title: Iterate over a HashMap with multiple values per key
body: <p>I am currently learning sets and maps through university (still using Java 7). </p>
  
  <p>They have given us a half finished to-do list app to complete. Currently the to-do list takes three String local variables to allow the user to state a job (aJob), a time to do it (aTime) and a date to do it (aDate).</p>
  
  <p>The app also has an instance variable (today) that holds todays date. </p>
  
  <p>I need to come up with a way to check the HashMap for any tasks that are due today. So I need to be able to query just the HashMap values attributed by the aDate local variable.</p>
  
  <p>I know that to iterate Maps that I can place the keys or the values into a Set and then iterate over the set - not a problem. But if I use the values() method (within the Map class) to put these into a set - it places all three Strings per key into the set. I just want to move the aDate values into a set. </p>
  
  <p>Any ideas? </p>
  
  <p>I only seem to be able to find examples where the Maps have just a single Key and Single Value. This list has a single key and three values per key. </p>
  
  <p>Any pointers would be good? </p>
  
  <p>Kind Regards</p>
  
  <p>Edit.....</p>
  
  <p>Just thought I would add some code to help as there have been several different approaches - which I am all very greatful for. But not sure if they suit my needs....</p>
  
  <p>The Job Class is constructed as such...</p>
  
  <pre><code>public Job(String aJob, String aDate, String aTime)
  {
    Job = aJob;
    date = aDate;
    time = aTime;
  }
  </code></pre>
  
  <p>I then create the map within the instance declarations for the To Do List class....</p>
  
  <pre><code>Map&lt;Integer, Job&gt; toDoList = new HashMap&lt;&gt;();
  </code></pre>
  
  <p>So I need to know the best way to iterate over this map, but it is only the Job attribute 'aDate' that is possibly going to hold the value I am after. </p>
  
  <p>Not sure if that helps at all?</p>
  
  <p>Kind Regards</p>