Re: How do I set up CollapsableHashtable to take parameters?

Joshua Cranmer <>
Tue, 20 Mar 2007 21:13:15 GMT
<L7YLh.2298$zN.1684@trndny03> wrote:

On Mar 20, 12:18 pm, Tom Hawtin <> wrote:

The main point of still using Hashtable instead of HashMap is that
Hashtable methods are generally synchronized. So, it would make sense
for this method to be synchronized to.

Lost me completely.

Synchronization incurs extra overhead in order to ensure that multiple
threads cannot access the data structure at the same time. If your
application is not multithreaded, then synchronization is just useless

           Enumeration keys = this.keys();

Enumeration<K> would be better.

I actually implemented that after posting this, so I got one of them

           while (keys.hasMoreElements()) {

Mixing operations on a Enumeration/Iterator and the original object is
asking for trouble. Fortunately Iterator has a remove method.

I don't understand, sorry.

What he is trying to say is that mixing the methods of an Enumeration
with methods on the Hashtable it references opens up BIG problems.

A better way to write this would be entrySet().clear(); (or
keySet().clear();). If really want to use a loop:

             for (
                 Iterator<K> iter = keySet().iterator();
             ) {

but it's more efficient to do it in one go.

I don't know of a way you could do something like that in "one go",
please show me.

Is to use keySet.clear() or something like that. does not take
    private Hashtable<String, CollapsableHashtable<String, String>>

Are you sure you have the up to date version compiled? The obvious
problem is not forcing a recompile. I suggest making sure your .class
files are deleted and having another go.

Tom Hawtin

I'm using NetBeans 5.5 IDE, wouldn't have a clue as to how to do that
within NetBeans, sorry

I don't use NetBeans myself (vim + command-line for me!), but there
should be a tool in there to clear the compiled code directory...

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