CODEWITHSUNDEEP
javainheritancedeclarationnested-class
lephleg
lephleg

Reputation: 1764

Declaring a nested class in Java

I'm a bit confused with subclasses. Here's my code:

public class MedHistory {

    private String grafts;
    private String allergies;
    private String diseases;
    private String surgeries;
    private String medicalTreatment;

    //Constructors (#2)

    public MedHistory(String allergies, String diseases, String grafts,
            String treatments, String surgeries) {
        this.allergies=allergies;
        this.diseases=diseases;
        this.grafts=grafts;
        this.medicalTreatment=treatments;
        this.surgeries=surgeries;
    }

    public MedHistory() {
        this.allergies="";
        this.diseases="";
        this.grafts="";
        this.medicalTreatment="";
        this.surgeries="";
    }

    //Getters 
    public String getGrafts() {
        return grafts;
    }

    public String getAllergies() {
        return allergies;
    }

    public String getDiseases() {
        return diseases;
    }

    public String getSurgeries() {
        return surgeries;
    }

    public String getMedicalTreatment() {
        return medicalTreatment;
    }

    //Setters 

    public void setGrafts(String grafts) {
        this.grafts = grafts;
    }

    public void setAllergies(String allergies) {
        this.allergies = allergies;
    }

    public void setDiseases(String diseases) {
        this.diseases = diseases;
    }

    public void setSurgeries(String surgeries) {
        this.surgeries = surgeries;
    }

    public void setMedicalTreatment(String medicalTreatment) {
        this.medicalTreatment = medicalTreatment;
    }

    public class FemMedHistory extends MedHistory {

        private List<Birth> births = new ArrayList<Birth>();

        //Constructors (#2)

        public FemMedHistory(String allergies, String diseases, String grafts,String treatments, String surgeries, List<Birth> birthlist) {
            super(allergies,allergies,grafts,treatments,surgeries);
            this.births=birthlist;
        }

        public FemMedHistory() {
            super();
            this.births=null;
        }

        //Getter

        public List<Birth> getBirths() {
            return this.births;

        }

        //Setter

        public void setBirths(List<Birth> list) {
            this.births=list;
        }

    }
}

When I try to create an new FemMedHistory object like this:

List<Birth> list = new ArrayList<Birth>();
list.add(new Birth(new GregorianCalendar(2011,4,10),"kaisariki",4));
FemMedHistory female = new FemMedHistory("allergia2","astheneia2","emvolia2","farmekeutiki agwgi2", "xeirourgeia2", list);

I get the error:

No enclosing instance of type MedHistory is accessible. Must qualify the allocation with an enclosing instance of type MedHistory (e.g. x.new A() where x is an instance of MedHistory).

So, which is the right way to use a subclass?

Upvotes: 2

Views: 293

Answers (3)

Marko Topolnik
Marko Topolnik

Reputation: 200148

Long story short: cut all the FemMedHistory code and paste it into FemMedHistory.java. The way it is now you have involved Java concepts which you have not yet mastered. Also, that class really does belong in a separate file.

Upvotes: 3

greedybuddha
greedybuddha

Reputation: 7507

When you declare a nested class it only available through the Outer class.

To access it outside, you will need to either make the FemMedHistory class static.

public static class FemMedHistory extends MedHistory {...}

access it through the MedHistory class

MedHistory.FemMedHistory myMedHistory = ...

or declare it in it's own Java file.

Upvotes: 5

Keppil
Keppil

Reputation: 46209

You have declared your subclass as an inner class, which means that you can't create an instance of it without first creating an instance of the containing class.

The most common way to solve this is to declare it as a separate class, which would get rid of your error.

Upvotes: 3

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