Application: gvSIG desktop

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

import java.util.Objects;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Codes;

import org.gvsig.expressionevaluator.Formatter;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.PrettyFormatter;

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

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

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class WhileFunction extends AbstractFunction {

    public static final String NAME = "WHILE";

    public WhileFunction() {

        super(Function.GROUP_PROGRAMMING, 

                NAME, 

                Range.is(2),

                "The while() function evaluate expression while the condition is true.",

                "WHILE {{condition}} BEGIN\n  PASS;\nEND WHILE\n",

                null,

                "Object",

                false

        );

    }

    @Override

    public boolean isHidden() {

      return true;

    }

    @Override

    public boolean useArgumentsInsteadObjects() {

        return true;

    }

    @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 boolean allowConstantFolding() {

        return false;

    }    

    @Override

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

        Object body = null;

        int argn = 0;

        boolean condition = getBoolean(interpreter, args, 0);

        while( condition ) {

            try {

                body = getObject(interpreter, args, 1);

            } 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 while function calling arg "+ argn + ", "+ stmt, ex);

                throw ex;

            }

            condition = getBoolean(interpreter, args, 0);

            argn++;

        }

        return body;

    }

    @Override

    public String toString(Codes args, Formatter<Code> formatter) {

        Code codeCondition = args.get(0);

        Code codeLoopBody = args.get(1);

        PrettyFormatter builder = PrettyFormatter.get(formatter);

        try {

            builder.push();

            builder.append("WHILE ");

            builder.append(codeCondition.toString(formatter));

            builder.append(" LOOP ");

            builder.indent();

            builder.nl();

            if( Code.isFunction(codeLoopBody,"BLOCK") ) {

                Code.Callable block = (Code.Callable)codeLoopBody;

                for (Code parameter : block.parameters()) {

                    builder.nl();

                    builder.append(parameter.toString(formatter));

                    builder.append("; ");

                }

            } else {

                builder.nl();

                builder.append(codeLoopBody.toString(formatter));

                builder.append(" ");

            }            

            builder.unindent();

            builder.nl();

            builder.append("END LOOP ");

            return builder.build();

        } finally {

            builder.pop();

        }

    }

}