NioArrayImpl (Starlink-UK API)

java.lang.Object
- uk.ac.starlink.array.NioArrayImpl

All Implemented Interfaces:

ArrayImpl
```
public class NioArrayImpl
extends Object
implements ArrayImpl
```
Implementation of ArrayImpl which uses a Buffer for the data storage. Can be used in such a way that the buffer itself is not actually created until it is required (and hence is never created if it is not required).

Author:

Mark Taylor (Starlink)

See Also:

Buffer

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static interface NioArrayImpl.BufferGetter
Defines an object which can provide deferred access to a Buffer.

Nested Classes
Modifier and Type	Class and Description
`static interface`	`NioArrayImpl.BufferGetter` Defines an object which can provide deferred access to a `Buffer`.

Constructor Summary

Constructors
Constructor and Description
`NioArrayImpl(Buffer buf, OrderedNDShape oshape, Type type, Number badval)` Constructs an ArrayImpl from a `Buffer`.
`NioArrayImpl(NioArrayImpl.BufferGetter bufget, OrderedNDShape oshape, Type type, Number badval)` Constructs an ArrayImpl using a deferred-access buffer object.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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.
`Number`	`getBadValue()` The magic bad value for data.
`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
  - NioArrayImpl
```
public NioArrayImpl(NioArrayImpl.BufferGetter bufget,
                    OrderedNDShape oshape,
                    Type type,
                    Number badval)
```
    Constructs an ArrayImpl using a deferred-access buffer object. This constructor will only create the NIO buffer when it is required - if pixel access is never performed the buffer is never created.
    
    Parameters:
    
    bufget - an object which can do deferred creation of a Buffer
    
    oshape - the shape of the array
    
    type - the data type of the array
    
    badval - the magic bad value for the array (may be null)
  - NioArrayImpl
```
public NioArrayImpl(Buffer buf,
                    OrderedNDShape oshape,
                    Type type,
                    Number badval)
```
    Constructs an ArrayImpl from a Buffer.
    
    Parameters:
    
    buf - an NIO buffer
    
    oshape - the shape of the array
    
    type - the data type of the array
    
    badval - the magic bad value for the array (may be null)
- Method Detail
  - open
```
public void open()
          throws 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:
    
    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 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
  - close
```
public void close()
           throws 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:
    
    IOException - if there is an IO error
  - 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 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
  - 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
  - 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
  - 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
  - getAccess
```
public AccessImpl getAccess()
```
    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

Class NioArrayImpl

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

NioArrayImpl

NioArrayImpl

Method Detail

open

canMap

getMapped

close

getShape

getType

getBadValue

isRandom

isReadable

isWritable

multipleAccess

getAccess