▪️Test108.java

public class Test108<E> {
    private E item;
    private KeyType keyType;
    private long count;

    public void put(E o) {
        this.item = o;
    }

    public E get() {
        this.count++;
        switch (this.keyType) {
        case PADLOCK:
            if (count > 1024)
                return null;
            break;

        case BUTTON:
            if (count > 10000)
                return null;
            break;

        case DIAL:
            if (count > 30000)
                return null;
            break;

        case FINGER:
            if (count > 1000000)
                return null;
            break;

        }
        // クラスで宣言した変数item
        this.count = 0;
        return this.item;

    }

}

▪️KeyType.java
public enum KeyType {
    PADLOCK, BUTTON, DIAL, FINGER;

}