Package org.apache.pdfbox.io

Class NonSeekableRandomAccessReadInputStream

java.lang.Object
org.apache.pdfbox.io.NonSeekableRandomAccessReadInputStream
All Implemented Interfaces:
Closeable, AutoCloseable, RandomAccessRead
public class NonSeekableRandomAccessReadInputStream extends Object implements RandomAccessRead
An implementation of the RandomAccessRead interface using an InputStream as source. It is optimized for a minimal memory footprint by using a small buffer to read from the input stream instead of copying the whole input stream to memory. This reduces the random access read abilities, so that peek/rewind operations are limited to the data within the buffer. This class is meant to be used by consumers which process the data more or less in a serial manner and therefore don't need full random access.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected int
    currentBufferPointer
     
    protected long
    position
     
    protected long
    size
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    NonSeekableRandomAccessReadInputStream(InputStream inputStream)
    Default constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    available()
    Returns an estimate of the number of bytes that can be read (or skipped over) from the underlying input stream without blocking, which may be 0, or 0 when end of stream is detected.
    protected void
    checkClosed()
    Ensure that the RandomAccessBuffer is not closed
    void
    close()
    RandomAccessReadView
    createView(long startPosition, long streamLength)
    Creates a random access read view starting at the given position with the given length.
    long
    getPosition()
    Returns offset of next byte to be returned by a read method.
    boolean
    isClosed()
    Returns true if this source has been closed.
    boolean
    isEOF()
    A simple test to see if we are at the end of the data.
    long
    length()
    The total number of bytes that are available.
    int
    read()
    Read a single byte of data.
    int
    read(byte[] b, int offset, int length)
    Read a buffer of data.
    void
    readFully(byte[] b, int offset, int length)
    Same as RandomAccessRead.read(byte[], int, int) but will loop until exactly length bytes are read or it will throw an exception.
    void
    rewind(int bytes)
    Seek backwards the given number of bytes.
    void
    seek(long position)
    Seek to a position in the data.
    void
    skip(int length)
    Skips a given number of bytes.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface org.apache.pdfbox.io.RandomAccessRead

    peek, read, readFully

  • Field Details

    • position

      protected long position

    • currentBufferPointer

      protected int currentBufferPointer

    • size

      protected long size

  • Constructor Details

    • NonSeekableRandomAccessReadInputStream

      public NonSeekableRandomAccessReadInputStream(InputStream inputStream)
      Default constructor.

  • Method Details

    • close

      public void close() throws IOException
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Throws:
      IOException

    • seek

      public void seek(long position) throws IOException
      Seek to a position in the data.
      Specified by:
      seek in interface RandomAccessRead
      Parameters:
      position - The position to seek to.
      Throws:
      IOException - If there is an error while seeking.

    • skip

      public void skip(int length) throws IOException
      Description copied from interface: RandomAccessRead
      Skips a given number of bytes.
      Specified by:
      skip in interface RandomAccessRead
      Parameters:
      length - the number of bytes to be skipped
      Throws:
      IOException - if an I/O error occurs while reading data

    • getPosition

      public long getPosition() throws IOException
      Returns offset of next byte to be returned by a read method.
      Specified by:
      getPosition in interface RandomAccessRead
      Returns:
      offset of next byte which will be returned with next RandomAccessRead.read() (if no more bytes are left it returns a value >= length of source)
      Throws:
      IOException - If there was an error while getting the current position

    • read

      public int read() throws IOException
      Read a single byte of data.
      Specified by:
      read in interface RandomAccessRead
      Returns:
      The byte of data that is being read.
      Throws:
      IOException - If there is an error while reading the data.

    • read

      public int read(byte[] b, int offset, int length) throws IOException
      Read a buffer of data.
      Specified by:
      read in interface RandomAccessRead
      Parameters:
      b - The buffer to write the data to.
      offset - Offset into the buffer to start writing.
      length - The amount of data to attempt to read.
      Returns:
      The number of bytes that were actually read.
      Throws:
      IOException - If there was an error while reading the data.

    • readFully

      public void readFully(byte[] b, int offset, int length) throws IOException
      Description copied from interface: RandomAccessRead
      Same as RandomAccessRead.read(byte[], int, int) but will loop until exactly length bytes are read or it will throw an exception.
      Specified by:
      readFully in interface RandomAccessRead
      Parameters:
      b - The buffer to write the data to.
      offset - Offset into the buffer to start writing.
      length - The exact amount of data to attempt to read.
      Throws:
      IOException

    • available

      public int available() throws IOException
      Returns an estimate of the number of bytes that can be read (or skipped over) from the underlying input stream without blocking, which may be 0, or 0 when end of stream is detected.
      Specified by:
      available in interface RandomAccessRead
      Returns:
      the number of bytes that can be read
      Throws:
      IOException - if this random access has been closed

    • length

      public long length() throws IOException
      The total number of bytes that are available.
      Specified by:
      length in interface RandomAccessRead
      Returns:
      The number of bytes available.
      Throws:
      IOException - If there is an IO error while determining the length of the data stream.

    • rewind

      public void rewind(int bytes) throws IOException
      Description copied from interface: RandomAccessRead
      Seek backwards the given number of bytes.
      Specified by:
      rewind in interface RandomAccessRead
      Parameters:
      bytes - the number of bytes to be seeked backwards
      Throws:
      IOException - If there is an error while seeking

    • checkClosed

      protected void checkClosed() throws IOException
      Ensure that the RandomAccessBuffer is not closed
      Throws:
      IOException - If RandomAccessBuffer already closed

    • isClosed

      public boolean isClosed()
      Returns true if this source has been closed.
      Specified by:
      isClosed in interface RandomAccessRead
      Returns:
      true if the source has been closed

    • isEOF

      public boolean isEOF() throws IOException
      A simple test to see if we are at the end of the data.
      Specified by:
      isEOF in interface RandomAccessRead
      Returns:
      true if we are at the end of the data.
      Throws:
      IOException - If there is an error reading the next byte.

    • createView

      public RandomAccessReadView createView(long startPosition, long streamLength) throws IOException
      Description copied from interface: RandomAccessRead
      Creates a random access read view starting at the given position with the given length.
      Specified by:
      createView in interface RandomAccessRead
      Parameters:
      startPosition - start position within the underlying random access read
      streamLength - stream length
      Returns:
      the random access read view
      Throws:
      IOException - if something went wrong when creating the view for the RandomAccessRead