org.geotools.mbstyle.layer

Class MBLayer

Object

MBLayer

Direct Known Subclasses:

BackgroundMBLayer, CircleMBLayer, FillExtrusionMBLayer, FillMBLayer, LineMBLayer, RasterMBLayer, SymbolMBLayer

public abstract class MBLayer
extends Object

MBLayer wrapper (around one of the MBStyle layers).

All methods act as accessors on provided JSON layer, no other state is maintained. This allows modifications to be made cleanly with out chance of side-effect.

• get methods: access the json directly
• query methods: provide logic / transforms to GeoTools classes as required.

In the normal course of events MBLayer is constructed as a flyweight object by MBStyle to provide easy access to its layers list.

Author:

Torben Barsballe (Boundless)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MBLayer.Visibility Whether this layer is displayed.

Field Summary

Fields

Modifier and Type	Field and Description
protected FilterFactory2	ff Shared filter factory
protected String	id field access for "id" key (due to its use in error messages)
protected JSONObject	json JSON layer being wrapped.
protected MBObjectParser	parse Helper class used to provide json access and expression / filter conversions
protected StyleFactory2	sf Shared style factory

Constructor Summary

Constructors

Constructor and Description
MBLayer(JSONObject json, MBObjectParser parse)

Method Summary

Modifier and Type	Method and Description
static MBLayer	create(JSONObject layer) Factory method creating the appropriate MBStyle based on the "type" indicated in the layer JSON.
boolean	equals(Object obj) Equality based on wrapped json.
Filter	filter() The "filter" as a GeoTools Filter suitable for feature selection, as defined by getFilter().
MBFilter	getFilter() A MBFilter wrapping optional json specifying conditions on source features.
String	getId() Unique layer name.
JSONObject	getJson()
JSONObject	getLayout() Layout properties for the layer.
int	getMaxZoom() The maximum zoom level on which the layer gets parsed and appears on.
JSONObject	getMetadata() Arbitrary properties useful to track with the layer, but do not influence rendering.
int	getMinZoom() The minimum zoom level on which the layer gets parsed and appears on.
JSONObject	getPaint() Default paint properties for this layer.
String	getRef() References another layer to copy type, source, source-layer, minzoom, maxzoom, filter, and layout properties from.
String	getSource() Name of a source description to be used for this layer.
String	getSourceLayer() Layer to use from a vector tile source.
abstract String	getType() Rendering type of this layer.
MBLayer.Visibility	getVisibility() Layout setting - whether this layer is displayed.
int	hashCode() Hashcode based on wrapped json.
JSONObject	layout() Query for layout information (making use of getRef() if available).
JSONObject	paint() Query for paint information (making use of getRef() if available).
String	toString()
List<FeatureTypeStyle>	transform(MBStyle styleContext) Transforms a given MBLayer to a GeoTools FeatureTypeStyle.
List<FeatureTypeStyle>	transform(MBStyle styleContext, Double minScaleDenominator, Double maxScaleDenominator) Transforms a given MBLayer to a GeoTools FeatureTypeStyle.
abstract List<FeatureTypeStyle>	transformInternal(MBStyle styleContext)
boolean	visibility() Whether this layer is displayed.

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

parse

protected final MBObjectParser parse

Helper class used to provide json access and expression / filter conversions

ff

protected final FilterFactory2 ff

Shared filter factory

sf

protected final StyleFactory2 sf

Shared style factory

json

protected final JSONObject json

JSON layer being wrapped.

id

protected final String id

field access for "id" key (due to its use in error messages)

Constructor Detail

MBLayer

public MBLayer(JSONObject json,
               MBObjectParser parse)

Method Detail

create

public static MBLayer create(JSONObject layer)

Factory method creating the appropriate MBStyle based on the "type" indicated in the layer JSON.

Parameters:

layer - JSON Layer definition

Returns:

Generated MBLayer subclass

getType

public abstract String getType()

Rendering type of this layer.

One of:

• fill:A filled polygon with an optional stroked border.
• line: A stroked line.
• symbol: An icon or a text label.
• circle:A filled circle.
• fill-extrusion: An extruded (3D) polygon.
• raster: Raster map textures such as satellite imagery.
• background: The background color or pattern of the map.

