Class TransportCursor

java.lang.Object
org.simpleframework.transport.TransportCursor
All Implemented Interfaces:
ByteCursor

public class TransportCursor extends Object implements ByteCursor
The TransportCursor object represents a cursor that can read and buffer data from an underlying transport. If the number of bytes read from the cursor is more than required for the HTTP request then those bytes can be pushed back in to the cursor using the reset method. This will only allow the last read to be reset within the cursor safely.
See Also:
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private byte[]
    This is the buffer used to collect the bytes pushed back.
    private int
    This is the number of bytes that have been pushed back.
    private int
    This is the maximum number of bytes that can be pushed back.
    private int
    This is the mark from the last read from this cursor object.
    private int
    This is the position to read data from the internal buffer.
    private ByteReader
    This is the stream for the bytes read by this cursor object.
  • Constructor Summary

    Constructors
    Constructor
    Description
    Constructor for the TransportCursor object.
    TransportCursor(Transport transport, int size)
    Constructor for the TransportCursor object.
  • Method Summary

    Modifier and Type
    Method
    Description
    private void
    expand(int capacity)
    This is used to ensure that there is enough space in the buffer to allow for more bytes to be added.
    boolean
    Determines whether the cursor is still open.
    boolean
    Determines whether the cursor is ready for reading.
    void
    push(byte[] data)
    Pushes the provided data on to the cursor.
    void
    push(byte[] data, int off, int len)
    Pushes the provided data on to the cursor.
    int
    read(byte[] data)
    Reads a block of bytes from the underlying stream.
    int
    read(byte[] data, int off, int len)
    Reads a block of bytes from the underlying stream.
    int
    Provides the number of bytes that can be read from the stream without blocking.
    int
    reset(int size)
    Moves the cursor backward within the stream.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • reader

      private ByteReader reader
      This is the stream for the bytes read by this cursor object.
    • buffer

      private byte[] buffer
      This is the buffer used to collect the bytes pushed back.
    • count

      private int count
      This is the number of bytes that have been pushed back.
    • mark

      private int mark
      This is the mark from the last read from this cursor object.
    • pos

      private int pos
      This is the position to read data from the internal buffer.
    • limit

      private int limit
      This is the maximum number of bytes that can be pushed back.
  • Constructor Details

    • TransportCursor

      public TransportCursor(Transport transport)
      Constructor for the TransportCursor object. This requires a transport to read the bytes from. By default this will create a buffer of of the specified size to read the input in to which enabled bytes to be buffered internally.
      Parameters:
      transport - this is the underlying transport to use
    • TransportCursor

      public TransportCursor(Transport transport, int size)
      Constructor for the TransportCursor object. This requires a transport to read the bytes from. By default this will create a buffer of of the specified size to read the input in to which enabled bytes to be buffered internally.
      Parameters:
      transport - this is the underlying transport to use
      size - this is the size of the internal buffer to use
  • Method Details

    • isOpen

      public boolean isOpen() throws IOException
      Determines whether the cursor is still open. The cursor is considered open if there are still bytes to read. If there is still bytes buffered and the underlying transport is closed then the cursor is still considered open.
      Specified by:
      isOpen in interface ByteCursor
      Returns:
      true if there is nothing more to be read from this
      Throws:
      IOException
    • isReady

      public boolean isReady() throws IOException
      Determines whether the cursor is ready for reading. When the cursor is ready then it guarantees that some amount of bytes can be read from the underlying stream without blocking.
      Specified by:
      isReady in interface ByteCursor
      Returns:
      true if some data can be read without blocking
      Throws:
      IOException
    • ready

      public int ready() throws IOException
      Provides the number of bytes that can be read from the stream without blocking. This is typically the number of buffered or available bytes within the stream. When this reaches zero then the cursor may perform a blocking read.
      Specified by:
      ready in interface ByteCursor
      Returns:
      the number of bytes that can be read without blocking
      Throws:
      IOException
    • read

      public int read(byte[] data) throws IOException
      Reads a block of bytes from the underlying stream. This will read up to the requested number of bytes from the underlying stream. If there are no ready bytes on the stream this can return zero, representing the fact that nothing was read.
      Specified by:
      read in interface ByteCursor
      Parameters:
      data - this is the array to read the bytes in to
      Returns:
      this returns the number of bytes read from the stream
      Throws:
      IOException
    • read

      public int read(byte[] data, int off, int len) throws IOException
      Reads a block of bytes from the underlying stream. This will read up to the requested number of bytes from the underlying stream. If there are no ready bytes on the stream this can return zero, representing the fact that nothing was read.
      Specified by:
      read in interface ByteCursor
      Parameters:
      data - this is the array to read the bytes in to
      off - this is the offset to begin writing the bytes to
      len - this is the number of bytes that are requested
      Returns:
      this returns the number of bytes read from the stream
      Throws:
      IOException
    • push

      public void push(byte[] data) throws IOException
      Pushes the provided data on to the cursor. Data pushed on to the cursor will be the next data read from the cursor. This complements the reset method which will reset the cursors position on a stream. Allowing data to be pushed on to the cursor allows more flexibility.
      Specified by:
      push in interface ByteCursor
      Parameters:
      data - this is the data to be pushed on to the cursor
      Throws:
      IOException
    • push

      public void push(byte[] data, int off, int len) throws IOException
      Pushes the provided data on to the cursor. Data pushed on to the cursor will be the next data read from the cursor. This complements the reset method which will reset the cursors position on a stream. Allowing data to be pushed on to the cursor allows more flexibility.
      Specified by:
      push in interface ByteCursor
      Parameters:
      data - this is the data to be pushed on to the cursor
      off - this is the offset to begin reading the bytes
      len - this is the number of bytes that are to be used
      Throws:
      IOException
    • expand

      private void expand(int capacity) throws IOException
      This is used to ensure that there is enough space in the buffer to allow for more bytes to be added. If the buffer is already larger than the required capacity the this will do nothing.
      Parameters:
      capacity - the minimum size needed for the buffer
      Throws:
      IOException
    • reset

      public int reset(int size) throws IOException
      Moves the cursor backward within the stream. This ensures that any bytes read from the last read can be pushed back in to the stream so that they can be read again. This will throw an exception if the reset can not be performed.
      Specified by:
      reset in interface ByteCursor
      Parameters:
      size - this is the number of bytes to reset back
      Returns:
      this is the number of bytes that have been reset
      Throws:
      IOException