uk.ac.starlink.datanode.nodes

Class HDSDataNode

java.lang.Object

uk.ac.starlink.datanode.nodes.DefaultDataNode

uk.ac.starlink.datanode.nodes.HDSDataNode

All Implemented Interfaces:

DataNode

Direct Known Subclasses:

ARYDataNode, NDFDataNode

public class HDSDataNode
extends DefaultDataNode

A DataNode representing an HDS object.

Version:

$Id$

Author:

Mark Taylor (Starlink)

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_CHILDREN_PER_ARRAY The maximum number of cells of an array of structures to be considered as its children - more could be unwieldy.

Constructor Summary

Constructors

Constructor and Description
HDSDataNode(File file) Constructs an HDSDataNode from the file name of a container file.
HDSDataNode(HDSObject hobj) Constructs an HDSDataNode from an HDSObject.
HDSDataNode(String path) Constructs an HDSDataNode from an HDS path.

Method Summary

Modifier and Type	Method and Description
boolean	allowsChildren() Indicates whether this node allows child nodes or not.
void	configureDetail(DetailViewer dv) No custom configuration is performed.
Iterator	getChildIterator() Returns the children of this node.
Object	getDataObject(DataType dtype) The DefaultDataNode implementation returns any data object which has been registered using DefaultDataNode.registerDataObject(uk.ac.starlink.datanode.nodes.DataType, java.lang.Object).
String	getDescription() Gets a concise description of this object.
protected static HDSObject	getHDSFromFile(File file)
protected static HDSObject	getHDSFromPath(String path)
String	getName() Gets the name of this object.
String	getNodeTLA() Returns the string "HDS".
String	getNodeType() Returns a short sentence indicating what kind of node this is.
Object	getParentObject() Returns an object which is in some sense the parent of the one this node is based on.
String	getPathElement() The DefaultDataNode implementation returns the label as a default path element.
String	getPathSeparator() Returns a default separator string.
boolean	hasDataObject(DataType dtype) The DefaultDataNode implementation returns true for only those data objects which have been registered using DefaultDataNode.registerDataObject(uk.ac.starlink.datanode.nodes.DataType, java.lang.Object).
static boolean	isMagic(byte[] magic)

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

beep, getChildMaker, getCreator, getIcon, getLabel, 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

Field Detail

MAX_CHILDREN_PER_ARRAY

public static final int MAX_CHILDREN_PER_ARRAY

The maximum number of cells of an array of structures to be considered as its children - more could be unwieldy. Actually this doesn't need to be either static or final, it just feels like a constant.

See Also:

Constant Field Values

Constructor Detail

HDSDataNode

public HDSDataNode(HDSObject hobj)
            throws NoSuchDataException

Constructs an HDSDataNode from an HDSObject.

Throws:

NoSuchDataException

HDSDataNode

public HDSDataNode(File file)
            throws NoSuchDataException

Constructs an HDSDataNode from the file name of a container file.

Throws:

NoSuchDataException

HDSDataNode

public HDSDataNode(String path)
            throws NoSuchDataException

Constructs an HDSDataNode from an HDS path.

Throws:

NoSuchDataException

Method Detail

getHDSFromPath

protected static HDSObject getHDSFromPath(String path)
                                   throws NoSuchDataException

Throws:

NoSuchDataException

getHDSFromFile

protected static HDSObject getHDSFromFile(File file)
                                   throws NoSuchDataException

Throws:

NoSuchDataException

allowsChildren

public boolean allowsChildren()

Indicates whether this node allows child nodes or not. We consider that an HDSDataNode may allow children in two ways: it may either be a scalar structure, in which case its children will be its components, or it may be an array of structures, in which case its children will be the elements of the array. Here the term structure is used in the HDS sense.

We do not consider the elements of an array to be children if the if there are 'too many' elements (more than MAX_CHILDREN_PER_ARRAY). This is arbitrary, but is intended to prevent display getting too unwieldy.

Another possibility would be to allow the elements of an array of primitives to be considered as elements. Following the (sensible) behaviour of HDSTRACE We don't do this.

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

getChildIterator

public Iterator getChildIterator()

Returns the children of this node. This will either be the components of a scalar structure, or the elements of an array of structures.

Specified by:

getChildIterator in interface DataNode

Overrides:

getChildIterator in class DefaultDataNode

Returns:

an array of DataNodes considered to be the children of this node

getParentObject

public Object getParentObject()

Description copied from interface: DataNode

Returns an object which is in some sense the parent of the one this node is based on. The parent is not a DataNode, it is something which may get fed to a DataNodeFactory to create DataNode. If no such object exists, which may well be the case, null should be returned.

Specified by:

getParentObject in interface DataNode

Overrides:

getParentObject in class DefaultDataNode

Returns:

an object which is the parent of this one, or null

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

getPathElement

public String getPathElement()

Description copied from class: DefaultDataNode

The DefaultDataNode implementation returns the label as a default path element.

Specified by:

getPathElement in interface DataNode

Overrides:

getPathElement in class DefaultDataNode

Returns:

the node's label

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:

"."

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

getNodeTLA

public String getNodeTLA()

Returns the string "HDS".

Specified by:

getNodeTLA in interface DataNode

Overrides:

getNodeTLA in class DefaultDataNode

Returns:

"HDS"

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

configureDetail

public void configureDetail(DetailViewer dv)

Description copied from class: DefaultDataNode

No custom configuration is performed.

Specified by:

configureDetail in interface DataNode

Overrides:

configureDetail in class DefaultDataNode

Parameters:

dv - the detail viewer which this node is given an opportunity to configure

hasDataObject

public boolean hasDataObject(DataType dtype)

Description copied from class: DefaultDataNode

The DefaultDataNode implementation returns true for only those data objects which have been registered using DefaultDataNode.registerDataObject(uk.ac.starlink.datanode.nodes.DataType, java.lang.Object).

Specified by:

hasDataObject in interface DataNode

Overrides:

hasDataObject in class DefaultDataNode

Parameters:

dtype - data object type of interest

Returns:

true iff a subsequent call of getDataObject(type) is likely to be successful

getDataObject

public Object getDataObject(DataType dtype)
                     throws DataObjectException

Description copied from class: DefaultDataNode

The DefaultDataNode implementation returns any data object which has been registered using DefaultDataNode.registerDataObject(uk.ac.starlink.datanode.nodes.DataType, java.lang.Object).

Specified by:

getDataObject in interface DataNode

Overrides:

getDataObject in class DefaultDataNode

Parameters:

dtype - data object type of interest

Returns:

data object of type type

Throws:

DataObjectException

isMagic

public static boolean isMagic(byte[] magic)