Package com.itextpdf.text.io

Class MappedChannelRandomAccessSource

java.lang.Object
com.itextpdf.text.io.MappedChannelRandomAccessSource
All Implemented Interfaces:
RandomAccessSource
class MappedChannelRandomAccessSource extends Object implements RandomAccessSource
A RandomAccessSource that represents a memory mapped section of an underlying FileChannel. This source can be closed and will automatically re-open as needed. This class is an internal implementation detail of the FileChannelRandomAccessSource class and shouldn't be used by general iText users.
Since:
5.3.5

  • Field Details

    • channel

      private final FileChannel channel
      The underlying channel

    • offset

      private final long offset
      The offset into the channel that this source maps to

    • length

      private final long length
      The number of bytes this source maps to

    • source

      private ByteBufferRandomAccessSource source
      If the map is active, the actual map. null other wise.

  • Constructor Details

    • MappedChannelRandomAccessSource

      public MappedChannelRandomAccessSource(FileChannel channel, long offset, long length)
      Create a new source based on the channel. Mapping will not occur until data is actually read.
      Parameters:
      channel - the underlying channel
      offset - the offset of the map
      length - the length of the map

  • Method Details

    • open

      void open() throws IOException
      Map the region of the channel
      Throws:
      IOException - if there is a problem with creating the map

    • exceptionIsMapFailureException

      private static boolean exceptionIsMapFailureException(IOException e)
      Utility method that determines whether a given IOException is the result of a failure to map a memory mapped file. It would be better if the runtime provided a special exception for this case, but it doesn't, so we have to rely on parsing the exception message.
      Parameters:
      e - the exception to check
      Returns:
      true if the exception was the result of a failure to map a memory mapped file

    • get

      public int get(long position) throws IOException
      Gets a byte at the specified position
      Specified by:
      get in interface RandomAccessSource
      Parameters:
      position -
      Returns:
      the byte, or -1 if EOF is reached
      Throws:
      IOException

    • get

      public int get(long position, byte[] bytes, int off, int len) throws IOException
      Gets an array at the specified position. If the number of bytes requested cannot be read, the bytes that can be read will be placed in bytes and the number actually read will be returned.
      Specified by:
      get in interface RandomAccessSource
      Parameters:
      position - the position in the RandomAccessSource to read from
      bytes - output buffer
      off - offset into the output buffer where results will be placed
      len - the number of bytes to read
      Returns:
      the number of bytes actually read, or -1 if the file is at EOF
      Throws:
      IOException

    • length

      public long length()
      Specified by:
      length in interface RandomAccessSource
      Returns:
      the length of this source

    • close

      public void close() throws IOException
      Closes this source. The underlying data structure or source (if any) will also be closed
      Specified by:
      close in interface RandomAccessSource
      Throws:
      IOException

    • toString

      public String toString()
      Overrides:
      toString in class Object