Application: gvSIG desktop

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

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class ReverseInStrFunction extends AbstractFunction {

    public ReverseInStrFunction() {

        super(

                "String", "REVERSEINSTR", Range.is(2),

                "Returns the index (position) of the last occurrence of a specified substring in a string.",

                "REVERSEINSTR"+"({{string}}, substring)",

                new String[]{

                    "string - String in which to perform the search. ",

                    "substring - String to search"

                },

                "Integer",

                true

        );        

        // Nota: 

        // Habria que poner un formatter. Para REVERSEINSTR(string, substring):

        //   En H2: INSTR(string,substring, -1)

        //   En PostgreSQL: LENGTH(string)-STRPOS(REVERSE(string), substring)

        //   En Oracle: LEN(string)-INSTR(REVERSE(string), substring)

        //   En SQL Server: LEN(string)-CHARINDEX(substring, REVERSE(string))

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

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

        String string = getStr(args, 0);

        String substring = getStr(args, 1);

        if( string == null || substring == null ) {

            return null;

        }

        int n = string.lastIndexOf(substring);

        if( n<0 ) {

            return 0;

        }

        return n+1;

    }

}