Class FileBuffer.Segment

  • All Implemented Interfaces:
    Buffer
    Enclosing class:
    FileBuffer

    private class FileBuffer.Segment
    extends java.lang.Object
    implements Buffer
    The Segment object is used to create a segment of the parent buffer. The segment will write to the parent however if can be read as a unique range of bytes starting with the first sequence of bytes appended to the segment. A segment can be used to create a collection of buffers backed by the same underlying file, as is require with multipart uploads.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private boolean closed
      This determines if the segment is currently open or closed.
      private long first
      This is the offset of the first byte within the sequence.
      private long last
      This is the last byte within the segment for this segment.
      private Buffer parent
      This is the parent buffer that bytes are to be appended to.
      private FileBuffer.Segment segment
      This is an internal segment created from this buffer object.
    • Constructor Summary

      Constructors 
      Constructor Description
      Segment​(Buffer parent, long first)
      Constructor for the Segment object.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Buffer allocate()
      This is used to allocate a segment within this buffer.
      Buffer append​(byte[] array)
      This is used to append the specified data to the underlying file.
      Buffer append​(byte[] array, int off, int size)
      This is used to append the specified data to the underlying file.
      void clear()
      This will clear all data from the buffer.
      void close()
      This method is used to ensure the buffer can be closed.
      java.lang.String encode()
      This method is used to acquire the buffered bytes as a string.
      java.lang.String encode​(java.lang.String charset)
      This method is used to acquire the buffered bytes as a string.
      long length()
      This is used to provide the number of bytes that have been written to the buffer.
      java.io.InputStream open()
      This method is used so that a buffer can be represented as a stream of bytes.
      long space()
      This determines how much space is left in the buffer.
      • Methods inherited from class java.lang.Object

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

      • segment

        private FileBuffer.Segment segment
        This is an internal segment created from this buffer object.
      • parent

        private Buffer parent
        This is the parent buffer that bytes are to be appended to.
      • first

        private long first
        This is the offset of the first byte within the sequence.
      • last

        private long last
        This is the last byte within the segment for this segment.
      • closed

        private boolean closed
        This determines if the segment is currently open or closed.
    • Constructor Detail

      • Segment

        public Segment​(Buffer parent,
                       long first)
        Constructor for the Segment object. This is used to create a segment from a parent buffer. A segment is a part of the parent buffer and appends its bytes to the parent. It can however be treated as an independent source of bytes.
        Parameters:
        parent - this is the parent buffer to be appended to
        first - this is the offset for the first byte in this
    • Method Detail

      • allocate

        public Buffer allocate()
                        throws java.io.IOException
        This is used to allocate a segment within this buffer. If the buffer is closed this will throw an exception, if however the buffer is still open then a segment is created which will write all appended data to this buffer. However it can be treated as an independent source of data.
        Specified by:
        allocate in interface Buffer
        Returns:
        this returns a buffer which is a segment of this
        Throws:
        java.io.IOException
      • append

        public Buffer append​(byte[] array)
                      throws java.io.IOException
        This is used to append the specified data to the underlying file. All bytes appended to the file can be consumed at a later stage by acquiring the InputStream from this buffer. Also if require the data can be encoded as a string object in a required character set.
        Specified by:
        append in interface Buffer
        Parameters:
        array - this is the array to write the the file
        Returns:
        this returns this buffer for further operations
        Throws:
        java.io.IOException
      • append

        public Buffer append​(byte[] array,
                             int off,
                             int size)
                      throws java.io.IOException
        This is used to append the specified data to the underlying file. All bytes appended to the file can be consumed at a later stage by acquiring the InputStream from this buffer. Also if require the data can be encoded as a string object in a required character set.
        Specified by:
        append in interface Buffer
        Parameters:
        array - this is the array to write the the file
        off - this is the offset within the array to write
        size - this is the number of bytes to be appended
        Returns:
        this returns this buffer for further operations
        Throws:
        java.io.IOException
      • encode

        public java.lang.String encode()
                                throws java.io.IOException
        This method is used to acquire the buffered bytes as a string. This is useful if the contents need to be manipulated as a string or transferred into another encoding. If the UTF-8 content encoding is not supported the platform default is used, however this is unlikely as UTF-8 should be supported.
        Specified by:
        encode in interface Buffer
        Returns:
        this returns a UTF-8 encoding of the buffer contents
        Throws:
        java.io.IOException
      • encode

        public java.lang.String encode​(java.lang.String charset)
                                throws java.io.IOException
        This method is used to acquire the buffered bytes as a string. This is useful if the contents need to be manipulated as a string or transferred into another encoding. This will convert the bytes using the specified character encoding format.
        Specified by:
        encode in interface Buffer
        Parameters:
        charset - this is the charset to encode the data with
        Returns:
        this returns the encoding of the buffer contents
        Throws:
        java.io.IOException
      • open

        public java.io.InputStream open()
                                 throws java.io.IOException
        This method is used so that a buffer can be represented as a stream of bytes. This provides a quick means to access the data that has been written to the buffer. It wraps the buffer within an input stream so that it can be read directly.
        Specified by:
        open in interface Buffer
        Returns:
        a stream that can be used to read the buffered bytes
        Throws:
        java.io.IOException
      • clear

        public void clear()
                   throws java.io.IOException
        This will clear all data from the buffer. This simply sets the count to be zero, it will not clear the memory occupied by the instance as the internal buffer will remain. This allows the memory occupied to be reused as many times as is required.
        Specified by:
        clear in interface Buffer
        Throws:
        java.io.IOException
      • close

        public void close()
                   throws java.io.IOException
        This method is used to ensure the buffer can be closed. Once the buffer is closed it is an immutable collection of bytes and can not longer be modified. This ensures that it can be passed by value without the risk of modification of the bytes.
        Specified by:
        close in interface Buffer
        Throws:
        java.io.IOException
      • space

        public long space()
        This determines how much space is left in the buffer. If there is no limit to the buffer size this will return the maximum long value. Typically this is the capacity minus the length.
        Returns:
        this is the space that is available within the buffer
      • length

        public long length()
        This is used to provide the number of bytes that have been written to the buffer. This increases as bytes are appended to the buffer. if the buffer is cleared this resets to zero.
        Specified by:
        length in interface Buffer
        Returns:
        this returns the number of bytes within the buffer