Is there a simple way to alphabetize a String Enumeration in Java?

问题

Just as the title says.

I tried messing around a bit with Collections.sort() on a List[] and the .sort() function of an ArrayList but I was never able to parse it back to an Enumeration.

Thanks!

EDIT:

Here's some pseduocode and further explanation. My goal is to take the keys() from a Hashtable and do complex operations involving each one, alphabetically.

My current process is:

Take a hash table I'm given
Form an enumeration from the ht
Run a while loop until the enumeration is empty

So the code is like this:

public void processData(Hashtable<String,GenericClass> htData)
{
    Enumeration<String> enData = htData.keys();

    while(enData.hasMoreElements())
    {
        String current = enData.nextElement();

        /*
         * DO COMPLEX PROCESS
         */
    }
}

The problem, is that the data in the enumeration has to be alphabetical (that is, the "complex process" must be done on each key in alphabetical order). Any solutions? Thanks!

回答1:

If you have a sorted list you can use

Collections.enumeration(myList)

to get it back to an enumeration... if I'm following you correctly..

EDIT:

You can do this...

List l = new ArrayList(ht.keySet());
Collections.sort(l)

回答2:

If you need to iterate over the items in order of their keys, maybe it's better to use a TreeMap instead of a Hashtable. Its keySet method will return the keys in order.

回答3:

What about storing your keys in an ArrayList to sort them?

    List<String> list = // create from htData.keys()
    Collections.sort(list);
    for(String s : list) {
    ...

回答4:

Following should work:

Enumeration<String> enumeration = dictionary.keys(); // unsorted enumeration        
List list= Collections.list(enumeration); // create list from enumeration 
Collections.sort(list);
enumeration = Collections.enumeration(list);

来源：https://stackoverflow.com/questions/1498615/is-there-a-simple-way-to-alphabetize-a-string-enumeration-in-java

标签

java

sorting

enumeration