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@XmlElement(value="Rule") @UML(identifier="PF_PortrayalRule", specification=ISO_19117) public interface Rule
A rule consists of two important parts: a filter and a list of symbols. When it is time to draw a given feature, the rendering engine examines each rule in the FeatureStyle, first checking its Filter (or ElseFilter). If the Filter passes, then every Symbolizer for that rule is applied to the given feature.
Method Summary | |
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Object |
accept(StyleVisitor visitor,
Object extraData)
calls the visit method of a StyleVisitor |
Description |
getDescription()
Returns the description of this rule. |
Filter |
getFilter()
Returns the filter that will limit the features for which this Rule will
fire. |
GraphicLegend |
getLegend()
Returns a small Graphic that could be used by the rendering engine to draw a legend window. |
double |
getMaxScaleDenominator()
Returns the maximum value (exclusive) in the denominator of the current map scale at which this Rule will fire. |
double |
getMinScaleDenominator()
Returns the minimum value (inclusive) in the denominator of the current map scale at which this Rule will fire. |
String |
getName()
Returns a name for this rule. |
OnLineResource |
getOnlineResource()
It is common to have a style coming from a external xml file, this method provide a way to get the original source if there is one. |
boolean |
isElseFilter()
Returns true if this Rule is to fire only if no other rules in the containing
style have fired yet. |
List<? extends Symbolizer> |
symbolizers()
This method returns the list of Symbolizer objects contained by this Rule . |
Method Detail |
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@XmlElement(value="Name") @UML(identifier="ruleName", obligation=MANDATORY, specification=ISO_19117) String getName()
@XmlElement(value="Description") @UML(identifier="description", obligation=OPTIONAL, specification=ISO_19117) Description getDescription()
@XmlElement(value="LegendGraphic") GraphicLegend getLegend()
A nice user interface may want to present the user with a legend that
indicates how features of a given type are being portrayed. Through its
LegendGraphic
property, a Rule
may provide a custom picture
to be used in such a legend window.
@XmlElement(value="Filter") @UML(identifier="queryStatement", obligation=MANDATORY, specification=ISO_19117) Filter getFilter()
Rule
will
fire. This can only be non-null if isElseFilter()
returns false. If this
value is null and isElseFilter
is false, this means that this Rule
should fire for all features.
@XmlElement(value="ElseFilter") boolean isElseFilter()
Rule
is to fire only if no other rules in the containing
style have fired yet. If this is true, then the filter must be Filter.EXCLUDES.
@XmlElement(value="MinScaleDenominator") double getMinScaleDenominator()
Rule
will fire.
If, for example, the MinScaleDenominator
were 10000, then this rule
would only fire at scales of 1:X where X is greater than 10000.
A value of zero indicates that there is no minimum.
@XmlElement(value="MaxScaleDenominator") double getMaxScaleDenominator()
Rule
will fire.
If, for example, the MaxScaleDenominator
were 98765, then this rule
would only fire at scales of 1:X where X is less than 98765.
A value of Double.POSITIVE_INFINITY
indicates that there is no maximum.
@XmlElement(value="Symbolizer") @UML(identifier="portrayAction", obligation=MANDATORY, specification=ISO_19117) List<? extends Symbolizer> symbolizers()
Rule
.
We use a list of extends Symbolizer> to enable the possibility
for an implementation to return a special type of Symbolizer.
This doesnt mean a Rule must return a list of PointSymbolizer or
TextSymbolizer only, no. The purpose of this if to offer the solution
to return different implementations like MutableSymbolizer or RichSymbolizer
and then avoid redundant cast in the code.
If you dont intend to use a special interface you can override this method
by : List
OnLineResource getOnlineResource()
@Extension Object accept(StyleVisitor visitor, Object extraData)
visitor
- the style visitor
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