Develop Reference

Can't get the subclass to inherit or override from the superclass

I'm positive I covered the basics. I put #Override before overriding methods. I made sure to include 'extends Super' on the line of the class. I can't override the constructor either. I passed the right amount of variables of the correct type and it gives me an error message saying 'actual and formal argument lists differ in length.' Along with errors not reading the static variables from the TuitionConstants class.
// This is the super class
public abstract class Student implements Comparable<Student> {
private int mCredits;
private String mFirstName;
private String mId;
private String mLastName;
private double mTuition;
public Student(String pId, String pFirstName, String pLastName) {
mId = pId;
mFirstName = pFirstName;
mLastName = pLastName;
}
public abstract void calcTuition();
#Override
public int compareTo(Student pStudent) {
return getId().compareTo(pStudent.getId());
}
public int getCredits() {
return mCredits;
}
public String getFirstName() {
return mFirstName;
}
public String getId() {
return mId;
}
public String getLastName() {
return mLastName;
}
public double getTuition() {
return mTuition;
}
public void setCredits(int pCredits) {
mCredits = pCredits;
}
public void setFirstName(String pFirstName) {
mFirstName = pFirstName;
}
public void setId(String pId) {
mId = pId;
}
public void setlastName(String pLastName) {
mLastName = pLastName;
}
protected void setTuition(double pTuition) {
mTuition = pTuition;
}
}
import p02.Student;
import p02.TuitionConstants;
public class OnCampusStudent extends Student {
public static final int RESIDENT = 1;
public static final int NON_RESIDENT = 2;
private int mResident;
private double mProgramFee;
//Error on this constructor. Says 'actual and formal argument lists differ in length
public OnCampusStudent(String pId, String pFirstName, String pLastName) {
super(pId, pFirstName, pLastName);
}
// Errors on this method. On #Override line:"method does not override or implement a method
// from a supertype. Also on the lines that call getCredits(), it says "cannot find symbol,"
// but it's a method from the superclass. Same "cannot find symbol" error on the lines that call
// the static variables from the TuitionConstants class.
#Override
public void calcTuition() {
double t;
if (getResidency() == RESIDENT) {
t = TuitionConstants.ONCAMP_RES_BASE;
} else {
t = TuitionConstants.ONCAMP_NONRES_BASE;
}
t = t + getProgramFee();
if (getCredits() > TuitionConstants.ONCAMP_MAX_CREDITS) {
t = t + (getCredits() - TuitionConstants.ONCAMP.MAX.CREDITS) * TuitionConstants.ONCAMP_ADD_CREDITS;
}
setTuition(t);
}
}
// Here is the TuitionConstants Class.
public class TuitionConstants {
public static final int ONCAMP_ADD_CREDITS = 475;
public static final int ONCAMP_MAX_CREDITS = 18;
public static final int ONCAMP_NONRES_BASE = 14875;
public static final int ONCAMP_RES_BASE = 7575;
public static final int ONLINE_CREDIT_RATE = 950;
public static final int ONLINE_TECH_FEE = 75;
}

Boolean wrong output

my code:
public class Kuh {
private String name;
private boolean istSatt;
public Kuh(String name, boolean istSatt) {
}
public double gibMilch() {
if (istSatt == true) {
System.out.println(10.0);
return 10.0;
} else {
System.out.println(3.0);
return 3.0;
}
}
public void grasen() {
istSatt = true;
}
public static void main(String[] args) {
Kuh Frida = new Kuh("Frida", true);
Frida.gibMilch();
Frida.grasen();
Frida.gibMilch();
}
}
My problem: I set "istSatt" of the object "Frida" to "true" at creation. So when using the method "gibMilch", it should put out "10". Despite that, it puts out "3", like the boolean would be false, even tho I set it to true. It only puts out "10" after using "grasen".
What did I do wrong?

You are not assigning the constructor parameters to the fields.
public Kuh(String name, boolean istSatt) {
this.name = name;
this.istSatt = istSatt;
}

You need to set your class variable values in your constructor:
public Kuh(String name, boolean istSatt) {
this.name = name;
this.istSatt = istSatt;
}
Here this refers to the class you are instantiating.

