일반 싱글톤 방식의 테스트용 Temporary Data Access Object

import java.util.HashMap;

public class DataAccessObject {

    private static DataAccessObject instance;

    private HashMap<String, Object> objectHash;

    private DataAccessObject() {
        objectHash = new HashMap<String, Object>();
    }

    public static synchronized DataAccessObject getInstance() throws Exception {
        if (instance == null) {
            instance = new DataAccessObject();
        }
        return instance;
    }

    public Object get(String key) {
        return objectHash.get(key);
    }

    public void set(String key, Object value) {
        objectHash.put(key, value);
    }

    public void delete(String key) {
        objectHash.remove(key);
    }
}