Class SocketWrapperBase<E>

java.lang.Object
org.apache.tomcat.util.net.SocketWrapperBase<E>
Direct Known Subclasses:
AprEndpoint.AprSocketWrapper, Nio2Endpoint.Nio2SocketWrapper, NioEndpoint.NioSocketWrapper
public abstract class SocketWrapperBase<E> extends Object

  • Field Details

    • sm

      protected static final StringManager sm

    • closed

      protected final AtomicBoolean closed

    • previousIOException

      protected volatile IOException previousIOException

    • localAddr

      protected String localAddr

    • localName

      protected String localName

    • localPort

      protected int localPort

    • remoteAddr

      protected String remoteAddr

    • remoteHost

      protected String remoteHost

    • remotePort

      protected int remotePort

    • socketBufferHandler

      protected volatile SocketBufferHandler socketBufferHandler
      The buffers used for communicating with the socket.

    • bufferedWriteSize

      protected int bufferedWriteSize
      The max size of the individual buffered write buffers

    • nonBlockingWriteBuffer

      protected final WriteBuffer nonBlockingWriteBuffer
      Additional buffer used for non-blocking writes. Non-blocking writes need to return immediately even if the data cannot be written immediately but the socket buffer may not be big enough to hold all of the unwritten data. This structure provides an additional buffer to hold the data until it can be written. Not that while the Servlet API only allows one non-blocking write at a time, due to buffering and the possible need to write HTTP headers, this layer may see multiple writes.

    • readPending

      protected final Semaphore readPending

    • readOperation

      protected volatile SocketWrapperBase<E>.OperationState<?> readOperation

    • writePending

      protected final Semaphore writePending

    • writeOperation

      protected volatile SocketWrapperBase<E>.OperationState<?> writeOperation

    • COMPLETE_WRITE

      public static final SocketWrapperBase.CompletionCheck COMPLETE_WRITE
      This utility CompletionCheck will cause the write to fully write all remaining data. If the operation completes inline, the completion handler will not be called.

    • COMPLETE_WRITE_WITH_COMPLETION

      public static final SocketWrapperBase.CompletionCheck COMPLETE_WRITE_WITH_COMPLETION
      This utility CompletionCheck will cause the write to fully write all remaining data. The completion handler will then be called.

    • READ_DATA

      public static final SocketWrapperBase.CompletionCheck READ_DATA
      This utility CompletionCheck will cause the completion handler to be called once some data has been read. If the operation completes inline, the completion handler will not be called.

    • COMPLETE_READ_WITH_COMPLETION

      public static final SocketWrapperBase.CompletionCheck COMPLETE_READ_WITH_COMPLETION
      This utility CompletionCheck will cause the completion handler to be called once the given buffers are full. The completion handler will then be called.

    • COMPLETE_READ

      public static final SocketWrapperBase.CompletionCheck COMPLETE_READ
      This utility CompletionCheck will cause the completion handler to be called once the given buffers are full. If the operation completes inline, the completion handler will not be called.

  • Constructor Details

  • Method Details

    • getSocket

      public E getSocket()

    • reset

      protected void reset(E closedSocket)

    • getEndpoint

      protected AbstractEndpoint<E,?> getEndpoint()

    • getLock

      public Lock getLock()

    • getCurrentProcessor

      public Object getCurrentProcessor()

    • setCurrentProcessor

      public void setCurrentProcessor(Object currentProcessor)

    • takeCurrentProcessor

      public Object takeCurrentProcessor()

    • execute

      public void execute(Runnable runnable)
      Transfers processing to a container thread.
      Parameters:
      runnable - The actions to process on a container thread
      Throws:
      RejectedExecutionException - If the runnable cannot be executed

    • getError

      public IOException getError()

    • setError

      public void setError(IOException error)

    • checkError

      public void checkError() throws IOException
      Throws:
      IOException

    • isUpgraded

      @Deprecated public boolean isUpgraded()
      Deprecated.
      Unused. Will be removed in Tomcat 10.
      Returns:
      true if the connection has been upgraded.

