Package de.intarsys.tools.randomaccess

Class RandomAccessViewport

java.lang.Object
de.intarsys.tools.randomaccess.AbstractRandomAccess
de.intarsys.tools.randomaccess.RandomAccessFilter
de.intarsys.tools.randomaccess.RandomAccessViewport
All Implemented Interfaces:
IRandomAccess
public class RandomAccessViewport extends RandomAccessFilter
A viewport in an existing IRandomAccess.

  • Field Summary

    Fields inherited from class de.intarsys.tools.randomaccess.RandomAccessFilter

    random

  • Constructor Summary

    Constructors
    Constructor
    Description
    RandomAccessViewport(IRandomAccess ra, long offset, long length)
    Create a viewport to the existing IRandomAccess ra.

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    getLength()
    Returns the length of this data container.
    long
    getOffset()
    Returns the current offset in this data container.
    protected long
    getViewEnd()
     
    protected long
    getViewLength()
     
    protected long
    getViewOffset()
     
    boolean
    isReadOnly()
    true if this is a read only data container.
    int
    read()
    Reads a byte of data from this data container.
    int
    read(byte[] buffer)
    Reads up to buffer.length bytes of data from this data container into an array of bytes.
    int
    read(byte[] buffer, int start, int numBytes)
    Reads up to len bytes of data from this data container into an array of bytes.
    void
    seek(long offset)
    Sets the offset, measured from the beginning of the data container at which the next read or write occurs.
    void
    seekBy(long delta)
    Sets the offset, measured from the current offset at which the next read or write occurs.
    void
    setLength(long newLength)
    Assign the length.
    void
    write(byte[] buffer)
    Writes b.length bytes from the specified byte array, starting at the current offset.
    void
    write(byte[] buffer, int start, int numBytes)
    Writes len bytes from the specified byte array starting at start.
    void
    write(int b)
    Writes the specified byte .

    Methods inherited from class de.intarsys.tools.randomaccess.RandomAccessFilter

    close, flush, getRandom

    Methods inherited from class de.intarsys.tools.randomaccess.AbstractRandomAccess

    asInputStream, asOutputStream, getPositionStack, mark, reset

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • RandomAccessViewport

      public RandomAccessViewport(IRandomAccess ra, long offset, long length) throws IOException
      Create a viewport to the existing IRandomAccess ra.

      ATTENTION: This will not seek to offset in ra. This means after creation before initial use you have to position the IRandomAccess yourself using seek.

      Parameters:
      ra -
      offset -
      length -
      Throws:
      IOException

  • Method Details

    • getLength

      public long getLength() throws IOException
      Description copied from interface: IRandomAccess
      Returns the length of this data container.
      Specified by:
      getLength in interface IRandomAccess
      Overrides:
      getLength in class RandomAccessFilter
      Returns:
      the length of this data container, measured in bytes.
      Throws:
      IOException - if an I/O error occurs.

    • getOffset

      public long getOffset() throws IOException
      Description copied from interface: IRandomAccess
      Returns the current offset in this data container.
      Specified by:
      getOffset in interface IRandomAccess
      Overrides:
      getOffset in class RandomAccessFilter
      Returns:
      the offset from the beginning of the data container, in bytes, at which the next read or write occurs.
      Throws:
      IOException - if an I/O error occurs.

    • getViewEnd

      protected long getViewEnd()

    • getViewLength

      protected long getViewLength()

    • getViewOffset

      protected long getViewOffset()

    • isReadOnly

      public boolean isReadOnly()
      Description copied from interface: IRandomAccess
      true if this is a read only data container.
      Specified by:
      isReadOnly in interface IRandomAccess
      Overrides:
      isReadOnly in class RandomAccessFilter
      Returns:
      true if this is a read only data container.

    • read

      public int read() throws IOException
      Description copied from interface: IRandomAccess
      Reads a byte of data from this data container. The byte is returned as an integer in the range 0 to 255 (0x00-0x0ff). This method blocks if no input is yet available.

      This method behaves in exactly the same way as the InputStream.read() method of InputStream.

