gov.nasa.worldwind.layers
Class AbstractLayer

java.lang.Object
  gov.nasa.worldwind.avlist.AVListImpl
      gov.nasa.worldwind.WWObjectImpl
          gov.nasa.worldwind.layers.AbstractLayer

All Implemented Interfaces:

AVList, Disposable, MessageListener, Layer, Restorable, WWObject, PropertyChangeListener, EventListener

Direct Known Subclasses:

AbstractAirspaceEditor, AbstractGraticuleLayer, AbstractShapeEditor, AirspaceLayer, AnnotationLayer, CachedRenderableLayer, CompassLayer, CrosshairLayer, GliderImageLayer, IconLayer, MarkerLayer, MercatorTiledImageLayer, PlaceNameLayer, RenderableLayer, ScalebarLayer, SegmentPlaneEditor, SkyGradientLayer, StatusLayer, TerrainProfileLayer, TiledImageLayer, WorldMapLayer

public abstract class AbstractLayer
extends WWObjectImpl
implements Layer

Constructor Summary

AbstractLayer()

Method Summary

static Element	createLayerConfigElements(AVList params, Element context) Appends layer configuration parameters as elements to the specified context.
void	dispose() Disposes of any internal resources allocated by the object.
protected void	doPick(DrawContext dc, Point point)
protected void	doPreRender(DrawContext dc)
protected abstract void	doRender(DrawContext dc)
FileStore	getDataFileStore()
long	getExpiryTime() Returns the current expiry time.
static AVList	getLayerConfigParams(Element domElement, AVList params) Parses layer configuration parameters from the specified DOM document.
double	getMaxActiveAltitude() Returns the maximum altitude at which to display the layer.
Double	getMaxEffectiveAltitude(Double radius) Indicates the altitude above which this layer likely has low value or is not expected to be active.
double	getMinActiveAltitude() Returns the minimum altitude at which the layer is displayed.
Double	getMinEffectiveAltitude(Double radius) Indicates the altitude below which this layer likely has low value or is not expected to be active.
String	getName() Returns the layer's name, as specified in the most recent call to Layer.setName(java.lang.String).
double	getOpacity() Returns the layer's opacity, the degree to which it is blended with underlying layers.
String	getRestorableState() Returns an XML document string describing the object's state.
double	getScale() Returns the map scale, in terms of the ratio of 1 to the value returned, e.g., 1:24000.
protected ScreenCredit	getScreenCredit()
boolean	isAtMaxResolution() Indicates whether the most recent rendering of the layer rendered the highest resolution imagery or other data available.
boolean	isEnabled() Indicates whether the layer is enabled for rendering and selection.
boolean	isLayerActive(DrawContext dc) Indicates whether the layer is active based on arbitrary criteria.
static boolean	isLayerConfigDocument(Element domElement) Returns true if a specified DOM document is a Layer configuration document, and false otherwise.
boolean	isLayerInView(DrawContext dc) Indicates whether the layer is in the view.
boolean	isMultiResolution() Indicates whether the layer provides multiple resolutions of imagery or other data.
boolean	isNetworkRetrievalEnabled() Indicates whether the layer is allowed to retrieve data from the network.
boolean	isPickEnabled() Indicates whether the layer performs selection during picking.
void	pick(DrawContext dc, Point point) Cause the layer to perform picking, which determines whether the object or its components intersect a given point on the screen.
void	preRender(DrawContext dc) Causes the layer to perform any actions necessary to subsequently render the layer.
void	render(DrawContext dc) Cause the layer to draw its representation.
void	restoreState(String stateInXml) Restores the object's state to what is described in the specified XML document string.
void	setDataFileStore(FileStore fileStore)
void	setEnabled(boolean enabled) Controls whether the layer is enabled for rendering and selection.
void	setExpiryTime(long expiryTime) Specifies the time of the layer's most recent dataset update.
void	setMaxActiveAltitude(double maxActiveAltitude) Specifies the maximum altitude at which to display the layer.
void	setMinActiveAltitude(double minActiveAltitude) Specifies the minimum altitude at which to display the layer.
void	setName(String name) Set the layer's name.
void	setNetworkRetrievalEnabled(boolean networkDownloadEnabled) Controls whether the layer is allowed to retrieve data from the network.
void	setOpacity(double opacity) Sets the layer's opacity, the degree to which it is blended with underlying layers.
void	setPickEnabled(boolean pickable) Controls whether the layer should perform picking.
protected void	setScreenCredit(ScreenCredit screenCredit)
String	toString()

Methods inherited from class gov.nasa.worldwind.WWObjectImpl

onMessage, propertyChange

Methods inherited from class gov.nasa.worldwind.avlist.AVListImpl

addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getBooleanValue, getBooleanValue, getChangeSupport, getDoubleValue, getDoubleValue, getEntries, getIntegerValue, getIntegerValue, getLongValue, getLongValue, getRestorableStateForAVPair, getStringValue, getStringValue, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

