Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.programming;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import static org.gvsig.expressionevaluator.ExpressionBuilder.FUNCTION_$CONSTANT;

import static org.gvsig.expressionevaluator.ExpressionBuilder.FUNCTION_$IDENTIFIER;

public class $IdentifierFunction extends AbstractFunction {

    public $IdentifierFunction() {

        super(Function.GROUP_PROGRAMMING, 

                FUNCTION_$IDENTIFIER, 

            Range.is(1),

            "Evaluate the parameter as a string and return the value of the variable referred by this string.\n" +

                "This function is used to mark that the result of evaluate the parameter must be "+

                    "converted to a variable identifier when generating the SQL expression. ",

            FUNCTION_$IDENTIFIER+"({{expression}})",

            null,

            "Object",

            false

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return false;

    }    

    @Override

    public Object call(Interpreter interpreter, final Object[] args) throws Exception {

        String identifier = this.getStr(args, 0);

        return interpreter.getSymbolTable().value(identifier);        

    }

}