BlackBerry Math Utilities (Pow & Round)

Question

I'm creating an application from an Excel application that I've used for several years, to calculate mortgage loan details, but I'm having problems with three calculations involving MathUtilities.pow & MathUtilities.round.

Here's my app & the compile error messages that are giving me problems. I've also included my original Excel calculations as reference to what I am trying to calculate using MathUtilities.

Would appreciate some guidance to resolve the problems.

import net.rim.device.api.system.Bitmap;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.util.MathUtilities;
import net.rim.device.api.ui.text.NumericTextFilter;
import net.rim.device.api.ui.text.TextFilter;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.ui.component.BitmapField;
import net.rim.device.api.ui.component.CheckboxField;
import net.rim.device.api.ui.component.EditField;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.Menu;
import net.rim.device.api.ui.component.ObjectChoiceField;
import net.rim.device.api.ui.component.NumericChoiceField;
import net.rim.device.api.ui.component.PasswordEditField;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.component.ButtonField;;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.FontFamily;
import net.rim.device.api.ui.Ui;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.SeparatorField;
import net.rim.device.api.ui.container.MainScreen;

public class LoginSuccessScreen extends MainScreen implements FieldChangeListener {

double a = 0, b = 0, c = 0, d = 0, e = 0, f = 0;       

        EditField mortamt;
        EditField air;
        NumericChoiceField amort;
        NumericChoiceField term;
        ObjectChoiceField freq;
        ButtonField calcButton = null;

         public LoginSuccessScreen(String username) {
                add(new LabelField("Logged in!"));
                add(new LabelField("Username: " + username));

               add(new SeparatorField());

                TextFilter numeric = new NumericTextFilter(NumericTextFilter.ALLOW_DECIMAL);

                mortamt = new EditField("", "");
                LabelField mortamtLabel = new LabelField("Mortgage Amount:    $ ", Field.FIELD_LEFT);
                air = new EditField("", "");
                air.setFilter(numeric);
                LabelField airLabel = new LabelField("Annual Interest Rate:% ", Field.FIELD_LEFT);              
                amort = new NumericChoiceField("",1,35,1,19);
                LabelField amortLabel = new LabelField("Amortization:(Years)", Field.FIELD_LEFT);
                term = new NumericChoiceField("",1,35,1,19);
                LabelField termLabel = new LabelField("Mortgage Term: (Years)", Field.FIELD_LEFT);
                freq= new ObjectChoiceField("", new String[] {"Weekly", "Bi-Weekly","Semi-Monthly", "Monthly"});
                LabelField freqLabel = new LabelField("Payment Frequency:", Field.FIELD_LEFT);


                add(new SeparatorField());

                add(new SeparatorField());
                GridFieldManager gridFieldManager = new GridFieldManager(2, 0);
                gridFieldManager.add(mortamtLabel);
                gridFieldManager.add(mortamt);
                gridFieldManager.add(airLabel);
                gridFieldManager.add(air);
                gridFieldManager.add(amortLabel);
                gridFieldManager.add(amort);
                gridFieldManager.add(termLabel);
                gridFieldManager.add(term);
                gridFieldManager.add(freqLabel);
                gridFieldManager.add(freq);

                add(gridFieldManager);

                calcButton = new ButtonField("Calculate Amounts:", ButtonField.CONSUME_CLICK);
                calcButton.setChangeListener(this);
                add(calcButton);  

            }
                public void fieldChanged(Field field, int context) {
                if (calcButton == field) {         
        }      

                int a = Integer.parseInt(mortamt.getText());
                add(new LabelField("Principal Amount: $" + a)); 

                int b = Integer.parseInt(amort.getChoice(amort.getSelectedIndex()).toString());
                add(new LabelField("Period to Amortization " +b * 12 + " months"));

                double c = Float.parseFloat(air.getText()) / 100.;
                add(new LabelField("AIR: %" + c));

                add(new LabelField("Monthly Interest Factor %" + d));
                double d = MathUtilities.pow(MathUtilities.pow((1+(c/2)), 2), 1/12) - 1;

                add(new LabelField("EAR: "  +e ));               
                double e =(float)MathUtilities.round((MathUtilities.pow(1+d,12)-1) * 10000 ) / 10000;

                add(new LabelField("Monthly Payment: $" + f));
                double f = ((a*d)/(MathUtilities.pow(1-(1+d)) -c));

                add(new SeparatorField());   
             }   
            }

ERROR MESSAGES:

Building UiFun
C:\Research In Motion\BlackBerry JDE 4.5.0\bin\rapc.exe  -quiet import="..\Research In Motion\BlackBerry JDE 4.5.0\lib\net_rim_api.jar" codename=UiFun UiFun.rapc warnkey=0x52424200;0x52525400;0x52435200 "C:\Mortgage Calculator\res\apress_logo.png" "C:\Mortgage Calculator\res\login_arrow.png" "C:\Mortgage Calculator\res\login_icon.png" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\CustomButtonField.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\CustomDialog.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\CustomLabelField.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\CustomObjectChoiceField.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\GridFieldManager.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\UiFunApplication.java" "C:\Mortgage Calculator\src\com\beginningblackberry\uifun\UiFunMainScreen.java"
C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java:102: cannot find symbol
symbol  : method pow(double,int)
location: class net.rim.device.api.util.MathUtilities
                double d = MathUtilities.pow(MathUtilities.pow((1+(c/2)), 2), 1/12) - 1;
                                                          ^
C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java:105: cannot find symbol
symbol  : method pow(double,int)
location: class net.rim.device.api.util.MathUtilities
                double e =(float)MathUtilities.round((MathUtilities.pow(1+d,12)-1) * 10000 ) / 10000;
                                                                   ^
C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java:105: cannot find symbol
symbol  : method round(int)
location: class net.rim.device.api.util.MathUtilities
                double e =(float)MathUtilities.round((MathUtilities.pow(1+d,12)-1) * 10000 ) / 10000;
                                              ^
C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java:105: inconvertible types
found   : net.rim.device.api.util.MathUtilities.round
required: float
                double e =(float)MathUtilities.round((MathUtilities.pow(1+d,12)-1) * 10000 ) / 10000;
                                                    ^
C:\Mortgage Calculator\src\com\beginningblackberry\uifun\LoginSuccessScreen.java:108: cannot find symbol
symbol  : method pow(double)
location: class net.rim.device.api.util.MathUtilities
                double f = ((a*d)/(MathUtilities.pow(1-(1+d)) -c));
                                                ^
5 errors
Error!: Error: java compiler failed: javac -source 1.3 -target 1.1 -g -O -d C:\Users\ALEXMC~1\AppData\Local\Temp\rapc_1c2f4822.dir -boot ...
Error while building project

The original Excel calculations are:

((1+(air/2)^)^(1/12)-1

(

Answer 1

Those methods were added to MathUtilities in the 4.6 API, so you'll need to compile for that version or later in order to use them.

If you do need to compile for 4.3 or 4.5, you'll need to find a J2ME implementation of those functions elsewhere.