Package uk.ac.starlink.array

Class CombineArrayImpl

  • All Implemented Interfaces:
    ArrayImpl
    public class CombineArrayImpl
extends java.lang.Object
implements ArrayImpl
    Virtual NDArray implementation combining two given NDArrays using an arbitrary arithmetic function. Each pixel in the resulting array is the result of combining the two corresponding pixels of the input arrays using a supplied Combiner object. Type conversions are taken care of, and values which end up outside the range of the type of the resulting array are automatically turned Bad.
    Author:
    Mark Taylor (Starlink)

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean canMap()
      Indicates whether mapped access is available.
      void close()
      Shuts down this ArrayImpl for pixel access.
      AccessImpl getAccess()
      Returns an object which can access the pixels of this ArrayImpl.
      java.lang.Number getBadValue()
      The magic bad value for data.
      java.lang.Object getMapped()
      Returns a single primitive array holding all the pixel data of this array.
      OrderedNDShape getShape()
      Returns an object representing the shape (origin and dimensions) and pixel sequence of this object.
      Type getType()
      Returns the primitive type of the data held by this object.
      boolean isRandom()
      Indicates whether random access is possible.
      boolean isReadable()
      Indicates whether read access is possible.
      boolean isWritable()
      Indicates whether write access is possible.
      boolean multipleAccess()
      Indicates whether the getAccess method may be called more than once.
      void open()
      Prepares this ArrayImpl for pixel access.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • CombineArrayImpl

        public CombineArrayImpl​(NDArray nda1,
                        NDArray nda2,
                        Combiner combi,
                        NDShape shape,
                        Type type,
                        BadHandler bh)
        Construct a new CombineArrayImpl based on two underlying NDArrays and a combiner object. The supplied array objects do not need to be the same type or shape or the same type or shape as the resulting array object. Values outside the shape of one or the other will be presented as a Bad value to the Combiner object.
        Parameters:
        nda1 - the first array to combine
        nda2 - the second array to combine
        combi - the object which performs the arithmetic combination
        shape - the shape of the resulting array object
        type - the type of the resulting array object
        bh - the bad value handler for the resulting array object. If null, a non-null bad value handler using a default value is used.

    • 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
        Returns:
        the ordered shape

      • getType

        public Type getType()
        Description copied from interface: ArrayImpl
        Returns the primitive type of the data held by this object. The return value must not change over the lifetime of the object.
        Specified by:
        getType in interface ArrayImpl
        Returns:
        an object representing the type of data held.

      • getBadValue

        public java.lang.Number getBadValue()
        Description copied from interface: ArrayImpl
        The magic bad value for data. The returned type should be one of the primitive wrapper types, Byte, Short, Integer, Float, Double as appropriate for the type of this array. It may be null if there is no bad value. The return value must not change over the lifetime of the object.
        Specified by:
        getBadValue in interface ArrayImpl
        Returns:
        the bad value

      • isReadable

        public boolean isReadable()
        Description copied from interface: ArrayImpl
        Indicates whether read access is possible. Reads will only be attempted if this method returns true. The return value must not change over the lifetime of the object.
        Specified by:
        isReadable in interface ArrayImpl
        Returns:
        whether read access is available

      • isWritable

        public boolean isWritable()
        Description copied from interface: ArrayImpl
        Indicates whether write access is possible. Writes will only be attempted if this method returns true. The return value must not change over the lifetime of the object.
        Specified by:
        isWritable in interface ArrayImpl
        Returns:
        whether write access is available

      • isRandom

        public boolean isRandom()
        Description copied from interface: ArrayImpl
        Indicates whether random access is possible. If this method returns true, then it is permissible to set the offset to a value lower than its current value. If it is false, then no such invocations will be attempted. The return value must not change over the lifetime of the object.
        Specified by:
        isRandom in interface ArrayImpl
        Returns:
        whether random access is available

      • multipleAccess

        public boolean multipleAccess()
        Description copied from interface: ArrayImpl
        Indicates whether the getAccess method may be called more than once.
        Specified by:
        multipleAccess in interface ArrayImpl
        Returns:
        true if getAccess may be called more than once

      • open

        public void open()
          throws java.io.IOException
        Description copied from interface: ArrayImpl
        Prepares this ArrayImpl for pixel access. This method will be called no more than once, and it will be called prior to any calls of the getAccess method.
        Specified by:
        open in interface ArrayImpl
        Throws:
        java.io.IOException - if there is an IO error

      • canMap

        public boolean canMap()
        Description copied from interface: ArrayImpl
        Indicates whether mapped access is available. If true, then following an open call, the getMapped method will return a reference to the java primitive array containing all the pixels of this array.

        Will only be called after an open call, and before any close call.

        Specified by:
        canMap in interface ArrayImpl

      • getMapped

        public java.lang.Object getMapped()
        Description copied from interface: ArrayImpl
        Returns a single primitive array holding all the pixel data of this array. This should be a cheap operation, returning a reference to an existing array rather than doing work to generate one. In the case of a writable accessor, making changes to the returned primitive array will result in changes to the accessor pixel data. In the case of an NDArray which is not writable, the effect of making changes to the returned array is undefined; in particular it may result in an exception.

        Will only be called if canMap returns true, and only after an open call and before any close call.

        Specified by:
        getMapped in interface ArrayImpl

      • getAccess

        public AccessImpl getAccess()
                     throws java.io.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
        Returns:
        an accessor for the pixel data
        Throws:
        java.io.IOException - if there is an IO error

      • close

        public void close()
           throws java.io.IOException
        Description copied from interface: ArrayImpl
        Shuts down this ArrayImpl for pixel access. This method will be called no more than once. No calls to getAccess, getMapped or open will be made after it is called. If the user makes proper use of the NDArray classes, it will be called after any AccessImpl objects and references to the mapped array are no longer required. If the user misbehaves however it may not get called at all, so an effort should be made to realease non-memory resources and flush buffers where appropriate in the finalizer.
        Specified by:
        close in interface ArrayImpl
        Throws:
        java.io.IOException - if there is an IO error