CODEWITHSUNDEEP
javahashmapinstance
SwampThing
SwampThing

Reputation: 125

Instance of class as key in hashmap

I have this class:

 public class Offer {

        private Integer id;
        private String description;
        private Double price;
        private String currency;
        private Date timeExpired;

        public Offer(Integer id, String description, Double price, String currency, Date timeExpired){

            this.id = id;
            this.description = description;
            this.price = price;
            this.currency = currency;
            this.timeExpired = timeExpired;
        }
}

I want to create a hashmap with key that refers to id of the class Offer and value as Offer. 

HashMap<id of Offer(?),Offer> repo = new HashMap<id of Offer(?),Offer>();

How can I do that?

How assign each Offer id as key and the Offer objects as values on Hashmap repo? I mean method repo.put(?)

Upvotes: 0

Views: 964

Answers (1)

azro
azro

Reputation: 54148

Because the id is an Integer your need a HashMap<Integer, Offer>:

public static void main(String[]args){
    HashMap<Integer, Offer> map = new HashMap<Integer, Offer>();

    // First way
    map.put(1038, new Offer(1038, "foo", 10.20, "bar", new Date()));

    // Second way
    Offer o1 = new Offer(1038, "foo", 10.20, "bar", new Date());
    map.put(o1.getId(), o1);

}

Tips :

  • use int and double rather than Integer or Double if you don't really need the objects (int vs Integer)
  • use LocalDate instead of Date it's the latest version, and easier to use

Upvotes: 2

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