      Specified by:
      read in interface IRandomAccess
      Overrides:
      read in class RandomAccessFilter
      Returns:
      the next byte of data, or -1 if the end of the data container has been reached.
      Throws:
      IOException - if an I/O error occurs. Not thrown if the end of the data container has been reached.

    • read

      public int read(byte[] buffer) throws IOException
      Description copied from interface: IRandomAccess
      Reads up to buffer.length bytes of data from this data container into an array of bytes. This method blocks until at least one byte of input is available.

      This method behaves in the exactly the same way as the InputStream.read(byte[]) method of InputStream.

      Specified by:
      read in interface IRandomAccess
      Overrides:
      read in class RandomAccessFilter
      Parameters:
      buffer - the buffer into which the data is read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of this data container has been reached.
      Throws:
      IOException - if an I/O error occurs.

    • read

      public int read(byte[] buffer, int start, int numBytes) throws IOException
      Description copied from interface: IRandomAccess
      Reads up to len bytes of data from this data container into an array of bytes. This method blocks until at least one byte of input is available.

      Specified by:
      read in interface IRandomAccess
      Overrides:
      read in class RandomAccessFilter
      Parameters:
      buffer - the buffer into which the data is read.
      start - the start offset of the data.
      numBytes - the maximum number of bytes read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
      Throws:
      IOException - if an I/O error occurs.

    • seek

      public void seek(long offset) throws IOException
      Description copied from interface: IRandomAccess
      Sets the offset, measured from the beginning of the data container at which the next read or write occurs. The offset may be set beyond the end of the data container. Setting the offset beyond the end of the data container does not change the data container length. The length will change only by writing after the offset has been set beyond the end of the data container.
      Specified by:
      seek in interface IRandomAccess
      Overrides:
      seek in class RandomAccessFilter
      Parameters:
      offset - the offset position, measured in bytes from the beginning of the data container
      Throws:
      IOException - if offset is less than 0 or if an I/O error occurs.

    • seekBy

      public void seekBy(long delta) throws IOException
      Description copied from interface: IRandomAccess
      Sets the offset, measured from the current offset at which the next read or write occurs. The offset may be set beyond the end of the data container. Setting the offset beyond the end of the data container does not change the data container length. The length will change only by writing after the offset has been set beyond the end of the data container.
      Specified by:
      seekBy in interface IRandomAccess
      Overrides:
      seekBy in class RandomAccessFilter
      Parameters:
      delta - the amount of bytes by which to change the current offset position
      Throws:
      IOException - if the resulting offset is less than 0 or if an I/O error occurs.

    • setLength

      public void setLength(long newLength) throws IOException
      Description copied from interface: IRandomAccess
      Assign the length. All bytes after length are truncated. If the real length is currently less than newLength, the data structure will be enlarged.
      Specified by:
      setLength in interface IRandomAccess
      Overrides:
      setLength in class RandomAccessFilter
      Parameters:
      newLength -
      Throws:
      IOException

    • write

      public void write(byte[] buffer) throws IOException
      Description copied from interface: IRandomAccess
      Writes b.length bytes from the specified byte array, starting at the current offset.
      Specified by:
      write in interface IRandomAccess
      Overrides:
      write in class RandomAccessFilter
      Parameters:
      buffer - the data.
      Throws:
      IOException - if an I/O error occurs.

    • write

      public void write(byte[] buffer, int start, int numBytes) throws IOException
      Description copied from interface: IRandomAccess
      Writes len bytes from the specified byte array starting at start.
      Specified by:
      write in interface IRandomAccess
      Overrides:
      write in class RandomAccessFilter
      Parameters:
      buffer - the data.
      start - the start offset in the data.
      numBytes - the number of bytes to write.
      Throws:
      IOException - if an I/O error occurs.

    • write

      public void write(int b) throws IOException
      Description copied from interface: IRandomAccess
      Writes the specified byte . The write starts at the current offset.
      Specified by:
      write in interface IRandomAccess
      Overrides:
      write in class RandomAccessFilter
      Parameters:
      b - the byte to be written.
      Throws:
      IOException - if an I/O error occurs.