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Java Java Data Structures Efficiency! Building the Model

Diego Marrs
Diego Marrs
8,243 Points
Posted by Diego Marrs
Diego Marrs
8,243 Points

Challenge 2 confusion...

Hello,

I'm doing challenge 2 for this video, and i'm stuck on what to do from here:

  public Set<String> getAvailableContactMethods() {
    // FIXME: This should return the current contact method names.
    Set<String> avaliableContactMethods = new HashSet<String>();
    return avaliableContactMethods;
  }

I'm not sure how you are suppose to return the current contact method names...if 'methodName' is a 'getContactInfo' parameter.

Thanks!

1 Answer

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

Hi Diego - The HashMap class has the keySet() method that returns a set of all the keys. Call that method on mContactMethods and return the result.

Diego Marrs
Diego Marrs
8,243 Points
Diego Marrs
Diego Marrs
8,243 Points

Thanks!

Also, just curious, was 'keySet()' covered before?

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

You're welcome. Yes, keySet() was covered in the Maps video at 05:07.

Diego Marrs
Diego Marrs
8,243 Points
Diego Marrs
Diego Marrs
8,243 Points

Ah, okay.

I hope you don't mind, but could you also help me a little with challenge 3? Here is my code so far:

  public String getContactInfo(Set<String> methodName) {
    // FIXME: return the value for the passed in *methodName*
    methodName = new HashSet<String>();
    for (String method : getAvaliableContactMethods()) {

    }
    return methodName;
  }
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

For part 3 you need to return a single value for the passed in key methodName, so there is no need for a loop or a HashSet. You just need one line of code that uses HashMaps's get() method to return the value associated with the key methodName.