Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

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

this code is not working can some1 explain?

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) {
    mContactMethods.add(method, value);
  }

  /**
   * 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;
  }

}

2 Answers

Rob Bridges
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Rob Bridges
Full Stack JavaScript Techdegree Graduate 35,459 Points

Hey Admire, I'd be happy to help you with the first part, you did a really good job getting through it and you're super close on getting past it, however when adding items to a map the command is .put()

give

mContactMethods.put(method, value);

a try and see how that works. No big deal, just looks like a little confusion.

Don't hesitate to give me a shout if you have any more questions. Also for the other questions in this challenge I recommend you use this.

Sean M
Sean M
7,344 Points

You are calling the mContactMethods, and specifying the string's method and value. Therefore:

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