Try this instead, as you did not seem to assign to anything on the call to Kuh Frida = new Kuh("Frida", true);
i.e.
public class Kuh {
private String name;
private boolean istSatt;
public Kuh(String name, boolean istSatt) {
this.istSatt=istSatt;
this.name=name;
}
public double gibMilch() {
if (istSatt) {
System.out.println(10.0);
return 10.0;
} else {
System.out.println(3.0);
return 3.0;
}
}
public void grasen() {
istSatt = true;
}
public static void main(String[] args) {
Kuh Frida = new Kuh("Frida", true);
Frida.gibMilch();
Frida.grasen();
Frida.gibMilch();
}
}

"Color cannot be resolved to a type"?

import java.awp.*;
public class Reindeer
{
private String name;
private boolean canFly;
private Color noseColor;
private int antlers;
public Reindeer()
{
}
public Reindeer(String nameIn, boolean canFlyIn, Color noseColorIn, int antlersIn)
{
name = nameIn;
canFly = canFlyIn;
noseColor = noseColorIn;
antlers = antlersIn;
}
public String getName()
{
return name;
}
public boolean getCanFly()
{
return canFly;
}
public Color getNoseColor()
{
return noseColor;
}
public int getAntlers()
{
return antlers;
}
public void setCanFly(boolean canFlyIn)
{
canFly = canFlyIn;
}
public void setNoseColor(Color noseColorIn)
{
noseColor = noseColorIn;
}
public void setAntlers(int antlersIn)
{
antlers = antlersIn;
}
public String toString()
{
return "The Reindeer's name is " + name + " and it has a " + noseColor + " nose.";
}
}
Unsure of what to do here, would be great if I had some help. I know I have to import something but I had forgotten what it is and I believe it is something along the lines of 'import java.awp.*;' Thanks!

I think that's a typo. The java.* top-level packages are restricted, so there are only so many and they are all known. awp is probably supposed to be awt.

What is the correct way to do this?

I know this must be a fundamental design problem because I clearly can't do this. I want to call the ownGrokk, ownTyce, etc methods from another class depending on the value of the integer assigned to OwnedSpirits(int). This in turn fills arrays.
The problem is, I do this multiple times, and doing it from another class it seems like I have to make a new object every time to pass the new int argument, and doing so resets the value of spiritInstance. And, since that resets to zero, the arrays don't fill properly. I try to print out my array values later and I get an "ArrayIndexOutOfBoundsException".
public class OwnedSpirits {
private int spiritTypeInt = 0;
public static int spiritInstance=0;
public static int[] spiritarray = new int[9];
public static String[] spiritName = new String[9];
public static int[] party = new int[3];
public OwnedSpirits(int spiritcall){
if(spiritcall == 1){
ownGrokk();
}
if(spiritcall == 2){
ownRisp();
}
if(spiritcall == 3){
ownTyce();
}
if(spiritcall == 4){
ownDaem();
}
if(spiritcall == 5){
ownCeleste();
}
}
private void ownGrokk(){
spiritName[spiritInstance] = "Grokk";
spiritInstance++;
}
private void ownRisp(){
spiritName[spiritInstance] = "Risp";
spiritInstance++;
}
private void ownDaem(){
spiritName[spiritInstance] = "Daem";
spiritInstance++;
}
private void ownCeleste(){
spiritName[spiritInstance] = "Celeste";
spiritInstance++;
}
private void ownTyce(){
spiritName[spiritInstance] = "Tyce";
spiritInstance++;
}
and this code is in another class, where it attempts to call the methods to fill the array
buttonConfirm.addListener(new ClickListener(){
#Override
public void clicked(InputEvent event, float x, float y) {
if(xcounter==3){
for(x=0; x<3; x++){
if(setdaemtrue == true){
new OwnedSpirits(4);
}
if(setrisptrue == true){
new OwnedSpirits(2);
}
if(setcelestetrue == true){
new OwnedSpirits(5);
}
if(settycetrue == true){
new OwnedSpirits(3);
}
if(setgrokktrue == true){
new OwnedSpirits(1);
}
}
}
}
});
and finally in yet another class:
System.arraycopy(OwnedSpirits.spiritName, 0, partylist, 0, 3);
#Override
public void show() {
System.out.println(partylist[0]);
System.out.println(partylist[1]);
System.out.println(partylist[2]);
spiritlist.setItems(partylist);
table.add(spiritlist);
table.setFillParent(true);
stage.addActor(table);
}
If the last part is confusing, it's because I am using libgdx. the print statements are there just to try to figure out why my list was having an error

