Application: gvSIG desktop

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

import java.util.Objects;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Codes;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.expressionevaluator.ExpressionRuntimeException;

import org.gvsig.expressionevaluator.MutableSymbolTable;

import org.gvsig.expressionevaluator.impl.function.programming.BreakFunction.BreakException;

import org.gvsig.expressionevaluator.impl.function.programming.ReturnFunction.ReturnException;

public class ForEachFunction extends AbstractFunction {

    public static final String NAME = "FOREACH";

    public ForEachFunction() {

        super(Function.GROUP_PROGRAMMING, 

                NAME, 

                Range.is(3),

                "The foreach() function evaluate body for every element of the iterable.",

                "FOR n IN {{expression}}\n  BEGIN\n  PASS;\nEND FOR\n",

                null,

                "Object",

                false

        );

    }

    @Override

    public boolean isHidden() {

      return true;

    }

    @Override

    public boolean useArgumentsInsteadObjects() {

        return true;

    }

    @Override

    public boolean allowConstantFolding() {

        return false;

    }

    @Override

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

        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.

    }

    @Override

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

        if ( getObject(interpreter, args, 1)==null) {

            return null;

        }

        if( !(interpreter.getSymbolTable() instanceof MutableSymbolTable) ) {

            throw new ExpressionRuntimeException("The use of forech loops require a mutable symbol table.");

        }

        MutableSymbolTable symbolTable = (MutableSymbolTable) interpreter.getSymbolTable();

        Object body = null;

        String varname = getObject(interpreter, args, 0).toString();

        int argn = 1;

        Iterable iterable = (Iterable) getObject(interpreter, args, 1);

        for (Object value : iterable) {

            symbolTable.setVar(varname, value);

            try {

                Object x = getObject(interpreter, args, 2);

                body = x;

            } catch(BreakException ex) {

                break;

            } catch(ReturnException ex) {

                throw ex;

            } catch(Exception ex) {

                String stmt = "unknown";

                try {

                    stmt = Objects.toString(args);

                } catch(Exception ex2) {

                }

                LOGGER.warn("Error in foreach function calling arg "+ argn + ", "+ stmt, ex);

                throw ex;

            }

            argn++;

        }

        return body;

    }

}