org.das2.catalog

Interface DasNode

All Known Subinterfaces:

DasDirNode, DasSrcNode

All Known Implementing Classes:

AbstractDirNode, AbstractNode, AbstractSrcNode, HttpGetSrcNode

public interface DasNode

A single node from the das2 federated catalog, which may, or may not, be fully realized from source data.

Method Summary

Modifier and Type	Method and Description
DasNode	getRoot() Return the highest node reachable by this catalog node.
boolean	isDir() Can this catalog node have the sub-nodes?
boolean	isInfo() Is this object an information node.
boolean	isLoaded() Does this node have a full definition
boolean	isRoot() Is this object a detached root of a catalog tree.
boolean	isSrc() Can this catalog node provide data
void	load(ProgressMonitor mon) Phase 2 construction for the node.
java.lang.String	name() get the node name
java.lang.String	path() get the node path
DasProp	prop(java.lang.String sFragment) Get a property of a node
DasProp	prop(java.lang.String sFragment, java.lang.Object oDefault) Get a property of the node, or the default Similar to sub-page references for web-pages, property values are retrieved by providing a fragment path.
java.lang.String	toString() A summary of the node
java.lang.String	type() Get the node type.

Method Detail

type

java.lang.String type()

Get the node type.

Returns:

A string representing the node type

name

java.lang.String name()

get the node name

Returns:

The human readable name of the node, not it's path ID

path

java.lang.String path()

get the node path

Returns:

The catalog path to this node. For root nodes this is null

toString

java.lang.String toString()

A summary of the node

Overrides:

toString in class java.lang.Object

Returns:

A short string describing the node, not an info dump of the contents

isRoot

boolean isRoot()

Is this object a detached root of a catalog tree. Note that the build in root URLs are always detached roots because there is no higher node to find. A detached source or info node can still be a root node without also being a directory.

Returns:

true if no higher node is reachable from this one.

isSrc

boolean isSrc()

Can this catalog node provide data

Returns:

true if this node describes one or more data sources

isDir

boolean isDir()

Can this catalog node have the sub-nodes?

Returns:

true if this node can have child nodes, not that it necessarily contains any.

isInfo

boolean isInfo()

Is this object an information node.

Returns:

true if this node in the catalog provides a description of a mission, spacecraft, instrument, person or any other item category

getRoot

DasNode getRoot()

Return the highest node reachable by this catalog node.

Returns:

the highest node reachable by this catalog node, which may just be itself.

isLoaded

boolean isLoaded()

Does this node have a full definition

Returns:

True if this node successfully passed the second construction stage.

load

void load(ProgressMonitor mon)
   throws DasResolveException

Phase 2 construction for the node. DasNode objects exist to represent remote catalog data. Since one catalog node can point to others, it is possible to create a stub node that knows how to load itself, but is not actually loaded yet. This function can be used to trigger full catalog node resolution. This will trigger a re-load if the node is already loaded.

Parameters:

mon - A human amusement device incase network operations are taking a while.

Throws:

DasResolveException

prop

DasProp prop(java.lang.String sFragment,
             java.lang.Object oDefault)

Get a property of the node, or the default Similar to sub-page references for web-pages, property values are retrieved by providing a fragment path. Fragment paths are standardized using the '/' as the sub-item separator. By combining node paths with fragment paths every single property value within the global catalog system has a unique URI. For example: :tag:das2.org,2012:site:/uiowa/voyager/1/pws#interface/coords/time/max/value ^ ^ ^ ^ ^ | | | | | | | | +- path +- fragment | | +- date | +- authority +-- scheme The purpose of this function is to retrieve properties from within a node given a fragment string.

Parameters:

sFragment - The fragment path, for example "tech_contact/0/email"

oDefault - The default object to return if nothing exists at the fragment location. The object will be wrapped as a DasProp, so it must be null or one of the accepted object types defined for constructing DasProp objects.

Returns:

A DasProp. If load has not been called for this node, the return will always be the default.

prop

DasProp prop(java.lang.String sFragment)

Get a property of a node

Parameters:

sFragment -

Returns:

The property at the given fragment location or null DasProp if the given path does not lead to a property. If load() has not been called for this node the return will always be null.