I can show you what I would do to handle Spirits, and Parties.
The Spirit class, contains name and current party its assigned to:
package com.stackoverflow.spirit;
public class Spirit {
private String name;
private Party party;
private SpiritType type;
private static int id = 0;
public static enum SpiritType {
Grokk, Risp, Tyce, Daem, Celeste
};
public Spirit(String name, SpiritType type) {
create(name, type);
}
public Spirit(SpiritType type) {
create(null, type);
}
// This is to handle Java inexistance of default parameter values.
private void create(String name, SpiritType type)
{
Spirit.id++;
this.name = (name == null) ? (type.name() + " " + id) : name;
this.type = type;
}
public String getName() {
return name;
}
public Party getParty() {
return party;
}
public SpiritType getType() {
return type;
}
/**
* Used internally by #see Party
* #param party the party this Spirit belongs
*/
public void setParty(Party party) {
this.party = party;
}
public void setName(String name) {
this.name = name;
}
#Override
public String toString()
{
return this.name;
}
}
Finally the Party class, contains a set of Spirits, you can add and remove Spirits from the party.
package com.stackoverflow.spirit;
import java.util.HashSet;
public class Party {
private HashSet<Spirit> spirits = new HashSet<Spirit>();
private static int id = 0;
private String name = "Party " + Party.id++;;
public Party() {
}
public Party(String name) {
this.name = name;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void add(Spirit spirit) {
if (!spirits.contains(spirit)) {
spirits.add(spirit);
if (spirit.getParty() != null) {
//Remove from previous party to update the other party set
spirit.getParty().remove(spirit);
}
spirit.setParty(this);
} else {
// throw new SpiritAlreadyOnParty();
}
}
public void remove(Spirit spirit)
{
if (spirits.contains(spirit))
{
spirit.setParty(null); // You could create a default empty party for "Nature/Neutral" Spirits perhaps :)
spirits.remove(spirit);
}
else {
//throw new SpiritNotInParty();
}
}
public boolean isOnParty(Spirit spirit) {
return spirits.contains(spirit);
}
public ArrayList<Spirit> getSpirits()
{
return new ArrayList<Spirit>(spirits);
}
public int getPartySize() {
return spirits.size();
}
public String getPartyInfo()
{
StringBuilder builder = new StringBuilder();
builder.append("Party:" + this.name + " Size:" + this.spirits.size() + "\n");
for (Spirit s : spirits)
{
builder.append(s.getName() + "\n");
}
return builder.toString();
}
#Override
public String toString()
{
return this.name;
}
}
Here I use the Spirit and Party classes, you could add more functionality, like properties for party strength, magic buffs on the party, etc:
package com.stackoverflow.spirit;
import com.stackoverflow.spirit.Spirit.SpiritType;
public class Main {
public static void main(String[] args) throws java.lang.Exception {
Party griffindor = new Party("Griffindor"), slytherin = new Party(
"Slytherin");
// You can also do for (SpiritType type : SpiritType.values() then
// type.ordinal()
for (int i = 0; i < SpiritType.values().length; i++) {
griffindor.add(new Spirit(SpiritType.values()[i]));
slytherin.add(new Spirit(SpiritType.values()[i]));
}
Spirit mySpirit = new Spirit("NotAHPFan", SpiritType.Celeste);
slytherin.add(mySpirit);
System.out.println("Name of party:" + mySpirit.getParty().getName());
System.out.println("Is on griffindor?:"
+ griffindor.isOnParty(mySpirit));
// What now?
griffindor.add(mySpirit);
System.out.println("Is " + mySpirit.getName() + " on "
+ slytherin.getName() + "?:" + slytherin.isOnParty(mySpirit));
System.out.println(mySpirit.getName() + " is now on "
+ mySpirit.getParty() + "\n");
System.out.println(griffindor.getPartyInfo());
System.out.println(slytherin.getPartyInfo());
}
}
P.D: I'm not a HP fan.

