java sort hashtable with object value by the objecs string parameter

I have an hashable that contains a string key , and a class object value:

Hashtable<String,myclass>m_class_table = new Hashtable<String开发者_运维问答,myclass>();

inside 'myclass' I have a String field value,

I need to sort my hashtable according to this string value.

I can't just sort it by the hashtable values beacuse it is an object..

How can this be done?

Thank's In Advance.

I need to sort my hashtable according to this string value.

A hashtable is not a sorted data structure.

You can use some SortedMap, such as a TreeMap but those data structures sorts on the keys, so that will only work if the key equals the string-field of the object pointed to.

I can't just sort it by the hashtable values beacuse it is an object..

You need to provide a Comparator<myclass>, or, let myclass implement the Comparable interface.

Depending on how you iterate over the hash-table, you could perhaps do like this:

List<myclass> myObjects = new ArrayList<myclass>(m_class_table.values());
Collections.sort(myObjects, new Comparator<myclass>() {
    @Override
    public int compare(myclass o1, myclass o2) {
        o1.stringField.compareTo(o2.stringField);
    }
});

and then iterate over the myObjects list. (Elements in a List are ordered.)

A slight variation on aioobe's answer: I'd create a List of the Map entries and sort that list. That way you still have access to the complete map entries.

Map<String, MyClass> map = new HashMap<String, MyClass>();
// add some entries

List<Entry<String,MyClass>> entryList = 
     new ArrayList<Entry<String,MyClass>>(map.entrySet());
Collections.sort(entryList, new Comparator<Entry<String,MyClass>>() {
    public int compare(
        Entry<String, MyClass> first, Entry<String, MyClass> second) {
            return first.getValue().getFoo()
                        .compareTo(second.getValue().getFoo());
    }
});