Class RecodeFunction
- All Implemented Interfaces:
Expression
,Function
The Recode function provides a lookup table facility (think HashTable) where both keys and values can be any
Expression
. The first parameter to the function specifies the source of the value to lookup, e.g. the name of
a feature property as a Literal
. The remaining parameters define the lookup table as key:value pairs. Thus
there should be an odd number of parameters in total: the lookup value parameter plus the set of key value pairs.
Where the lookup involves String
values, comparisons are done case-insensitively.
If the lookup value does not match any of the keys defined this function returns null
.
- Author:
- Johann Sorel (Geomatys), Michael Bedward
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final FunctionName
Make the instance of FunctionName available in a consistent spot.Fields inherited from interface Expression
NIL
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionaccept
(ExpressionVisitor visitor, Object extraData) Accepts a visitor.boolean
Evaluates the given expression based on the content of the given object.<T> T
Evaluates the given expressoin based on the content of the given object and the context type.The value of the fallbackValue attribute is used as a default value, if the SE implementation does not support the function.Access to the FunctionName description as used in a FilterCapabilities document.getName()
Returns the name of the function to be called.Returns the list subexpressions that will be evaluated to provide the parameters to the function.int
hashCode()
toString()
Creates a String representation of this Function with the function name and the arguments.
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Field Details
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NAME
Make the instance of FunctionName available in a consistent spot.
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Constructor Details
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RecodeFunction
public RecodeFunction() -
RecodeFunction
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Method Details
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getName
Description copied from interface:Function
Returns the name of the function to be called. For example, this might be "cos
" 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.
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getFunctionName
Description copied from interface:Function
Access to the FunctionName description as used in a FilterCapabilities document.- Specified by:
getFunctionName
in interfaceFunction
- Returns:
- FunctionName description, if available.
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getParameters
Description copied from interface:Function
Returns the list subexpressions that will be evaluated to provide the parameters to the function.- Specified by:
getParameters
in interfaceFunction
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accept
Description copied from interface:Expression
Accepts a visitor. Subclasses must implement with a method whose content is the following:return visitor.visit(this, extraData);
- Specified by:
accept
in interfaceExpression
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evaluate
Description copied from interface:Expression
Evaluates the given expression based on the content of the given object.- Specified by:
evaluate
in interfaceExpression
- Returns:
- computed value
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evaluate
Description copied from interface:Expression
Evaluates the given expressoin based on the content of the given object and the context type.The
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 ofcontext
. Therefore to be safe calling code should do a null check on the return value of this method, and callExpression.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 returnnull
.- Specified by:
evaluate
in interfaceExpression
- Type Parameters:
T
- The type of the returned object.- Parameters:
object
- The object to evaluate the expression against.context
- The type of the resulting value of the expression.- Returns:
- Evaluates the given expression based on the content of the given object an an instance of
context
.
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getFallbackValue
Description copied from interface:Function
The value of the fallbackValue attribute is used as a default value, if the SE implementation does not support the function. If the implementation supports the function, then the result value is determined by executing the function.- Specified by:
getFallbackValue
in interfaceFunction
- Returns:
- Optional literal to use if an implementation for this function is not available.
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toString
Creates a String representation of this Function with the function name and the arguments. -
equals
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hashCode
public int hashCode()
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