Module org.apache.sis.storage

Package org.apache.sis.storage

Class AbstractFeatureSet

Object

AbstractResource

AbstractFeatureSet

All Implemented Interfaces:

Data­Set, Feature­Set, Resource

Direct Known Subclasses:

Concatenated­Feature­Set, Join­Feature­Set

public abstract class AbstractFeatureSet
extends AbstractResource
implements FeatureSet

Default implementations of several methods for classes that want to implement the Feature­Set interface. Subclasses should override the following methods:

• Feature­Set.get­Type() (mandatory)
• Feature­Set.features(boolean parallel) (mandatory)
• get­Feature­Count() (recommended)
• Abstract­Resource.get­Envelope() (recommended)
• create­Metadata() (optional)

Thread safety

Default methods of this abstract class are thread-safe. Synchronization, when needed, uses Abstract­Resource.get­Synchronization­Lock().

Since:

1.2

Field Summary

Fields inherited from class AbstractResource

listeners

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Abstract­Feature­Set(Store­Listeners parent­Listeners, boolean hidden)	Creates a new resource which can send notifications to the given set of listeners.
protected	Abstract­Feature­Set(Resource parent)	Creates a new resource, potentially as a child of another resource.

Method Summary

Modifier and Type	Method	Description
protected Metadata	create­Metadata()	Invoked in a synchronized block the first time that get­Metadata() is invoked.
Optional­Long	get­Feature­Count()	Returns an estimation of the number of features in this set, or empty if unknown.
Optional<Generic­Name>	get­Identifier()	Returns the feature type name as the identifier for this resource.

Methods inherited from class AbstractResource

add­Listener, clear­Cache, get­Envelope, get­Metadata, get­Synchronization­Lock, remove­Listener

Methods inherited from class Object

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

Methods inherited from interface DataSet

get­Envelope

Methods inherited from interface FeatureSet

features, get­Type, subset

Methods inherited from interface Resource

add­Listener, get­Metadata, remove­Listener

Constructor Details

AbstractFeatureSet

protected AbstractFeatureSet(Resource parent)

Creates a new resource, potentially as a child of another resource. The parent resource is typically, but not necessarily, an Aggregate.

Parameters:

parent - the parent resource, or null if none.

Since:

1.4

AbstractFeatureSet

protected AbstractFeatureSet(StoreListeners parentListeners,
 boolean hidden)

Creates a new resource which can send notifications to the given set of listeners. If hidden is false (the recommended value), then this resource will have its own set of listeners with this resource declared as the source of events. It will be possible to add and remove listeners independently from the set of parent listeners. Conversely if hidden is true, then the given listeners will be used directly and this resource will not appear as the source of any event.

In any cases, the listeners of all parents (ultimately the data store that created this resource) will always be notified, either directly if hidden is true or indirectly if hidden is false.

Parameters:

parent­Listeners - listeners of the parent resource, or null if none. This is usually the listeners of the Data­Store that created this resource.

hidden - false if this resource shall use its own Store­Listeners with the specified parent, or true for using parent­Listeners directly.

Method Details

getIdentifier

public Optional<GenericName> getIdentifier()
                                    throws DataStoreException

Returns the feature type name as the identifier for this resource. Subclasses should override if they can provide a more specific identifier.

Specified by:

get­Identifier in interface Resource

Overrides:

get­Identifier in class Abstract­Resource

Returns:

the resource identifier inferred from feature type.

Throws:

Data­Store­Exception - if an error occurred while fetching the identifier.

See Also:

• Data­Store.get­Identifier()

getFeatureCount

public OptionalLong getFeatureCount()

Returns an estimation of the number of features in this set, or empty if unknown. The default implementation returns an empty value.

Returns:

estimation of the number of features.

createMetadata

protected Metadata createMetadata()
                           throws DataStoreException

Invoked in a synchronized block the first time that get­Metadata() is invoked. The default implementation populates metadata based on information provided by get­Identifier(), get­Envelope(), get­Type() and get­Feature­Count(). Subclasses should override if they can provide more information. The default value can be completed by casting to Default­Metadata.

Overrides:

create­Metadata in class Abstract­Resource

Returns:

the newly created metadata, or null if unknown.

Throws:

Data­Store­Exception - if an error occurred while reading metadata from this resource.