    • setUpgraded

      @Deprecated public void setUpgraded(boolean upgraded)
      Deprecated.
      Unused. Will be removed in Tomcat 10.
      Parameters:
      upgraded - true if the connection has been upgraded.

    • isSecure

      @Deprecated public boolean isSecure()
      Deprecated.
      Unused. Will be removed in Tomcat 10.
      Returns:
      true if the connection uses TLS

    • setSecure

      @Deprecated public void setSecure(boolean secure)
      Deprecated.
      Unused. Will be removed in Tomcat 10.
      Parameters:
      secure - true if the connection uses TLS

    • getNegotiatedProtocol

      public String getNegotiatedProtocol()

    • setNegotiatedProtocol

      public void setNegotiatedProtocol(String negotiatedProtocol)

    • setReadTimeout

      public void setReadTimeout(long readTimeout)
      Set the timeout for reading. Values of zero or less will be changed to -1.
      Parameters:
      readTimeout - The timeout in milliseconds. A value of -1 indicates an infinite timeout.

    • getReadTimeout

      public long getReadTimeout()

    • setWriteTimeout

      public void setWriteTimeout(long writeTimeout)
      Set the timeout for writing. Values of zero or less will be changed to -1.
      Parameters:
      writeTimeout - The timeout in milliseconds. A value of zero or less indicates an infinite timeout.

    • getWriteTimeout

      public long getWriteTimeout()

    • setKeepAliveLeft

      public void setKeepAliveLeft(int keepAliveLeft)

    • decrementKeepAlive

      public int decrementKeepAlive()

    • getRemoteHost

      public String getRemoteHost()

    • populateRemoteHost

      protected abstract void populateRemoteHost()

    • getRemoteAddr

      public String getRemoteAddr()

    • populateRemoteAddr

      protected abstract void populateRemoteAddr()

    • getRemotePort

      public int getRemotePort()

    • populateRemotePort

      protected abstract void populateRemotePort()

    • getLocalName

      public String getLocalName()

    • populateLocalName

      protected abstract void populateLocalName()

    • getLocalAddr

      public String getLocalAddr()

    • populateLocalAddr

      protected abstract void populateLocalAddr()

    • getLocalPort

      public int getLocalPort()

    • populateLocalPort

      protected abstract void populateLocalPort()

    • getSocketBufferHandler

      public SocketBufferHandler getSocketBufferHandler()

    • hasDataToRead

      public boolean hasDataToRead()

    • hasDataToWrite

      public boolean hasDataToWrite()

    • isReadyForWrite

      public boolean isReadyForWrite()
      Checks to see if there are any writes pending and if there are calls registerWriteInterest() to trigger a callback once the pending writes have completed.

      Note: Once this method has returned false it MUST NOT be called again until the pending write has completed and the callback has been fired. TODO: Modify registerWriteInterest() so the above restriction is enforced there rather than relying on the caller.

      Returns:
      true if no writes are pending and data can be written otherwise false

    • canWrite

      public boolean canWrite()

    • toString

      public String toString()
      Overridden for debug purposes. No guarantees are made about the format of this message which may vary significantly between point releases.

      Overrides:
      toString in class Object

    • read

      public abstract int read(boolean block, byte[] b, int off, int len) throws IOException
      Throws:
      IOException

    • read

      public abstract int read(boolean block, ByteBuffer to) throws IOException
      Throws:
      IOException

    • isReadyForRead

      public abstract boolean isReadyForRead() throws IOException
      Throws:
      IOException

    • setAppReadBufHandler

      public abstract void setAppReadBufHandler(ApplicationBufferHandler handler)

    • populateReadBuffer

      protected int populateReadBuffer(byte[] b, int off, int len)

    • populateReadBuffer

      protected int populateReadBuffer(ByteBuffer to)

    • unRead

      public void unRead(ByteBuffer returnedInput)
      Return input that has been read to the input buffer for re-reading by the correct component. There are times when a component may read more data than it needs before it passes control to another component. One example of this is during HTTP upgrade. If an (arguably misbehaving client) sends data associated with the upgraded protocol before the HTTP upgrade completes, the HTTP handler may read it. This method provides a way for that data to be returned so it can be processed by the correct component.
      Parameters:
      returnedInput - The input to return to the input buffer.

