Re: Generics

From:
Owen Jacobson <angrybaldguy@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 11 Mar 2008 06:31:15 -0700 (PDT)
Message-ID:
<319e7dcf-2ca9-4316-b1da-f1c1b51a9121@s50g2000hsb.googlegroups.com>
On Mar 11, 8:59 am, Todd <todd.heident...@lmco.com> wrote:

On Mar 10, 5:13 pm, Lew <l...@lewscanon.com> wrote:

Todd wrote:

import java.util.StringTokenizer;
import java.util.Vector;


Don't use java.util.Vector. Use one of the List implementations that =

replaced

it in 1998, such as ArrayList.

    public <T> T getValue()
    {
        @SuppressWarnings( "unchecked" ) // TODO check cast=

 and don't

suppress
        Class <T> type = dataType.getClassType();


The need for an "unchecked" suppression is an indicator that you don't h=

ave

the generics quite right. Don't feel bad; with type erasure it isn't =

easy to

get generics exactly right, warning-free.

--
Lew


Please don't quote signatures.

Lew,

Question about ArrayList vs. Vector. I remember reading that one
should only use Vector since it is the only collection _guaranteed_ to
be thread-safe. Is this no longer considered true?


It depends on what you mean by "thread-safe". All of Vector's methods
are declared synchronized, which means that only one method may be in
progress on a single Vector at a time. However, this provides no
guarantees about coherency across multiple method calls, nor
particularly across iteration.

If you need the same promise from a List, you can use
Collections.synchronizedList (backingList) to construct a wrapper
around a List that performs the same synchronization that Vector
does. However, I've rarely found synchronizing on individual lists to
be all that useful, for the reasons I outlined above.

-o

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