uk.ac.starlink.datanode.nodes

Class FITSDataNode

java.lang.Object

uk.ac.starlink.datanode.nodes.DefaultDataNode

uk.ac.starlink.datanode.nodes.FITSDataNode

All Implemented Interfaces:

DataNode

Direct Known Subclasses:

FITSFileDataNode, FITSStreamDataNode

public abstract class FITSDataNode
extends DefaultDataNode

Abstract DataNode class for representing FITS objects. Subclasses are provided for FITS objects on disk or in a stream.

Author:

Mark Taylor (Starlink)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FITSDataNode.ArrayDataMaker Interface used for objects which can supply an ArrayDataInput object on demand (more than once if necessary).

Constructor Summary

Constructors

Constructor and Description
FITSDataNode(DataSource datsrc) Constructs a FITSDataNode from a data source.

Method Summary

Modifier and Type	Method and Description
boolean	allowsChildren() The DefaultDataNode implementation of this method returns false.
protected abstract FITSDataNode.ArrayDataMaker	getArrayData(long start, long size) Returns an ArrayDataMaker encapsulating the same input stream as the on one which this FITSDataNode is based, but starting at a given offset start into the stream and size bytes long.
Iterator	getChildIterator() The DefaultDataNode implementation of this method throws UnsupportedOperationException (DefaultDataNode.allowsChildren() is false).
protected ArrayDataInput	getDataInput() Returns an ArrayDataInput object containing the data from this FITS object.
String	getDescription() Gets a concise description of this object.
String	getName() Gets the name of this object.
String	getNodeTLA() The DefaultDataNode implementation returns the string "...".
String	getNodeType() Returns a short sentence indicating what kind of node this is.
String	getPathSeparator() Returns a default separator string.
static boolean	isMagic(byte[] buffer) Indicates whether a buffer of bytes looks like the start of a FITS file.

Methods inherited from class uk.ac.starlink.datanode.nodes.DefaultDataNode

beep, configureDetail, getChildMaker, getCreator, getDataObject, getIcon, getLabel, getParentObject, getPathElement, hasDataObject, makeChild, makeErrorChild, registerDataObject, setChildMaker, setCreator, setDescription, setIconID, setLabel, setName, setParentObject, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

FITSDataNode

public FITSDataNode(DataSource datsrc)
             throws NoSuchDataException

Constructs a FITSDataNode from a data source.

Parameters:

datsrc - the source of the data

Throws:

NoSuchDataException

Method Detail

getName

public String getName()

Description copied from interface: DataNode

Gets the name of this object. This is an intrinsic property of the object.

Specified by:

getName in interface DataNode

Overrides:

getName in class DefaultDataNode

Returns:

the name of the object

getDescription

public String getDescription()

Description copied from interface: DataNode

Gets a concise description of this object. The form of the description will depend on the type of node, but it might detail the shape or type of data represented, or otherwise give some information additional to the name. It should not include the return value of the getName method, since they may be presented together. It should be on one line, and preferably no longer than around 70 characters. The null value may be returned if there is nothing to say.

Specified by:

getDescription in interface DataNode

Overrides:

getDescription in class DefaultDataNode

Returns:

a short string describing this object

allowsChildren

public boolean allowsChildren()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation of this method returns false.

Specified by:

allowsChildren in interface DataNode

Overrides:

allowsChildren in class DefaultDataNode

Returns:

true if the node is of a type which can have child nodes, false otherwise

getArrayData

protected abstract FITSDataNode.ArrayDataMaker getArrayData(long start,
                                                            long size)

Returns an ArrayDataMaker encapsulating the same input stream as the on one which this FITSDataNode is based, but starting at a given offset start into the stream and size bytes long.

Parameters:

start - the offset into this FITSDataNode's stream at which the returned source's streams should start

size - the number of bytes contained by the returned source's stream

getChildIterator

public Iterator getChildIterator()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation of this method throws UnsupportedOperationException (DefaultDataNode.allowsChildren() is false).

Specified by:

getChildIterator in interface DataNode

Overrides:

getChildIterator in class DefaultDataNode

Returns:

an Iterator over the children. Each object iterated over should be a DataNode. Behaviour is undefined if this method is called on an object for which allowsChildren returns false.

getPathSeparator

public String getPathSeparator()

Description copied from class: DefaultDataNode

Returns a default separator string.

Specified by:

getPathSeparator in interface DataNode

Overrides:

getPathSeparator in class DefaultDataNode

Returns:

"."

getNodeTLA

public String getNodeTLA()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation returns the string "...".

Specified by:

getNodeTLA in interface DataNode

Overrides:

getNodeTLA in class DefaultDataNode

Returns:

"..."

getNodeType

public String getNodeType()

Description copied from interface: DataNode

Returns a short sentence indicating what kind of node this is. The return value should be just a few words. As a rough guideline it should indicate what the implementing class is.

Specified by:

getNodeType in interface DataNode

Overrides:

getNodeType in class DefaultDataNode

Returns:

a short description of the type of this DataNode

getDataInput

protected ArrayDataInput getDataInput()
                               throws IOException

Returns an ArrayDataInput object containing the data from this FITS object.

Throws:

IOException

isMagic

public static boolean isMagic(byte[] buffer)

Indicates whether a buffer of bytes looks like the start of a FITS file.

Parameters:

buffer - the first few bytes of a potential stream

Returns:

true if buffer matches the FITS file magic number