    • close

      public void close()
      Close the socket wrapper.

    • doClose

      protected abstract void doClose()
      Perform the actual close. The closed atomic boolean guarantees this will be called only once per wrapper.

    • isClosed

      public boolean isClosed()
      Returns:
      true if the wrapper has been closed

    • write

      public final void write(boolean block, byte[] buf, int off, int len) throws IOException
      Writes the provided data to the socket write buffer. If the socket write buffer fills during the write, the content of the socket write buffer is written to the network and this method starts to fill the socket write buffer again. Depending on the size of the data to write, there may be multiple writes to the network.

      Non-blocking writes must return immediately and the byte array holding the data to be written must be immediately available for re-use. It may not be possible to write sufficient data to the network to allow this to happen. In this case data that cannot be written to the network and cannot be held by the socket buffer is stored in the non-blocking write buffer.

      Note: There is an implementation assumption that, before switching from non-blocking writes to blocking writes, any data remaining in the non-blocking write buffer will have been written to the network.

      Parameters:
      block - true if a blocking write should be used, otherwise a non-blocking write will be used
      buf - The byte array containing the data to be written
      off - The offset within the byte array of the data to be written
      len - The length of the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • write

      public final void write(boolean block, ByteBuffer from) throws IOException
      Writes the provided data to the socket write buffer. If the socket write buffer fills during the write, the content of the socket write buffer is written to the network and this method starts to fill the socket write buffer again. Depending on the size of the data to write, there may be multiple writes to the network.

      Non-blocking writes must return immediately and the ByteBuffer holding the data to be written must be immediately available for re-use. It may not be possible to write sufficient data to the network to allow this to happen. In this case data that cannot be written to the network and cannot be held by the socket buffer is stored in the non-blocking write buffer.

      Note: There is an implementation assumption that, before switching from non-blocking writes to blocking writes, any data remaining in the non-blocking write buffer will have been written to the network.

      Parameters:
      block - true if a blocking write should be used, otherwise a non-blocking write will be used
      from - The ByteBuffer containing the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • writeBlocking

      protected void writeBlocking(byte[] buf, int off, int len) throws IOException
      Writes the provided data to the socket write buffer. If the socket write buffer fills during the write, the content of the socket write buffer is written to the network using a blocking write. Once that blocking write is complete, this method starts to fill the socket write buffer again. Depending on the size of the data to write, there may be multiple writes to the network. On completion of this method there will always be space remaining in the socket write buffer.
      Parameters:
      buf - The byte array containing the data to be written
      off - The offset within the byte array of the data to be written
      len - The length of the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • writeBlocking

      protected void writeBlocking(ByteBuffer from) throws IOException
      Writes the provided data to the socket write buffer. If the socket write buffer fills during the write, the content of the socket write buffer is written to the network using a blocking write. Once that blocking write is complete, this method starts to fill the socket write buffer again. Depending on the size of the data to write, there may be multiple writes to the network. On completion of this method there will always be space remaining in the socket write buffer.
      Parameters:
      from - The ByteBuffer containing the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • writeNonBlocking

      protected void writeNonBlocking(byte[] buf, int off, int len) throws IOException
      Transfers the data to the socket write buffer (writing that data to the socket if the buffer fills up using a non-blocking write) until either all the data has been transferred and space remains in the socket write buffer or a non-blocking write leaves data in the socket write buffer. After an incomplete write, any data remaining to be transferred to the socket write buffer will be copied to the socket write buffer. If the remaining data is too big for the socket write buffer, the socket write buffer will be filled and the additional data written to the non-blocking write buffer.
      Parameters:
      buf - The byte array containing the data to be written
      off - The offset within the byte array of the data to be written
      len - The length of the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • writeNonBlocking

