My name
is
Jon Skeet

java constructor handling lack of arguments

i have this code here for a person details and the person should be intialized always whatever the number of possible arguments given ,like for example only height and age or salary and age
and i find it difficult to declare a constructor for every combination of arguments , is there a more optimal solution than that ??

class person {
    public static final int defalut_salary=1000;
    public static final int default_age=20;
    public static final double default_height=6;
    public static final String default_name="jack";

    protected int salary;
    protected int age;
    protected double height;
    protected String name;  

    person(){       
    }
}

I would suggest using the Builder pattern:

public final class Person {
    private final int salary;
    private final int age;
    private final double height;
    private final String name;

    public Person(int salary, int age, double height, String name) {
        this.salary = salary;
        this.age = age;
        this.height = height;
        this.name = name;
    }

    // Getters or whatever you want

    public static class Builder {
        // Make each field default appropriately
        private int salary = 1000;
        private int age = 20;
        private double height = 6;
        private String name = "jack";

        public Builder setSalary(int salary) {
            this.salary = salary;
            return this;
        }

        // Ditto for other properties

        public Person build() {
            return new Person(salary, age, height, name);
        }
    }
}

Usage:

Person person = new Person.Builder().setAge(25).setHeight(15).build();

You can perform validation in the Person constructor, and if you want to make any of the fields mandatory, you could take those in the Builder constructor.

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