HashSet - 직접 구현하는 Set4 - 제네릭과 인터페이스 도입

package collection.set;

import java.util.Arrays;
import java.util.LinkedList;

public class MyHashSetV3<E> implements MySet<E> {

    static final int DEFAULT_INITIAL_CAPACITY = 16;

    private LinkedList<E>[] buckets;

    private int size = 0;
    private int capacity = DEFAULT_INITIAL_CAPACITY;

    public MyHashSetV3() {
        initBuckets();
    }

    public MyHashSetV3(int capacity) {
        this.capacity = capacity;
        initBuckets();
    }

    private void initBuckets() {
        buckets = new LinkedList[capacity];
        for (int i = 0; i < capacity; i++) {
            buckets[i] = new LinkedList<>();
        }
    }

    private int hashIndex(E value){
        int hashCode = value.hashCode();
        return Math.abs(hashCode) % capacity; //-를 없앰, 절대값
    }

    public boolean add(E value){
        int hashIndex = hashIndex(value);
        LinkedList<E> bucket = buckets[hashIndex];
        if(bucket.contains(value)){
            return false;
        }
        bucket.add(value);
        size++;
        return true;
    }

    public boolean contains(E searchValue){
        int hashIndex = hashIndex(searchValue);
        LinkedList<E> bucket = buckets[hashIndex];
        return bucket.contains(searchValue);
    }

    public boolean remove(E value){
        int hashIndex = hashIndex(value);
        LinkedList<E> bucket = buckets[hashIndex];
        boolean result = bucket.remove(value);
        if(result){
            size--;
            return true;
        }else{
            return false;
        }
    }

    public int getSize() {
        return size;
    }

    @Override
    public String toString() {
        return "MyHashSetV3{" +
                "buckets=" + Arrays.toString(buckets) +
                ", size=" + size +
                ", capacity=" + capacity +
                '}';
    }
}

 

 

package collection.set;

public class MyHashSetV3Main {
    public static void main(String[] args) {
        MySet<String> set = new MyHashSetV3<>(10);
        set.add("A");
        set.add("B");
        set.add("C");
        System.out.println(set);

        //검색
        String searchValue = "A";
        boolean result = set.contains(searchValue);
        System.out.println("set.contains(" + searchValue +")" + result);
    }
}

 

 

실행 결과

MyHashSetV3{buckets=[[], [], [], [], [], [A], [B], [C], [], []], size=3, capacity=10}
set.contains(A)true