public class PolygonLabelFunction extends Object implements Function
NIL| Constructor and Description |
|---|
PolygonLabelFunction(List<Expression> parameters,
Literal fallback) |
| Modifier and Type | Method and Description |
|---|---|
Object |
accept(ExpressionVisitor visitor,
Object extraData)
Accepts a visitor.
|
Object |
evaluate(Object object)
Evaluates the given expression based on the content of the given object.
|
<T> T |
evaluate(Object object,
Class<T> context)
Evaluates the given expressoin based on the content of the given object and the context type.
|
Literal |
getFallbackValue()
The value of the fallbackValue attribute is used as a default value, if the SE implementation
does not support the function.
|
FunctionName |
getFunctionName()
Access to the FunctionName description as used in a FilterCapabilities document.
|
String |
getName()
Returns the name of the function to be called.
|
List<Expression> |
getParameters()
Returns the list subexpressions that will be evaluated to provide the parameters to the
function.
|
public PolygonLabelFunction(List<Expression> parameters, Literal fallback)
public Object evaluate(Object object)
Expressionevaluate in interface Expressionpublic <T> T evaluate(Object object, Class<T> context)
ExpressionThe context parameter is used to control the type of the result of the expression.
A particular expression may not be able to evaluate to an instance of context.
Therefore to be safe calling code should do a null check on the return value of this method,
and call Expression.evaluate(Object) if neccessary. Example:
Object input = ...;
String result = expression.evaluate( input, String.class );
if ( result == null ) {
result = expression.evalute( input ).toString();
}
...
Implementations that can not return a result as an instance of context should
return null.
evaluate in interface ExpressionT - The type of the returned object.object - The object to evaluate the expression against.context - The type of the resulting value of the expression.context.public Object accept(ExpressionVisitor visitor, Object extraData)
Expressionreturn visitor.visit(this, extraData);
accept in interface Expressionpublic String getName()
Functioncos" or
"atan2".
You can use this name to look up the number of required parameters in a FilterCapabilities data structure. For the specific meaning of the required parameters you will need to consult the documentation.
public FunctionName getFunctionName()
FunctiongetFunctionName in interface Functionpublic List<Expression> getParameters()
FunctiongetParameters in interface Functionpublic Literal getFallbackValue()
FunctiongetFallbackValue in interface FunctionCopyright © 1996–2019 Geotools. All rights reserved.