public double getSize () {
    // your code goes here
  }
  
  public int seek (double off) {
    double boff = ...; // <-- your code goes here
    
    // The code below this line comes from BaseFile
    offset = boff;
    if (io!=null) io.seek((long)boff);
    return 0; // <-- always returns 0
  }

  public double seek() {
    // your code goes here
  }

  public double avail() {
    // your code goes here
  }

• This returns the size of the file in number of elements.
• The getLength() method in I/O Resource will tell us the total size of the file in bytes.
• From this we need to subtract the size of the header (HEADER_SIZE) and then convert from bytes to elements.
• Here we use the constant BPE which is the number of bytes-per-element for our data. In an ORANGE file all data is either SL or SF data which is always 4 bytes-per-element. If we had a more complicated file, we would probably have a variable or method that held the current number of bytes-per-element.

• The seek methods move the read/write pointer within the data portion of the file.
• I/O resource provides methods to set/get the seek value (seek() and seek(long)) however (like getLength()) they are measured in bytes and include the size of the header.

• The avail method tells us how many elemets are available (starting at the current read/write pointer) before the end of the file.
• Here, if we use the seek() and getSize() we just wrote, we end up with a simple subtraction problem.

• Now now when you status the file you will see the correct size.

  nM> status samplefile.orange
  OrangeFile  :  file:///home/student/samplefile.orange
  Size        :  16
  Format      :  SF
  XStart      :  0.0
  XDelta      :  1.0
  

• After building the class, we need to add an entry to the file handlers table that will tell NeXtMidas to use your new file handler when it sees an ORANGE file:

  nM> set REG.HANDLERS.FILE.ORANGE "nxm.train.lib.OrangeFile"

• Save the sample file samplefile.orange to your local disk and try it out.

  nM> status samplefile.orange

• After completing Part 2, your class will look similar to this.