Travesring through an object in java

I have a method that return an object of a class.The object sets the properties of class and returns.
I have to traverse the object and get the value of the properties which the object has set before.
I tried to use for-each loop,iterator but failed to traverse.
Can someone please help me to get through this.Thanks in advance.
code:
public class ConsumerTool {
public MessageBean getMessages() {
MessageBean msgBean = new MessageBean();
msgBean.setAtmId(atmId.trim());
msgBean.setEventText(eventText.trim());
msgBean.setEventNumber(eventNumber.trim());
msgBean.setSeverity(severity.trim());
msgBean.setSubsystemID(subsystemID.trim());
msgBean.setUniqueEventID(uniqueEventID.trim());
msgBean.setTaskID(taskID.trim());
msgBean.setGenerator(generator.trim());
msgBean.setGeneratorBuildVsn(generatorBuildVsn.trim());
msgBean.setDateTime(dateTime.trim());
this.msgBean = msgBean;
return msgBean;
}
}
JavaBean class:
public class MessageBean implements java.io.Serializable {
public String dateTime;
public String severity;
public String eventText;
public String eventNumber;
public String generator;
public String generatorBuildVsn;
public String atmId;
public String uniqueEventID;
public String subsystemID;
public String taskID;
//System.out.println("dateTime2222222"+dateTime);
public String getAtmId() {
return this.atmId;
}
public void setAtmId(String n) {
this.atmId = n;
}
public String getDateTime() {
return this.dateTime;
}
public void setDateTime(String n) {
this.dateTime = n.trim();
}
public String getEventNumber() {
return this.eventNumber;
}
public void setEventNumber(String n) {
this.eventNumber = n;
}
public String getEventText() {
return this.eventText;
}
public void setEventText(String n) {
this.eventText = n;
}
public String getGenerator() {
return this.generator;
}
public void setGenerator(String n) {
this.generator = n;
}
public String getGeneratorBuildVsn() {
return this.generatorBuildVsn;
}
public void setGeneratorBuildVsn(String n) {
this.generatorBuildVsn = n;
}
public String getSeverity() {
return this.severity;
}
public void setSeverity(String n) {
this.severity = n;
}
public String getSubsystemID() {
return this.subsystemID;
}
public void setSubsystemID(String n) {
this.subsystemID = n;
}
public String getTaskID() {
return this.taskID;
}
public void setTaskID(String n) {
this.taskID = n;
}
public String getUniqueEventID() {
return this.uniqueEventID;
}
public void setUniqueEventID(String n) {
this.uniqueEventID = n;
}
}
The theme is the object sets the properties of javabean class and I have to get those values from UI.
In Jsp
<%
MessageBean consumer = msg.getMessages();
//Now here i want to iterate that consumer object
%>

As the MessagesBean seems to comply the javabeans specification, you can just use java.beans.Introspector for this.
MessageBean messageBean = consumerTool.getMessages();
// ...
BeanInfo beanInfo = Introspector.getBeanInfo(MessageBean.class);
for (PropertyDescriptor property : beanInfo.getPropertyDescriptors()) {
String name = property.getName();
Object value = property.getReadMethod().invoke(messageBean);
System.out.println(name + "=" + value);
}
This all is under the covers using the reflection API.
Update your edit reveals that you're intending to use this to present the data in JSP. This is then not really the right approach. Bite the bullet and specify every property separately. This way you've full control over the ordering.