Java Java Data Structures Efficiency! Using a Map to store Contact Methods

Not Sure What to Do, or How to Do It.

I Just Don't Know What to Do.

Challenge Task 1 of 3

In the next couple of steps, let's fix up this work in progress Contact model. This is going to be used in a Web application where the user can add different ways to contact a person.

In this first step, modify the addContactMethod method to store the information in the mContactMethods Map.


com/example/model/Contact.java
package com.example.model;

import java.util.Map;
import java.util.Set;
import java.util.HashMap;

public class Contact {
  private String mFirstName;
  private String mLastName;
  private Map<String, String> mContactMethods;

  public Contact(String firstName, String lastName) {
    mFirstName = firstName;
    mLastName = lastName;
    /* This stores contact methods by name
     * eg:  "phone" => "(555) 555-1234"
     */
    mContactMethods = new HashMap<String, String>();
  }

  public void addContactMethod(String method, String value) {
    // TODO: Add to the contact method map
  }

  /**
   * Returns the available contact methods.  eg: phone, pager,
   *
   * @return The name of the contact methods that are available
   */
  public Set<String> getAvailableContactMethods() {
    // FIXME: This should return the current contact method names.
    return null;
  }

  /**
   * Returns the value for the contact method if it exists, 
   *
   * @param methodName  The name of the contact method to look up.
   * @return The name of the contact methods that are available
   */
  public String getContactInfo(String methodName) {
    // FIXME: return the value for the passed in *methodName*
    return null;
  }

  public String getFirstName() {
    return mFirstName;
  }

  public String getLastName() {
    return mLastName;
  }

}

1 Answer

Rob Bridges
Rob Bridges
Java Web Development Techdegree Student 13,600 Points

Hey Isiah,

I can certainly try to help with this, but is there a certain part that you are having trouble with? I don't want to give the whole answer if that is not what you are looking for.

Thanks, give me a shout.

Can you just maybe give me something to work with, or part of the answer and explain it?

Rob Bridges
Rob Bridges
Java Web Development Techdegree Student 13,600 Points

Hey Isiah, sure, I've included the javadoc for maps. What this challenge is wanting you to do is in each task they are wanting to call a certain method on the map mContactMethods that has already been created. In the first task it's asking us to put the methods that are passed in into the map, looks like an excellent situation for the map.put method.

We'd sort out the first task by by calling the method.

mContactMethods.put(method, value);

I'll give you a shot at the other two, however don't hesitate to reach out if you need more help. The next two tasks in the challenge are wanting you to return certain parts of the map instead of null.

I'll give you a hint, look for a method that returns the keys, and a method that returns the value of the key that is passed in for the third task.

Don't hesitate to shout back if this doesn't clarify enough.