Package org.esa.snap.core.jexp
Interface Symbol
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- All Known Subinterfaces:
Variable
- All Known Implementing Classes:
RasterDataSymbol
,SingleFlagSymbol
public interface Symbol
Represents a read-only symbol. A symbol can be a named constant or variable. It has a return type an can be evaluated.Within an expression, a reference to a symbol is created if the parser encounters a name and this name can be resolved through the parser's current namespace. The resulting term in this case is an instance of
.Term.Ref
- Version:
- $Revision$ $Date$
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
evalB(EvalEnv env)
Evaluates this symbol to aboolean
value.double
evalD(EvalEnv env)
Evaluates this symbol to adouble
value.int
evalI(EvalEnv env)
Evaluates this symbol to anint
value.String
evalS(EvalEnv env)
Evaluates this symbol to aString
value.String
getName()
Gets the symbol's name.int
getRetType()
Gets the symbol's return type.boolean
isConst()
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Method Detail
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getName
String getName()
Gets the symbol's name.- Returns:
- the name, should never be
null
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getRetType
int getRetType()
Gets the symbol's return type.- Returns:
- the type, should always be one of the
TYPE_
X constants defined in theTerm
class.
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evalB
boolean evalB(EvalEnv env) throws EvalException
Evaluates this symbol to aboolean
value.- Parameters:
env
- the application dependant environment.- Returns:
- a
boolean
value - Throws:
EvalException
- if the evaluation fails
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evalI
int evalI(EvalEnv env) throws EvalException
Evaluates this symbol to anint
value.- Parameters:
env
- the application dependant environment.- Returns:
- an
int
value - Throws:
EvalException
- if the evaluation fails
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evalD
double evalD(EvalEnv env) throws EvalException
Evaluates this symbol to adouble
value.- Parameters:
env
- the application dependant environment.- Returns:
- a
double
value - Throws:
EvalException
- if the evaluation fails
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evalS
String evalS(EvalEnv env) throws EvalException
Evaluates this symbol to aString
value.- Parameters:
env
- the application dependant environment.- Returns:
- a
double
value - Throws:
EvalException
- if the evaluation fails
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isConst
boolean isConst()
- Returns:
true
, if this symbol has a constant value with respect to anyEvalEnv
, evennull
.
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