Interface ScatteringByteChannel
- All Superinterfaces:
AutoCloseable
,Channel
,Closeable
,ReadableByteChannel
- All Known Implementing Classes:
DatagramChannel
,FileChannel
,Pipe.SourceChannel
,SocketChannel
A scattering read operation reads, in a single invocation, a
sequence of bytes into one or more of a given sequence of buffers.
Scattering reads are often useful when implementing network protocols or
file formats that, for example, group data into segments consisting of one
or more fixed-length headers followed by a variable-length body. Similar
gathering write operations are defined in the GatheringByteChannel
interface.
- Since:
- 1.4
-
Method Summary
Modifier and TypeMethodDescriptionlong
read
(ByteBuffer[] dsts) Reads a sequence of bytes from this channel into the given buffers.long
read
(ByteBuffer[] dsts, int offset, int length) Reads a sequence of bytes from this channel into a subsequence of the given buffers.Methods declared in interface java.nio.channels.ReadableByteChannel
read
-
Method Details
-
read
Reads a sequence of bytes from this channel into a subsequence of the given buffers.An invocation of this method attempts to read up to r bytes from this channel, where r is the total number of bytes remaining in the specified subsequence of the given buffer array, that is,
dsts[offset].remaining() + dsts[offset+1].remaining() + ... + dsts[offset+length-1].remaining()
Suppose that a byte sequence of length n is read, where
0
<=
n<=
r. Up to the firstdsts[offset].remaining()
bytes of this sequence are transferred into bufferdsts[offset]
, up to the nextdsts[offset+1].remaining()
bytes are transferred into bufferdsts[offset+1]
, and so forth, until the entire byte sequence is transferred into the given buffers. As many bytes as possible are transferred into each buffer, hence the final position of each updated buffer, except the last updated buffer, is guaranteed to be equal to that buffer's limit.This method may be invoked at any time. If another thread has already initiated a read operation upon this channel, however, then an invocation of this method will block until the first operation is complete.
- Parameters:
dsts
- The buffers into which bytes are to be transferredoffset
- The offset within the buffer array of the first buffer into which bytes are to be transferred; must be non-negative and no larger thandsts.length
length
- The maximum number of buffers to be accessed; must be non-negative and no larger thandsts.length
-offset
- Returns:
- The number of bytes read, possibly zero,
or
-1
if the channel has reached end-of-stream - Throws:
IndexOutOfBoundsException
- If the preconditions on theoffset
andlength
parameters do not holdIllegalArgumentException
- If any of the buffers is read-onlyNonReadableChannelException
- If this channel was not opened for readingClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel while the read operation is in progressClosedByInterruptException
- If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt statusIOException
- If some other I/O error occurs
-
read
Reads a sequence of bytes from this channel into the given buffers.An invocation of this method of the form
c.read(dsts)
behaves in exactly the same manner as the invocationc.read(dsts, 0, dsts.length);
- Parameters:
dsts
- The buffers into which bytes are to be transferred- Returns:
- The number of bytes read, possibly zero,
or
-1
if the channel has reached end-of-stream - Throws:
IllegalArgumentException
- If any of the buffers is read-onlyNonReadableChannelException
- If this channel was not opened for readingClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel while the read operation is in progressClosedByInterruptException
- If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt statusIOException
- If some other I/O error occurs
-