Returns:

One of fill, line, symbol, circle, fill-extrusion, raster, background.

getMetadata

public JSONObject getMetadata()

Arbitrary properties useful to track with the layer, but do not influence rendering. Properties should be prefixed to avoid collisions, like 'mapbox:' and 'gt:`.

Returns:

Arbitrary properties useful to track with the layer.

getRef

public String getRef()

References another layer to copy type, source, source-layer, minzoom, maxzoom, filter, and layout properties from. This allows the layers to share processing and be more efficient.

Returns:

References another layer to copy type, source, source-layer, minzoom, maxzoom, filter, and layout properties from.

getJson

public JSONObject getJson()

getId

public String getId()

Unique layer name.

Returns:

layer name, required field

getSource

public String getSource()

Name of a source description to be used for this layer.

While this value is optional, it may be obtained via getRef() if needed.

Returns:

name of source description to be used for this layer, or null if the style has no source.

getSourceLayer

public String getSourceLayer()

Layer to use from a vector tile source. Required if the source supports multiple layers.

While this value is optional, it may be obtained via getRef() if needed.

Returns:

layer to use from a vector tile source, or null if the style has no source-layer.

getMinZoom

public int getMinZoom()

The minimum zoom level on which the layer gets parsed and appears on.

Returns:

minimum zoom level, or Integer.MIN_VALUE if the style has no minzoom.

getMaxZoom

public int getMaxZoom()

The maximum zoom level on which the layer gets parsed and appears on.

Returns:

maximum zoom level, or Integer.MAX_VALUE if the style has no maxzoom.

getFilter

public MBFilter getFilter()

A MBFilter wrapping optional json specifying conditions on source features. Only features that match the filter are displayed. This is available as a GeoTools Filter via filter().

Returns:

MBFilter expression specifying conditions on source features.

filter

public Filter filter()

The "filter" as a GeoTools Filter suitable for feature selection, as defined by getFilter().

Returns:

Filter, or Filter.INCLUDE if the style has no filter.

getLayout

public JSONObject getLayout()

Layout properties for the layer.

Layout properties appear in the layer's "layout" object. They are applied early in the rendering process and define how data for that layer is passed to the renderer. For efficiency, a layer can share layout properties with another layer via the "ref" layer property, and should do so where possible. This will decrease processing time and allow the two layers will share GPU memory and other resources associated with the layer.

Returns:

Layout properties defined for layer, or an empty JSONObject if no layout properties are defined for the style.

layout

public JSONObject layout()

Query for layout information (making use of getRef() if available).

Returns:

Layout properties to use for this layer.

getPaint

public JSONObject getPaint()

Default paint properties for this layer.

Paint properties are applied later in the rendering process. A layer that shares layout properties with another layer can have independent paint properties. Paint properties appear in the layer's "paint" object.

Returns:

Default paint properties for this layer, or an empty JSONObject if no paint properties are defined for the style.

getVisibility

public MBLayer.Visibility getVisibility()

Layout setting - whether this layer is displayed.

Returns:

One of visible, none. Defaults to visible if not defined in the style.

visibility

public boolean visibility()

Whether this layer is displayed.

Returns:

Whether the layout is visible. Defaults to true.

paint

public JSONObject paint()

Query for paint information (making use of getRef() if available).

Returns:

Paint properties to use for this layer.

transform

public List<FeatureTypeStyle> transform(MBStyle styleContext,
                                        Double minScaleDenominator,
                                        Double maxScaleDenominator)

Transforms a given MBLayer to a GeoTools FeatureTypeStyle.

Parameters:

styleContext - The MBStyle to which this layer belongs, used to resolving sprite and glyph names to full urls.

minScaleDenominator - Used to determine zoom level restrictions for generated rules

maxScaleDenominator - Used to determine zoom level restrictions for generated rules

Returns:

A feature type style from the provided layer, or null if the visibility of that layer is false.

transform

public final List<FeatureTypeStyle> transform(MBStyle styleContext)

Transforms a given MBLayer to a GeoTools FeatureTypeStyle.

Parameters:

styleContext - The MBStyle to which this layer belongs, used as a context for things like resolving sprite and glyph names to full urls.

Returns:

A feature type style from the provided layer, or null if the visibility of that layer is false.

transformInternal

public abstract List<FeatureTypeStyle> transformInternal(MBStyle styleContext)

hashCode

public int hashCode()

Hashcode based on wrapped json.

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Equality based on wrapped json.

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object