uk.ac.starlink.fits

Class InputFactory

java.lang.Object

uk.ac.starlink.fits.InputFactory

All Implemented Interfaces:

Closeable, AutoCloseable

public abstract class InputFactory
extends Object
implements Closeable

Represents a sequence of bytes, and can create BasicInput objects to read it.

Since:

2 Dec 2014

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
InputFactory()

Method Summary

Modifier and Type	Method and Description
static InputFactory	createByteStoreFactory(ByteStore byteStore) Returns an input factory based on a populated bytestore.
static InputFactory	createFactory(DataSource datsrc, long offset, long leng) Constructs an instance of this class to read a given data source.
static InputFactory	createFileFactory(File uncompressedFile, long offset, long leng) Constructs an instance of this class to read a given uncompressed file.
abstract BasicInput	createInput(boolean isSeq) Returns a BasicInput instance to read this object's byte stream.
static InputFactory	createRandomFactory(DataSource datsrc, long offset, long leng, StoragePolicy policy) Returns an InputFactory for which random access is guaranteed.
static InputFactory	createSequentialFactory(DataSource datsrc, long offset, long leng) Constructs an instance of this class to read a given data source viewed as a stream, not a file.
static BasicInput	createSequentialInput(InputStream in) Returns a non-random-access BasicInput based on a supplied input stream.
abstract boolean	isRandom() Indicates whether the BasicInput objects created by this factory will support random access.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.io.Closeable

close

Constructor Detail

InputFactory

public InputFactory()

Method Detail

isRandom

public abstract boolean isRandom()

Indicates whether the BasicInput objects created by this factory will support random access.

Returns:

true iff BasicInput.isRandom() will return true for created objects

createInput

public abstract BasicInput createInput(boolean isSeq)
                                throws IOException

Returns a BasicInput instance to read this object's byte stream.

Parameters:

isSeq - if true, the returned object is expected to be used for sequential access only; this value is a hint which may or may not be used by the implementation

Returns:

new reader; if isSeq is false and isRandom returns true, it will be capable of random access

Throws:

IOException

createFactory

public static InputFactory createFactory(DataSource datsrc,
                                         long offset,
                                         long leng)
                                  throws IOException

Constructs an instance of this class to read a given data source.

Parameters:

datsrc - data source

offset - offset into file of stream start

leng - number of bytes in stream

Returns:

new instance

Throws:

IOException

createSequentialFactory

public static InputFactory createSequentialFactory(DataSource datsrc,
                                                   long offset,
                                                   long leng)

Constructs an instance of this class to read a given data source viewed as a stream, not a file.

Parameters:

datsrc - data source

offset - offset into file of stream start

leng - number of bytes in stream

Returns:

new instance

createFileFactory

public static InputFactory createFileFactory(File uncompressedFile,
                                             long offset,
                                             long leng)
                                      throws IOException

Constructs an instance of this class to read a given uncompressed file. It must be uncompressed for the random access to be able to locate the right part to read.

Parameters:

uncompressedFile - unencoded file

offset - offset into file of stream start

leng - number of bytes in stream

Returns:

new instance

Throws:

IOException

createRandomFactory

public static InputFactory createRandomFactory(DataSource datsrc,
                                               long offset,
                                               long leng,
                                               StoragePolicy policy)
                                        throws IOException

Returns an InputFactory for which random access is guaranteed. If necessary, the bytes from the data source will be cached using the supplied storage policy.

Parameters:

datsrc - data source

offset - offset into file of stream start

leng - number of bytes in stream

policy - storage policy for caching if required, or null for default

Returns:

new instance

Throws:

IOException

createByteStoreFactory

public static InputFactory createByteStoreFactory(ByteStore byteStore)
                                           throws IOException

Returns an input factory based on a populated bytestore.

Parameters:

byteStore - cache containing byte content

Returns:

new input factory

Throws:

IOException

createSequentialInput

public static BasicInput createSequentialInput(InputStream in)

Returns a non-random-access BasicInput based on a supplied input stream.

Parameters:

in - input stream

Returns:

non-random BasicInput