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

Damjan Vlaic
Damjan Vlaic
19,241 Points

---JAVA---

Can someone help me with this please, I'm getting error on line 35 in getAvailableContactMethods mehod?

In this task, let's fix the getAvailableContactMethods method. We want to return a set of the currently defined contact methods. HINT: How about a set of the keys from mContactMethods?

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

import java.util.HashSet;
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
    mContactMethods.put(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.
    Set<String> availableContacts = new HashSet<String>();
    for (String name : mContactMethods) {  // <---error is on this line
      availableContacts.add(name);
    }
    return availableContacts;
  }

  /**
   * 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

Anders Björkland
Anders Björkland
7,480 Points

mContactMethods is a HashMap. You are asked to return a Set of contactmethods. You could just return the keySet of mContactMethods like this: mContactMethods.keySet();

Or, as you are doing now, you could iterate over the keyset and add each key to your availableContacts. For this to work however, use the enhanced for-loop onthe keySet of mContactMethods.

Damjan Vlaic
Damjan Vlaic
19,241 Points

tnx for helping man, i get it now ;)