      protected void writeNonBlocking(ByteBuffer from) throws IOException
      Transfers the data to the socket write buffer (writing that data to the socket if the buffer fills up using a non-blocking write) until either all the data has been transferred and space remains in the socket write buffer or a non-blocking write leaves data in the socket write buffer. After an incomplete write, any data remaining to be transferred to the socket write buffer will be copied to the socket write buffer. If the remaining data is too big for the socket write buffer, the socket write buffer will be filled and the additional data written to the non-blocking write buffer.
      Parameters:
      from - The ByteBuffer containing the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • writeNonBlockingInternal

      protected void writeNonBlockingInternal(ByteBuffer from) throws IOException
      Separate method so it can be re-used by the socket write buffer to write data to the network
      Parameters:
      from - The ByteBuffer containing the data to be written
      Throws:
      IOException - If an IO error occurs during the write

    • flush

      public boolean flush(boolean block) throws IOException
      Writes as much data as possible from any that remains in the buffers.
      Parameters:
      block - true if a blocking write should be used, otherwise a non-blocking write will be used
      Returns:
      true if data remains to be flushed after this method completes, otherwise false. In blocking mode therefore, the return value should always be false
      Throws:
      IOException - If an IO error occurs during the write

    • flushBlocking

      protected void flushBlocking() throws IOException
      Writes all remaining data from the buffers and blocks until the write is complete.
      Throws:
      IOException - If an IO error occurs during the write

    • flushNonBlocking

      protected abstract boolean flushNonBlocking() throws IOException
      Writes as much data as possible from any that remains in the buffers.
      Returns:
      true if data remains to be flushed after this method completes, otherwise false.
      Throws:
      IOException - If an IO error occurs during the write

    • doWrite

      protected void doWrite(boolean block) throws IOException
      Write the contents of the socketWriteBuffer to the socket. For blocking writes either then entire contents of the buffer will be written or an IOException will be thrown. Partial blocking writes will not occur.
      Parameters:
      block - Should the write be blocking or not?
      Throws:
      IOException - If an I/O error such as a timeout occurs during the write

    • doWrite

      protected abstract void doWrite(boolean block, ByteBuffer from) throws IOException
      Write the contents of the ByteBuffer to the socket. For blocking writes either then entire contents of the buffer will be written or an IOException will be thrown. Partial blocking writes will not occur.
      Parameters:
      block - Should the write be blocking or not?
      from - the ByteBuffer containing the data to be written
      Throws:
      IOException - If an I/O error such as a timeout occurs during the write

    • processSocket

      public void processSocket(SocketEvent socketStatus, boolean dispatch)

    • registerReadInterest

      public abstract void registerReadInterest()

    • registerWriteInterest

      public abstract void registerWriteInterest()

    • createSendfileData

      public abstract SendfileDataBase createSendfileData(String filename, long pos, long length)

    • processSendfile

      public abstract SendfileState processSendfile(SendfileDataBase sendfileData)
      Starts the sendfile process. It is expected that if the sendfile process does not complete during this call and does not report an error, that the caller will not add the socket to the poller (or equivalent). That is the responsibility of this method.
      Parameters:
      sendfileData - Data representing the file to send
      Returns:
      The state of the sendfile process after the first write.

    • doClientAuth

      public abstract void doClientAuth(SSLSupport sslSupport) throws IOException
      Require the client to perform CLIENT-CERT authentication if it hasn't already done so.
      Parameters:
      sslSupport - The SSL/TLS support instance currently being used by the connection that may need updating after the client authentication
      Throws:
      IOException - If authentication is required then there will be I/O with the client and this exception will be thrown if that goes wrong

    • getSslSupport

      @Deprecated public SSLSupport getSslSupport(String clientCertProvider)
      Deprecated.
      Will be removed in Tomcat 10.1.x onwards
      Obtain an SSLSupport instance for this socket.
      Parameters:
      clientCertProvider - The name of the client certificate provider to use. Only used by APR/native.
      Returns:
      An SSLSupport instance for this socket.

