Application: gvSIG desktop

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

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Codes;

import org.gvsig.expressionevaluator.ExpressionBuilder;

import org.gvsig.expressionevaluator.Formatter;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.PrettyFormatter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class IFFunction extends AbstractFunction {

    public IFFunction() {

        super(Function.GROUP_BOOLEAN, 

                ExpressionBuilder.FUNCTION_IF, 

                Range.between(2,3),

                ExpressionBuilder.FUNCTION_IF+"() function tests a specified numeric expression and returns one of two values, based on whether the expression tested was true or false.",

                "IF {{condition}} THEN\n  PASS\nELSE\n  PASS;\nEND IF\n",

                null,

                "Object",

                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."); 

    }

    @Override

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

        Object value;

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

        if( condition ) {

            value = getObject(interpreter, args, 1);

        } else {

            if( args.size()>2 && args.get(2)!=null ) {

                value = getObject(interpreter, args, 2);

            } else {

                value = null;

            }

        }

        return value;

    }

    @Override

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

        Code codeCondition = args.get(0);

        Code codeIfTrue = args.get(1);

        Code codeIfFalse = (args.size() > 2)? args.get(2):null;

        PrettyFormatter builder = PrettyFormatter.get(formatter);

        try {

            builder.push();

            builder.append("IF ");

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

            builder.append(" THEN ");

            builder.indent();

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

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

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

                    builder.nl();

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

                    builder.append("; ");

                }

            } else {

                builder.nl();

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

                builder.append("; ");

            }            

            builder.unindent();

            if( codeIfFalse!=null ) {

                builder.nl();

                builder.append("ELSE ");

                builder.indent();

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

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

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

                        builder.nl();

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

                        builder.append("; ");

                    }

                } else {

                    builder.nl();

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

                    builder.append("; ");

                }            

            }

            builder.nl();

            builder.append("END IF");

            return builder.build();

        } finally {

            builder.pop();

        }

    }

}