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

Audi Lou Abatayo
Audi Lou Abatayo
2,645 Points

Why methodName?

I really don't understand where 'methodName' is in the mContactMethods. Last time I checked the map only had 'String method, String value' so if I were to get 'methodName' in the mContactMethod wouldn't a null or error appear??

Or did I misunderstand here, and I should just follow the instructions to return the value?

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
    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.
    return  mContactMethods.keySet();
  }

  /**
   * 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 mContactMethods.get(methodName);

  }

  public String getFirstName() {
    return mFirstName;
  }

  public String getLastName() {
    return mLastName;
  }

}

1 Answer

Kourosh Raeen
Kourosh Raeen
23,703 Points

The methodName is a String key in the map, something like: "Phone", and the value would be another String, like: "(555) 555-1234", so mContactMethods.get("Phone ") would return "(555) 555-1234".