Initializing a collection

Question

Hi everybody,
This might be an easy question, but I can't figure out why the method below doesn't compile. I'm trying to, when reading in a file, either get a list of unique words, or a map of unique words with frequencies. I thought that returning a Collection would do the trick, but I'm getting a compiler error, a type mismatch, anytime I declare a collection as a map. I also get errors anytime I try to use a map. I have all the proper imports, so I know that's not it. If anyone could explain to me why this is, and how to fix this method (preferably without warnings), I'd be much obliged. My code is:
public Collection readWords( String wordType, boolean frequencies ) throws IOException {
          Collection words;
          if( wordType.equals( "alpha" ) ) {
               if( !frequencies ) words = new TreeSet<String>();
               else words = new TreeMap<String, Integer>();
          else if( wordType.equals( "order" ) ) {
               if( !frequencies ) words = new LinkedHashSet<String>();
               else words = new LinkedHashMap<String, Integer>();
          else if( wordType.equals( "random" ) ){
               if( !frequencies ) words = new HashSet<String>();
               else words = new HashMap<String, Integer>();
          String line = null;
          while( ( line = reader.readLine() ) != null ) {
               StringTokenizer parser = new StringTokenizer( line, delimiters );
               while( parser.hasMoreTokens() ) {
                    if( !frequencies ) words.add( parser.nextToken().toLowerCase() );
                    else {
                         String next = parser.nextToken();
                         if( !words.containsKey( next ) ) words.put( next, 1 );
                         else {
                              int value = words.get( next );
                              words.put( next, value + 1 );
          return words;
     }Thanks,
Jezzica85
Edited by: jezzica85 on May 9, 2008 11:26 PM
Edited by: jezzica85 on May 9, 2008 11:27 PM

Answer 1

A List or a Set is a Collection.
You can get a Set<Map.Entry<K,V>> from a map with [entrySet()|http://java.sun.com/j2se/1.5.0/docs/api/java/util/Map.html#entrySet()]
but why don't you just deal with the map?