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.Formatter;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.PrettyFormatter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dataTypes.DataTypes;

import org.gvsig.tools.dataTypes.Coercion;

public class CaseFunction extends AbstractFunction {

    public static final String NAME = "CASE";

    public CaseFunction() {

        super(Function.GROUP_PROGRAMMING, 

                NAME, 

                Range.between(2, Integer.MAX_VALUE),

                "",

                "CASE\n  WHEN {{condition}} THEN PASS\n  ELSE PASS\nEND CASE\n",

                null,

                "Object",

                true

        );

    }

    @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 {

        // CASE(cond1, cond2, cond3,... condN, expr1, expr2, expr3... exprN, exprElse)

        //      0      1      2                3      4      5               6

        Coercion toBoolean = ToolsLocator.getDataTypesManager().getCoercion(DataTypes.BOOLEAN);

        int count;

        int firstValue;

        int elseValue;

        if( (args.size() % 2) == 0) {

            count = args.size() / 2;

            firstValue = count;

            elseValue = -1;

        } else {

            count = (args.size()-1) / 2;

            firstValue = count;

            elseValue = args.size()-1;

        }

        boolean needElse = true;

        Object value = null;

        for( int n=0; n<count; n++ ) {

            Object condition_o = getObject(interpreter, args, n);

            Boolean condition = (Boolean) toBoolean.coerce(condition_o);

            if( condition!=null && condition==true ) {

                needElse = false;

                value = getObject(interpreter, args, n+firstValue);

                return value;

            }

        }

        if( needElse && elseValue>0 ) {

            value = getObject(interpreter, args, elseValue);        

        }

        return value;

    }

    @Override

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

        PrettyFormatter builder = PrettyFormatter.get(formatter);

        try {

            builder.push();

            int count;

            int firstValue;

            int elseValue;

            Code codeElse = null;

            if( (args.size() % 2) == 0) {

                count = args.size() / 2;

                firstValue = count;

                elseValue = -1;

            } else {

                count = (args.size()-1) / 2;

                firstValue = count;

                elseValue = args.size()-1;

                codeElse = (elseValue>0)? args.get(elseValue):null;

            }

            builder.append("CASE ");

            builder.indent();            

            for( int n=0; n<count; n++ ) {

                builder.nl();

                builder.append("WHEN ");

                builder.append(args.get(n).toString(formatter));

                builder.append(" THEN ");

                builder.indent();

                builder.nl();

                Code codeBody = args.get(n+firstValue);

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

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

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

                        builder.nl();

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

                        builder.append("; ");

                    }

                } else {

                    builder.nl();

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

                    builder.append("; ");

                }                   

                builder.unindent();

            }

            if( codeElse!=null) {

                builder.nl();

                builder.append("ELSE ");

                builder.indent();

                builder.nl();

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

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

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

                        builder.nl();

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

                        builder.append("; ");

                    }

                } else {

                    builder.nl();

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

                    builder.append("; ");

                }                   

                builder.unindent();

            }

            builder.unindent();

            builder.nl();

            builder.append("END");

            return builder.build();

        } finally {

            builder.pop();

        }

    }

}