uk.ac.starlink.array
Class WindowArrayImpl

java.lang.Object
  extended by uk.ac.starlink.array.WrapperArrayImpl
      extended by uk.ac.starlink.array.WindowArrayImpl
All Implemented Interfaces:
ArrayImpl

public class WindowArrayImpl
extends WrapperArrayImpl

Wraps an NDArray to produce a virtual ArrayImpl with a different shape. The result is a 'window' on the base array; a given position (coordinate vector) refers to the same pixel in both base and wrapping array, but pixels outside the window will not exist in the wrapping array and pixels in the window which do not fall within the bounds of the base array are given the bad value (for a readable array) or ignored (for a writable array).

The window may fall wholly or partially within or without the bounds of the base array, but must be of the same dimensionality as it.

Author:
Mark Taylor (Starlink)

Constructor Summary
WindowArrayImpl(NDArray nda, NDShape window)
          Constructs a new ArrayImpl from a base NDArray and a given window shape.
 
Method Summary
 AccessImpl getAccess()
          Returns an object which can access the pixels of this ArrayImpl.
 BadHandler getBadHandler()
           
 OrderedNDShape getShape()
          Returns an object representing the shape (origin and dimensions) and pixel sequence of this object.
 
Methods inherited from class uk.ac.starlink.array.WrapperArrayImpl
canMap, close, getBadValue, getMapped, getType, getWrapped, isRandom, isReadable, isWritable, multipleAccess, open, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

WindowArrayImpl

public WindowArrayImpl(NDArray nda,
                       NDShape window)
Constructs a new ArrayImpl from a base NDArray and a given window shape.

Parameters:
nda - the base NDArray which supplies the original pixel values
window - the shape of the window through which the base array will be viewed. Must have the same number of dimensions as nda
Throws:
IllegalArgumentException - if window has a different number of dimensions from nda
Method Detail

getShape

public OrderedNDShape getShape()
Description copied from interface: ArrayImpl
Returns an object representing the shape (origin and dimensions) and pixel sequence of this object. The return value must not change over the lifetime of the object.

Specified by:
getShape in interface ArrayImpl
Overrides:
getShape in class WrapperArrayImpl
Returns:
the ordered shape

getBadHandler

public BadHandler getBadHandler()

getAccess

public AccessImpl getAccess()
                     throws IOException
Description copied from interface: ArrayImpl
Returns an object which can access the pixels of this ArrayImpl. Each call to this method returns a new and independent AccessImpl, with an offset initialised to 0 (the start of the array data).

This method will only be called after the sole call to open and before the sole call to close.

This method will only be called more than once if the multipleAccess method returns true.

It is the responsibility of the caller to close the returned AccessImpl when it is no longer required; this enables resources it may hold to be released.

Specified by:
getAccess in interface ArrayImpl
Overrides:
getAccess in class WrapperArrayImpl
Returns:
an accessor for the pixel data
Throws:
IOException - if there is an IO error


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