    • getSslSupport

      public abstract SSLSupport getSslSupport()
      Obtain an SSLSupport instance for this socket.
      Returns:
      An SSLSupport instance for this socket.

    • hasAsyncIO

      public boolean hasAsyncIO()
      Allows using NIO2 style read/write.
      Returns:
      true if the connector has the capability enabled

    • needSemaphores

      public boolean needSemaphores()
      Allows indicating if the connector needs semaphores.
      Returns:
      This default implementation always returns false

    • hasPerOperationTimeout

      public boolean hasPerOperationTimeout()
      Allows indicating if the connector supports per operation timeout.
      Returns:
      This default implementation always returns false

    • isReadPending

      public boolean isReadPending()
      Allows checking if an asynchronous read operation is currently pending.
      Returns:
      true if the endpoint supports asynchronous IO and a read operation is being processed asynchronously

    • isWritePending

      public boolean isWritePending()
      Allows checking if an asynchronous write operation is currently pending.
      Returns:
      true if the endpoint supports asynchronous IO and a write operation is being processed asynchronously

    • awaitReadComplete

      @Deprecated public boolean awaitReadComplete(long timeout, TimeUnit unit)
      Deprecated.
      If an asynchronous read operation is pending, this method will block until the operation completes, or the specified amount of time has passed.
      Parameters:
      timeout - The maximum amount of time to wait
      unit - The unit for the timeout
      Returns:
      true if the read operation is complete, false if the operation is still pending and the specified timeout has passed

    • awaitWriteComplete

      @Deprecated public boolean awaitWriteComplete(long timeout, TimeUnit unit)
      Deprecated.
      If an asynchronous write operation is pending, this method will block until the operation completes, or the specified amount of time has passed.
      Parameters:
      timeout - The maximum amount of time to wait
      unit - The unit for the timeout
      Returns:
      true if the read operation is complete, false if the operation is still pending and the specified timeout has passed

    • read

      public final <A> SocketWrapperBase.CompletionState read(long timeout, TimeUnit unit, A attachment, CompletionHandler<Long, ? super A> handler, ByteBuffer... dsts)
      Scatter read. The completion handler will be called once some data has been read or an error occurred. The default NIO2 behavior is used: the completion handler will be called as soon as some data has been read, even if the read has completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      timeout - timeout duration for the read
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      handler - to call when the IO is complete
      dsts - buffers
      Returns:
      the completion state (done, done inline, or still pending)

    • read

      public final <A> SocketWrapperBase.CompletionState read(SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler, ByteBuffer... dsts)
      Scatter read. The completion handler will be called once some data has been read or an error occurred. If a CompletionCheck object has been provided, the completion handler will only be called if the callHandler method returned true. If no CompletionCheck object has been provided, the default NIO2 behavior is used: the completion handler will be called as soon as some data has been read, even if the read has completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      block - is the blocking mode that will be used for this operation
      timeout - timeout duration for the read
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      check - for the IO operation completion
      handler - to call when the IO is complete
      dsts - buffers
      Returns:
      the completion state (done, done inline, or still pending)

    • read

      public final <A> SocketWrapperBase.CompletionState read(ByteBuffer[] dsts, int offset, int length, SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler)
      Scatter read. The completion handler will be called once some data has been read or an error occurred. If a CompletionCheck object has been provided, the completion handler will only be called if the callHandler method returned true. If no CompletionCheck object has been provided, the default NIO2 behavior is used: the completion handler will be called as soon as some data has been read, even if the read has completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      dsts - buffers
      offset - in the buffer array
      length - in the buffer array
      block - is the blocking mode that will be used for this operation
      timeout - timeout duration for the read
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      check - for the IO operation completion
      handler - to call when the IO is complete
      Returns:
      the completion state (done, done inline, or still pending)

