset in the file where the transfer began. -
getCount
long getCount()Returns the number of bytes to transfer. -
transferTo
Transfers the content of this file region to the specified channel.- Parameters:
target
- the destination of the transferposition
- the relative offset of the file where the transfer begins from. For example, 0 will make the transfer start fromgetPosition()
th byte andgetCount()
- 1 will make the last byte of the region transferred.- Throws:
IOException
-