Nested if's

[Victoria Preston]

I am supposed tochange this from a nested if to something else but I don't know what else to changed it to any help would be appricated.

public static int getAdjustmentMinutes(String tz)
throws NoSuchTimeZoneException
 {   // Only CST implemented so far
if (tz.equals("CST"))
          return -360;
if (tz.equals("UTC"))
  return 1;
if(tz.equals("CET"))
  return -60;
if(tz.equals("AST"))
  return -240;
if(tz.equals("EST"))
  return -300;
if(tz.equals("MST"))
  return -420;
if(tz.equals("PST"))
  return -480;
if (tz.equals("AKST"))
  return -540;
if (tz.equals("HAST"))
  return -600;
if (tz.equals("NST"))
  return -345;
else
throw new NoSuchTimeZoneException("No such time zone: "+tz);
}    

[Garrett Rowe]

You could implement it usning enums.

[Victoria Preston]

i think he wanted me to get rid of the if's all together...doesn't emun's use ifs

[Joanne Neal]

You could use a HashMap with the timezones as keys and the minutes as Integer values.
[ March 31, 2006: Message edited by: Joanne Neal ]

[Victoria Preston]

whats a hashmap

[Paul Clapham]

Or if this is a real-life question and not just a beginner's programming exercise, you could replace the whole thing by calls to various methods in the TimeZone class. No "ifs" would be required there.

[Garrett Rowe]

You dont have to use if's if you use enums. You could use the valueOf() method.

public class Foo
{
   public enum Bar
   {
     A(1), B(3), C(5), D(7);
     Bar(int i)
     {
        this.i = i;
     }
 
     public int getI()
     {
        return i;
     }
     private int i;
   }
 
   public int doSomething(String str)
   {
      Bar b = null;
      try
      {
         b = Bar.valueOf(str);
      }
 
      catch (IllegalArgumentException ex)
      {
         throw SomeOtherException();
      }
 
      return b.getI();
   }
}

[Victoria Preston]

Well I am in intermidate programming but its the beginner stuff I don't understand.....I am having trouble with the basic concepts...thats why I post here

[Stan James]

The Map approach is something I use all the time. Look at the JavaDoc for all the details. Here's a method that might be similar to yours:

public void init()
{
   map.put("bread", new Integer(125) ); // $1.25
   map.put("milk",  new Integer(300) ); // $3.00
   ...
}
public int price( String item )
{
   Integer price = (Integer)map.get( item );
   return price.intValue();
}

See if you can read up on HashMap enough to do somethin glike that.

[Tony Morris]

Sounds like the perfect fit for the Strategy Design Pattern. Some proponents of language theory proclaim that a single if/else is a broken construct and does not belong in a complete language. While I haven't bought that argument just yet, I certainly agree with the more wider (though still small relative to the critical mass) understanding that a if/else/else (3 or more statement bodies) should always be avoided. I even know a few who claim that for loops are flawed constructs!! I haven't bought that argument, simply because I don't understand it in completeness yet, but I suspect that they are ultimately right. For the same reason - appropriate abstraction/accurate requirement expression - switch/case constructs should always be avoided.

The point being, I suspect that your teacher (a knowledagable academic?) is probably trying to teach you something related to this and I encourage you to pursue it further.

The Strategy Design Pattern - one of few legitimate design patterns - is implemented in Java almost always using a java.util.Map. If you wish to go for further purity (but falling infinitely short implied by Java), you might want to consider net.tmorris.adt.map.Map - or just write the interface yourself. Minimalism is paramount even though it is often unachievable under a given context. So often I observe suffering as a result of excessive expression of requirement/contract, and worse, I observe the resulting "problem" attributed to a consequence, instead of the underlying flaws.

Good to hear of a tertiary institution on the right path ...if indeed that is what is happening.

[Ken Blair]

Originally posted by Tony Morris:
Good to hear of a tertiary institution on the right path ...if indeed that is what is happening.

For all we know the instructor is trying to push them towards a type-safe enum and a switch/case so I wouldn't get my hopes up too much.

As for the OP's question, I think using a Map is your best bet and someone already gave you sample code for that.