Methods inherited from class java.lang.Object

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

Methods inherited from interface gov.nasa.worldwind.avlist.AVList

addPropertyChangeListener, addPropertyChangeListener, clearList, copy, firePropertyChange, firePropertyChange, getEntries, getStringValue, getValue, getValues, hasKey, removeKey, removePropertyChangeListener, removePropertyChangeListener, setValue, setValues

Methods inherited from interface java.beans.PropertyChangeListener

propertyChange

Methods inherited from interface gov.nasa.worldwind.event.MessageListener

onMessage

Constructor Detail

AbstractLayer

public AbstractLayer()

Method Detail

createLayerConfigElements

public static Element createLayerConfigElements(AVList params,
                                                Element context)

Appends layer configuration parameters as elements to the specified context. This appends elements for the following parameters:

Parameter	Element Path	Type
AVKey.DISPLAY_NAME	DisplayName	String
AVKey.OPACITY	Opacity	Double
AVKey.MAX_ACTIVE_ALTITUDE	ActiveAltitudes/@max	Double
AVKey.MIN_ACTIVE_ALTITUDE	ActiveAltitudes/@min	Double
AVKey.NETWORK_RETRIEVAL_ENABLED	NetworkRetrievalEnabled	Boolean
AVKey.MAP_SCALE	MapScale	Double
AVKey.SCREEN_CREDIT	ScreenCredit	ScreenCredit

Parameters:

params - the key-value pairs which define the layer configuration parameters.

context - the XML document root on which to append layer configuration elements.

Returns:

a reference to context.

Throws:

IllegalArgumentException - if either the parameters or the context are null.

dispose

public void dispose()

Description copied from interface: Disposable

Disposes of any internal resources allocated by the object.

Specified by:

dispose in interface Disposable

doPick

protected void doPick(DrawContext dc,
                      Point point)

doPreRender

protected void doPreRender(DrawContext dc)

doRender

protected abstract void doRender(DrawContext dc)

getDataFileStore

public FileStore getDataFileStore()

getExpiryTime

public long getExpiryTime()

Description copied from interface: Layer

Returns the current expiry time.

Specified by:

getExpiryTime in interface Layer

Returns:

the current expiry time.

getLayerConfigParams

public static AVList getLayerConfigParams(Element domElement,
                                          AVList params)

Parses layer configuration parameters from the specified DOM document. This writes output as key-value pairs to params. If a parameter from the XML document already exists in params, that parameter is ignored. Supported key and parameter names are:

Parameter	Element Path	Type
AVKey.DISPLAY_NAME	DisplayName	String
AVKey.OPACITY	Opacity	Double
AVKey.MAX_ACTIVE_ALTITUDE	ActiveAltitudes/@max	Double
AVKey.MIN_ACTIVE_ALTITUDE	ActiveAltitudes/@min	Double
AVKey.NETWORK_RETRIEVAL_ENABLED	NetworkRetrievalEnabled	Boolean
AVKey.MAP_SCALE	MapScale	Double
AVKey.SCREEN_CREDIT	ScreenCredit	ScreenCredit

Parameters:

domElement - the XML document root to parse for layer configuration elements.

params - the output key-value pairs which recieve the layer configuration parameters. A null reference is permitted.

Returns:

a reference to params, or a new AVList if params is null.

Throws:

IllegalArgumentException - if the document is null.

getMaxActiveAltitude

public double getMaxActiveAltitude()

Description copied from interface: Layer

Returns the maximum altitude at which to display the layer.

Specified by:

getMaxActiveAltitude in interface Layer

Returns:

the maximum altitude at which to display the layer.

getMaxEffectiveAltitude

public Double getMaxEffectiveAltitude(Double radius)

Description copied from interface: Layer

Indicates the altitude above which this layer likely has low value or is not expected to be active. This value is independent of the maximum active altitude, Layer.setMaxActiveAltitude(double) and does not reflect it.

The returned altitude is valid when the field of view indicated by View.getFieldOfView() is set to its default value. Changing the field of view to any value other than the default may change this layer's maximum effective altitude, but the returned altitude will not reflect that change.

Specified by:

getMaxEffectiveAltitude in interface Layer

Parameters:

radius - the radius of the Globe the layer is associated with. May be null, in which case the Earth's equatorial radius is used, Earth.WGS84_EQUATORIAL_RADIUS.

Returns:

the layer's maximum effective altitude.

getMinActiveAltitude

public double getMinActiveAltitude()

Description copied from interface: Layer

Returns the minimum altitude at which the layer is displayed.

