Package org.esa.snap.core.jexp

Interface Symbol

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:
$Revision$ $Date$

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    evalB(EvalEnv env)
    Evaluates this symbol to a boolean value.
    double
    evalD(EvalEnv env)
    Evaluates this symbol to a double value.
    int
    evalI(EvalEnv env)
    Evaluates this symbol to an int value.
    String
    evalS(EvalEnv env)
    Evaluates this symbol to a String value.
    String
    getName()
    Gets the symbol's name.
    int
    getRetType()
    Gets the symbol's return type.
    boolean
    isConst()
     

  • Method Details

    • getName

      String getName()
      Gets the symbol's name.
      Returns:
      the name, should never be null

    • getRetType

      int getRetType()
      Gets the symbol's return type.
      Returns:
      the type, should always be one of the TYPE_X constants defined in the Term class.

    • evalB

      boolean evalB(EvalEnv env) throws EvalException
      Evaluates this symbol to a boolean value.
      Parameters:
      env - the application dependant environment.
      Returns:
      a boolean value
      Throws:
      EvalException - if the evaluation fails

    • evalI

      int evalI(EvalEnv env) throws EvalException
      Evaluates this symbol to an int value.
      Parameters:
      env - the application dependant environment.
      Returns:
      an int value
      Throws:
      EvalException - if the evaluation fails

    • evalD

      double evalD(EvalEnv env) throws EvalException
      Evaluates this symbol to a double value.
      Parameters:
      env - the application dependant environment.
      Returns:
      a double value
      Throws:
      EvalException - if the evaluation fails

    • evalS

      String evalS(EvalEnv env) throws EvalException
      Evaluates this symbol to a String value.
      Parameters:
      env - the application dependant environment.
      Returns:
      a double value
      Throws:
      EvalException - if the evaluation fails

    • isConst

      boolean isConst()
      Returns:
      true, if this symbol has a constant value with respect to any EvalEnv, even null.