    • write

      public final <A> SocketWrapperBase.CompletionState write(long timeout, TimeUnit unit, A attachment, CompletionHandler<Long, ? super A> handler, ByteBuffer... srcs)
      Gather write. The completion handler will be called once some data has been written or an error occurred. The default NIO2 behavior is used: the completion handler will be called, even if the write is incomplete and data remains in the buffers, or if the write completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      timeout - timeout duration for the write
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      handler - to call when the IO is complete
      srcs - buffers
      Returns:
      the completion state (done, done inline, or still pending)

    • write

      public final <A> SocketWrapperBase.CompletionState write(SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler, ByteBuffer... srcs)
      Gather write. The completion handler will be called once some data has been written or an error occurred. If a CompletionCheck object has been provided, the completion handler will only be called if the callHandler method returned true. If no CompletionCheck object has been provided, the default NIO2 behavior is used: the completion handler will be called, even if the write is incomplete and data remains in the buffers, or if the write completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      block - is the blocking mode that will be used for this operation
      timeout - timeout duration for the write
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      check - for the IO operation completion
      handler - to call when the IO is complete
      srcs - buffers
      Returns:
      the completion state (done, done inline, or still pending)

    • write

      public final <A> SocketWrapperBase.CompletionState write(ByteBuffer[] srcs, int offset, int length, SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler)
      Gather write. The completion handler will be called once some data has been written or an error occurred. If a CompletionCheck object has been provided, the completion handler will only be called if the callHandler method returned true. If no CompletionCheck object has been provided, the default NIO2 behavior is used: the completion handler will be called, even if the write is incomplete and data remains in the buffers, or if the write completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      srcs - buffers
      offset - in the buffer array
      length - in the buffer array
      block - is the blocking mode that will be used for this operation
      timeout - timeout duration for the write
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      check - for the IO operation completion
      handler - to call when the IO is complete
      Returns:
      the completion state (done, done inline, or still pending)

    • vectoredOperation

      protected final <A> SocketWrapperBase.CompletionState vectoredOperation(boolean read, ByteBuffer[] buffers, int offset, int length, SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler)
      Vectored operation. The completion handler will be called once the operation is complete or an error occurred. If a CompletionCheck object has been provided, the completion handler will only be called if the callHandler method returned true. If no CompletionCheck object has been provided, the default NIO2 behavior is used: the completion handler will be called, even if the operation is incomplete, or if the operation completed inline.
      Type Parameters:
      A - The attachment type
      Parameters:
      read - true if the operation is a read, false if it is a write
      buffers - buffers
      offset - in the buffer array
      length - in the buffer array
      block - is the blocking mode that will be used for this operation
      timeout - timeout duration for the write
      unit - units for the timeout duration
      attachment - an object to attach to the I/O operation that will be used when calling the completion handler
      check - for the IO operation completion
      handler - to call when the IO is complete
      Returns:
      the completion state (done, done inline, or still pending)

    • newOperationState

      protected abstract <A> SocketWrapperBase<E>.OperationState<A> newOperationState(boolean read, ByteBuffer[] buffers, int offset, int length, SocketWrapperBase.BlockingMode block, long timeout, TimeUnit unit, A attachment, SocketWrapperBase.CompletionCheck check, CompletionHandler<Long, ? super A> handler, Semaphore semaphore, SocketWrapperBase<E>.VectoredIOCompletionHandler<A> completion)

    • transfer

      protected static int transfer(byte[] from, int offset, int length, ByteBuffer to)

    • transfer

      protected static int transfer(ByteBuffer from, ByteBuffer to)

    • buffersArrayHasRemaining

      protected static boolean buffersArrayHasRemaining(ByteBuffer[] buffers, int offset, int length)