Package org.geotools.filter.function
Class StringTemplateFunction
- Object
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- StringTemplateFunction
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- All Implemented Interfaces:
Expression
,Function
public class StringTemplateFunction extends Object implements Function
StringTemplate function, applies a regular expression with capturing groups, and them uses the groups to build a new string based on the provided template.This function expects four expressions in input, the first three of which are mandatory.
- The string to be matched
- A regular expression, possibly using capturing groups
- A template using ${0} for the fully matched string, ${n} for the n-th matching group
- An optional value returned if the regular expresion does not match the input string
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stringTemplate('2002-03-01T13:00:00Z', '\d{4}-\d{2}-\d{2}T(\d{2}):\d{2}:\d{2}', '${1}') will result in
13
(the only matching group returns the hour of the timestamp)stringTemplate('abcd', '\d{4}-\d{2}-\d{2}T(\d{2}):\d{2}:\d{2}', '${1}')
will returnnull
(no match)stringTemplate('abcd', '\d{4}-\d{2}-\d{2}T(\d{2}):\d{2}:\d{2}', '${1}', 'default')
will returndefault
(no match, but there is a default value
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Field Summary
Fields Modifier and Type Field Description static FunctionName
NAME
Make the instance of FunctionName available in a consistent spot.-
Fields inherited from interface Expression
NIL
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Constructor Summary
Constructors Constructor Description StringTemplateFunction()
StringTemplateFunction(List<Expression> parameters, Literal fallback)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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.String
toString()
Creates a String representation of this Function with the function name and the arguments.
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Field Detail
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NAME
public static final FunctionName NAME
Make the instance of FunctionName available in a consistent spot.
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Constructor Detail
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StringTemplateFunction
public StringTemplateFunction()
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StringTemplateFunction
public StringTemplateFunction(List<Expression> parameters, Literal fallback)
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Method Detail
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getName
public String 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
public FunctionName 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
public List<Expression> 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
public Object accept(ExpressionVisitor visitor, Object extraData)
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
public Object evaluate(Object object)
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
public <T> T evaluate(Object object, Class<T> context)
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
public Literal 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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