Specified by:

getMinActiveAltitude in interface Layer

Returns:

the minimum altitude at which the layer is displayed.

getMinEffectiveAltitude

public Double getMinEffectiveAltitude(Double radius)

Description copied from interface: Layer

Indicates the altitude below which this layer likely has low value or is not expected to be active. This value is independent of the minimum active altitude, Layer.setMinActiveAltitude(double) and does not reflect it.

The returned altitude is valid when the field of view indicated by View.getFieldOfView() is set to its default value. Changing the field of view to any value other than the default may change this layer's minimum effective altitude, but the returned altitude will not reflect that change.

Specified by:

getMinEffectiveAltitude in interface Layer

Parameters:

radius - the radius of the Globe the layer is associated with. May be null, in which case the Earth's equatorial radius is used, Earth.WGS84_EQUATORIAL_RADIUS.

Returns:

the layer's minimum effective altitude.

getName

public String getName()

Description copied from interface: Layer

Returns the layer's name, as specified in the most recent call to Layer.setName(java.lang.String).

Specified by:

getName in interface Layer

Returns:

the layer's name.

getOpacity

public double getOpacity()

Description copied from interface: Layer

Returns the layer's opacity, the degree to which it is blended with underlying layers.

Many layers apply special usage of opacity, and some ignore it in favor of the opacity settings of their internal renderables. See the description of this method in specific layers to determine usage there.

Specified by:

getOpacity in interface Layer

Returns:

The layer's opacity, a value between 0 and 1.

getRestorableState

public String getRestorableState()

Description copied from interface: Restorable

Returns an XML document string describing the object's state. This state can be restored later by calling restoreState and passing the XML document.

Specified by:

getRestorableState in interface Restorable

Returns:

an XML document string describing the object's state.

getScale

public double getScale()

Description copied from interface: Layer

Returns the map scale, in terms of the ratio of 1 to the value returned, e.g., 1:24000.

Specified by:

getScale in interface Layer

Returns:

the map scale.

getScreenCredit

protected ScreenCredit getScreenCredit()

isAtMaxResolution

public boolean isAtMaxResolution()

Description copied from interface: Layer

Indicates whether the most recent rendering of the layer rendered the highest resolution imagery or other data available. Some layers do not track resolution. For those layers this value will always be true. Typically such layers also return false from Layer.isMultiResolution().

Specified by:

isAtMaxResolution in interface Layer

Returns:

true if the layer is at maximum resolution, otherwise false.

isEnabled

public boolean isEnabled()

Description copied from interface: Layer

Indicates whether the layer is enabled for rendering and selection.

Specified by:

isEnabled in interface Layer

Returns:

true if the layer is enabled, else false.

isLayerActive

public boolean isLayerActive(DrawContext dc)

Description copied from interface: Layer

Indicates whether the layer is active based on arbitrary criteria. The method implemented here is a default indicating the layer is active if the current altitude is within the layer's min and max active altitudes. Subclasses able to consider more criteria should override this implementation.

Specified by:

isLayerActive in interface Layer

Parameters:

dc - the current draw context

Returns:

true if the layer is active, false otherwise.

isLayerConfigDocument

public static boolean isLayerConfigDocument(Element domElement)

Returns true if a specified DOM document is a Layer configuration document, and false otherwise.

Parameters:

domElement - the DOM document in question.

Returns:

true if the document is a Layer configuration document; false otherwise.

Throws:

IllegalArgumentException - if document is null.

isLayerInView

public boolean isLayerInView(DrawContext dc)

Description copied from interface: Layer

Indicates whether the layer is in the view. The method implemented here is a default indicating the layer is in view. Subclasses able to determine their presence in the view should override this implementation.

Specified by:

isLayerInView in interface Layer

Parameters:

dc - the current draw context

Returns:

true if the layer is in the view, false otherwise.

isMultiResolution

public boolean isMultiResolution()

Description copied from interface: Layer

Indicates whether the layer provides multiple resolutions of imagery or other data.

Specified by:

isMultiResolution in interface Layer

Returns:

true if the layer provides multiple resolutions, else false.

isNetworkRetrievalEnabled

public boolean isNetworkRetrievalEnabled()

Description copied from interface: Layer

Indicates whether the layer is allowed to retrieve data from the network. Many layers have no need to retrieve data from the network. This state is meaningless for such layers.

Specified by:

isNetworkRetrievalEnabled in interface Layer

Returns:

true if the layer is enabled to retrieve network data, else false.

isPickEnabled

public boolean isPickEnabled()

Description copied from interface: Layer

Indicates whether the layer performs selection during picking.

Most layers enable picking by default. However, this becomes inconvenient for SurfaceImage and SurfaceImageLayer} when the image covers a large area because the view input handlers detect the surface image rather than the terrain as the top picked object, and will not respond to the user's attempts at navigation. The solution is to disable picking for the layer.

