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POright way to use collections in Java?
 

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  1. POright way to use collections in Java?
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    <p>I have the following code. However I am doubting about if it is the right way to implement it or not.</p> <p>What I mean is: in the collection framework there are many data structures to use and creating the class (<code>MemberList</code>) to manage the aggregations of many members can be implemented using <code>ArrayList</code>, <code>LinkedList</code>, priority queue ...</p> <p>I would like to use a data structure that fits with my needs, and that has the least Big O possible when it comes to searching, sorting, deleting, adding, modifying and deleting.</p> <pre><code>public class MemberList{ /** *a list of accounts existing in the database */ private static List&lt;Member&gt; members = new ArrayList&lt;Member&gt;(); /** * add a member to our member list * @param m the member to be added */ public static void Add(Member m) { members.add(m); /** * delete a member from our member list * @param m the member to be deleted */ public static void Delete(Member m) { Iterator&lt;Member&gt; it = members.iterator(); while(it.hasNext()) { if(m.equals(it.next())) { it.remove(); } } } /** * Search for a specific member in the member list * @param m the member that needs to be found * @return the reference of the object Member * @throws UserNotFoundExeption whether the member was not found in the list */ public static Member Search (Member m) throws UserNotFoundExeption { Iterator&lt;Member&gt; it = members.iterator(); while(it.hasNext()) { if(m.equals(it.next())) { return it.next(); }else{ UserNotFoundExeption ex = new UserNotFoundExeption(it.next().getUsername()); throw ex; } } return null; } /** * The login method enables checking whether the login was made successfully or not. if not, it can throw two * exceptions to handle the errors * @param member * @return * @throws UserNotFoundExeption * @throws FailedLoginException */ public static boolean login (Member m) throws UserNotFoundExeption,FailedLoginException { try{ Member member = Search(m); if (!m.authenticate(member.getPassword())) { FailedLoginException ex2 = new FailedLoginException (member.getPassword()); throw ex2; } else { return true; } }catch(UserNotFoundExeption ex){ throw ex; } } /** * this behavior modify attributes of the corresponding class * @param &lt;T&gt; this generic helps to accept any type of parameter change, hence we can change any type * @param m this is the member that need to change his information * @param choice the choice of which information to change * @param change the new change on the member attribute * @throws UserNotFoundExeption */ public static &lt;T&gt; void Modify(Member m, int choice, T change) throws UserNotFoundExeption { try{ Member member = Search(m); switch(choice) { case 1: member.setUsername((String)change); break; case 2: member.setPassword((String)change); break; case 3: member.setCommunity((Community)change); break; } }catch(UserNotFoundExeption ex){ throw ex; } } /** * display the member list objects information */ public static void Display() { Iterator&lt;Member&gt; it = members.iterator(); while(it.hasNext()) { System.out.println(it.next()); } } /** * Sort objects in the list */ public static void Sort() { Iterator&lt;Member&gt; it = members.iterator(); Member[] Members_Array = members.toArray(new Member[members.size()]); Member temp; for(int i = 0; i&lt;members.size(); i++) { for(int j = 0; j &lt; members.size() - (i+1); j++) { if(Members_Array[j].compareTo(Members_Array[j+1]) &gt; 0) { temp = Members_Array[j]; Members_Array[j] = Members_Array[j+1]; Members_Array[j+1] = temp; } } } } } </code></pre> <p>Thank you!</p>
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    1. USuser1680944
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    1. COJust out of curiosity: why is everything in your class static?
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      1. USmabi
    2. COAnd more to the point: unfortunately sorting and modification don't go well together. So an answer needs to take into consideration what gets used more: do you query your list a lot? Do you modify it each second or more?
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      1. USmabi
    3. CO.Delete()(.remove()), .Sort()(Collections.sort()) and .Search()(.indexOf(),.contains()) are usually already implemented and in most cases more efficient as any individual implementation. To the topic: as mabi already stated, decide what you need most(90% of the cases) and use the type of List that fits your needs.
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      1. POright way to use collections in Java?
      1. USMartin Weber
 

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