How to get values and keys from HashMap?

Question

I\'m writing a simple edit text in Java. When the user opens it, a file will be opened in JTabbedPane. I did the following to save the files opened:

Answer 1

You could use iterator to do that:

For keys:

for (Iterator <tab> itr= hash.keySet().iterator(); itr.hasNext();) {
    // use itr.next() to get the key value
}

You can use iterator similarly with values.

Answer 2

With java8 streaming API:

List values = map.entrySet().stream().map(Map.Entry::getValue).collect(Collectors.toList());

Answer 3

for (Map.Entry<String, Tab> entry : hash.entrySet()) {
    String key = entry.getKey();
    Tab tab = entry.getValue();
    // do something with key and/or tab
}

Works like a charm.

Answer 4

To get values and keys you could just use the methods values() and keySet() of HashMap

public static List getValues(Map map) {
    return new ArrayList(map.values());
}

public static List getKeys(Map map) {
    return new ArrayList(map.keySet());
}