Package nom.tam.fits

Class FitsHeap

  • All Implemented Interfaces:
    FitsElement
    public class FitsHeap
extends java.lang.Object
implements FitsElement
    This class supports the FITS heap. This is currently used for variable length columns in binary tables.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private BufferedDataInputStream bstr
      A stream used to read the heap data
      private byte[] heap
      The storage buffer
      private int heapOffset
      Our current offset into the heap.
      private int heapSize
      The current used size of the buffer <= heap.length
      private static int MINIMUM_HEAP_SIZE  

    • Constructor Summary

      Constructors 
      Constructor Description
      FitsHeap​(int size)
      Create a heap of a given size.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private void allocate()  
      (package private) FitsHeap copy()
      Add a copy constructor to allow us to duplicate a heap.
      (package private) void expandHeap​(int need)
      Check if the Heap can accommodate a given requirement.
      void getData​(int offset, java.lang.Object array)
      Get data from the heap.
      long getFileOffset()
      Get the file offset of the heap
      long getSize()
      Return the size of the heap using the more bean compatible format
      (package private) int putData​(java.lang.Object data)
      Add some data to the heap.
      void read​(ArrayDataInput str)
      Read the heap
      boolean reset()
      Reset the input stream to point to the beginning of this element
      void rewrite()
      Rewrite the contents of the element in place.
      boolean rewriteable()  
      int size()  
      void write​(ArrayDataOutput str)
      Write the heap

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • heap

        private byte[] heap
        The storage buffer

      • heapSize

        private int heapSize
        The current used size of the buffer <= heap.length

      • heapOffset

        private int heapOffset
        Our current offset into the heap. When we read from the heap we use a byte array input stream. So long as we continue to read further into the heap, we can continue to use the same stream, but we need to recreate the stream whenever we skip backwards.

    • Constructor Detail

      • FitsHeap

        FitsHeap​(int size)
        Create a heap of a given size.

    • Method Detail

      • allocate

        private void allocate()

      • copy

        FitsHeap copy()
        Add a copy constructor to allow us to duplicate a heap. This would be necessary if we wanted to copy an HDU that included variable length columns.

      • expandHeap

        void expandHeap​(int need)
        Check if the Heap can accommodate a given requirement. If not expand the heap.

      • getData

        public void getData​(int offset,
                    java.lang.Object array)
             throws FitsException
        Get data from the heap.
        Parameters:
        offset - The offset at which the data begins.
        array - The array to be extracted.
        Throws:
        FitsException - if the operation failed

      • getFileOffset

        public long getFileOffset()
        Get the file offset of the heap
        Specified by:
        getFileOffset in interface FitsElement
        Returns:
        the byte at which this element begins. This is only available if the data is originally read from a random access medium.

      • getSize

        public long getSize()
        Return the size of the heap using the more bean compatible format
        Specified by:
        getSize in interface FitsElement
        Returns:
        The size of this element in bytes

      • reset

        public boolean reset()
        Description copied from interface: FitsElement
        Reset the input stream to point to the beginning of this element
        Specified by:
        reset in interface FitsElement
        Returns:
        True if the reset succeeded.

      • rewrite

        public void rewrite()
             throws java.io.IOException,
                    FitsException
        Description copied from interface: FitsElement
        Rewrite the contents of the element in place. The data must have been originally read from a random access device, and the size of the element may not have changed.
        Specified by:
        rewrite in interface FitsElement
        Throws:
        java.io.IOException - if the rewrite was unsuccessful.
        FitsException - if the rewrite was unsuccessful.

      • rewriteable

        public boolean rewriteable()
        Specified by:
        rewriteable in interface FitsElement
        Returns:
        true if this element can be rewritten?

      • size

        public int size()
        Returns:
        the size of the Heap