Ok, so here goes:
I'm building a thesaurus using a HashMap <String,ArrayList<String>> to hold words and their synonyms (this data structure is required).
For the purpose of the assignment, the synonymity relation is considered transitive. (We can imagine the thesaurus as a graph). What I'm trying to accomplish is to print this graph in a text file, with a connected component on each line. In other words, all the words that can be pooled together as synonyms should go on a single line.
public void save() {
try {
FileWriter fw = new FileWriter(defaultDefinitionFile);
BufferedWriter out = new BufferedWriter(fw);
Set<String> keys = thesaurus.keySet();
Iterator<String> ite = keys.iterator();
while (ite.hasNext()) {
String key = ite.next();
out.write(key);
ArrayList<String> synonyms = thesaurus.get(key);
Iterator<String> i = synonyms.iterator();
while (i.hasNext()) {
String syn = i.next();
out.write(","+syn);
keys.remove(syn);
}
out.write("\r\n");
}
out.close();
fw.close();
}
catch (Exception e) {
System.out.println("Error writing to file");
e.printStackTrace();
}
}
This is how I pictured it to happen: Print a word along with each of its synonyms, then remove those synonyms from the data structure so we don't have duplicate lines.
Problem is of course that I can't delete anything while i'm iterating over the content of the hashmap.
Any alternative approaches I'm missing?
P.S. I'm keeping the 'graph' metaphor throughout only because i needed the title to be eloquent and succint. I understand that this metaphor is limited in usefulness.