Specified by:

isPickEnabled in interface Layer

Returns:

true if picking is enabled, else false.

pick

public void pick(DrawContext dc,
                 Point point)

Description copied from interface: Layer

Cause the layer to perform picking, which determines whether the object or its components intersect a given point on the screen. Objects that intersect that point are added to the draw context's pick list and are conveyed to the application via selection events or by a direct query of WorldWindow.getObjectsAtCurrentPosition().

Specified by:

pick in interface Layer

Parameters:

dc - the current draw context for rendering.

point - the screen coordinate point

See Also:

SelectEvent

preRender

public void preRender(DrawContext dc)

Description copied from interface: Layer

Causes the layer to perform any actions necessary to subsequently render the layer. The layer has exclusive access to the frame buffer during the call, and may use it to generate images or other information that is subsequently used to render the layer's contents. Upon return, the OpenGL state must be restored to its original.

Specified by:

preRender in interface Layer

Parameters:

dc - the current draw context.

render

public void render(DrawContext dc)

Description copied from interface: Layer

Cause the layer to draw its representation.

Specified by:

render in interface Layer

Parameters:

dc - the current draw context

Throws:

IllegalArgumentException - if dc is null, or dc's Globe or View is null

restoreState

public void restoreState(String stateInXml)

Description copied from interface: Restorable

Restores the object's state to what is described in the specified XML document string.

Specified by:

restoreState in interface Restorable

Parameters:

stateInXml - an XML document string describing an object's state.

setDataFileStore

public void setDataFileStore(FileStore fileStore)

setEnabled

public void setEnabled(boolean enabled)

Description copied from interface: Layer

Controls whether the layer is enabled for rendering and selection.

Specified by:

setEnabled in interface Layer

Parameters:

enabled - true if the layer is enabled, else false.

setExpiryTime

public void setExpiryTime(long expiryTime)

Description copied from interface: Layer

Specifies the time of the layer's most recent dataset update. If greater than zero, the layer ignores and eliminates any previously cached data older than the time specified, and requests new information from the data source. If zero, the layer uses any expiry times intrinsic to the layer, typically initialized at layer construction. The default expiry time is 0, thereby enabling a layer's intrinsic expiration criteria.

Specified by:

setExpiryTime in interface Layer

Parameters:

expiryTime - the expiry time of any cached data, expressed as a number of milliseconds beyond the epoch.

See Also:

for a description of milliseconds beyond the epoch.

setMaxActiveAltitude

public void setMaxActiveAltitude(double maxActiveAltitude)

Description copied from interface: Layer

Specifies the maximum altitude at which to display the layer.

Specified by:

setMaxActiveAltitude in interface Layer

Parameters:

maxActiveAltitude - the maximum altitude at which to display the layer.

setMinActiveAltitude

public void setMinActiveAltitude(double minActiveAltitude)

Description copied from interface: Layer

Specifies the minimum altitude at which to display the layer.

Specified by:

setMinActiveAltitude in interface Layer

Parameters:

minActiveAltitude - the minimum altitude at which to display the layer.

setName

public void setName(String name)

Description copied from interface: Layer

Set the layer's name. The name is a convenience attribute typically used to identify the layer in user interfaces. By default, a layer has no name.

Specified by:

setName in interface Layer

Parameters:

name - the name to assign to the layer.

setNetworkRetrievalEnabled

public void setNetworkRetrievalEnabled(boolean networkDownloadEnabled)

Description copied from interface: Layer

Controls whether the layer is allowed to retrieve data from the network. Many layers have no need for data from the network. This state may be set but is meaningless for such layers.

Specified by:

setNetworkRetrievalEnabled in interface Layer

Parameters:

networkDownloadEnabled - true if network retrieval is allowed, else false.

setOpacity

public void setOpacity(double opacity)

Description copied from interface: Layer

Sets the layer's opacity, the degree to which it is blended with underlying layers.

Many layers apply special usage of opacity, and some ignore it in favor of the opacity settings of their internal renderables. See the description of this method in specific layers to determine usage there.

Specified by:

setOpacity in interface Layer

Parameters:

opacity - The layer opacity, a value between 0 and 1. 0 indicates non-opaque (fully transparent), 1 indicates fully opaque. Values between 0 and 1 indicate partial opacity.

setPickEnabled

public void setPickEnabled(boolean pickable)

Description copied from interface: Layer

Controls whether the layer should perform picking.

Specified by:

setPickEnabled in interface Layer

Parameters:

pickable - true if the layer should perform picking, else false.

setScreenCredit

protected void setScreenCredit(ScreenCredit screenCredit)

toString

public String toString()

Overrides:

toString in class Object