列表/哈希集中使用的自定义类

Question

I have a custom class that looks like below:

public class customClass(){
    private int keyCode;
    private boolean up;
    private String toTrigger;

    public String getTrigger();
    public boolean up();
    public int keyCode();
}

Whats the best way for performance to have a list of unique values?

I was thinking of a HashSet but how would i make sure its only unique instances of my customClass?

What do i need to override? Equals and HashCode? will that make sure that my Hash Set of CustomClass only have unique instances?

Thanks

Answer 1

If a.equals(b) is true then there hashcode() must also be same.

• Override both .equals() and .hashCode() in your custom class.

  Use the same fields of your custom class to calculate hashCode which you used to check equality in .equals().

• Yes it'll make sure that there are only unique instances of your customClass in hash-set. So go for it.