Re: unsafe or unchecked operations
On 25 Jun, 17:52, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
On Sat, 21 Jun 2008 18:50:36 GMT, "gg" <g...@Edm.noMail.net> wrote,
quoted or indirectly quoted someone who said :
I have not used java in for a long time skipping 1.5. I have using .net
Generics are by far the most complicated thing I have encountered in
Java. I know a number of "recipes" that work, but when you get in the
nested <> and ? I have to find something very close to what I want to
do to copy. Sometimes after I read a tutorial, it feels a little
clear, but only for a day or so. It is inherently too complicated for
the benefits it offers.
I hear it may change in JDK 1.7
--
Roedy Green Canadian Mind Products
The Java Glossaryhttp://mindprod.com
On 25 Jun, 17:52, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
On Sat, 21 Jun 2008 18:50:36 GMT, "gg" <g...@Edm.noMail.net> wrote,
quoted or indirectly quoted someone who said :
I have not used java in for a long time skipping 1.5. I have using .net
Generics are by far the most complicated thing I have encountered in
Java. I know a number of "recipes" that work, but when you get in the
nested <> and ? I have to find something very close to what I want to
do to copy. Sometimes after I read a tutorial, it feels a little
clear, but only for a day or so. It is inherently too complicated for
the benefits it offers.
I hear it may change in JDK 1.7
--
Roedy Green Canadian Mind Products
The Java Glossaryhttp://mindprod.com
I hope it does change in JDK 1.7. I am not a Java guru, but it was my
first class in college on programming. Wow, I couldn't understand what
I was supposed to do. Deprecated warnings I understand. Look for a
new method. But with 'unchecked' I need to generify my method, cast,
or strong type my variables/objects? Which ones?
Of course, I might be guilty of looking for the 'easy' button and
maybe I should sit down for a week of studying generics in Java. But
really, there is not much ROI when all I wanted to change was a
cosmetic text in the program someone else wrote back in JDK 1.4 and
not any logic of the program.
Things I tried:
1. Tried more recent example file ExampleFileView.java but get the
same warning
2. Tried casting similar to example above from Knute J but get
warning.
Question:
But how does casting happen when 'filters != null'?
Example from above:
Hastable<String,CustomFileFilter> filters =
new Hashtable<String,CustomFileFiler>(5);
Applying to file ExampleFileFilter.java:
Was:
/**
* Creates a file filter.
*/
public ExampleFileFilter() {
this.filters = new Hashtable();
}
/**
* Adds a filetype "dot" extension to filter against.
*/
public void addExtension(String extension) {
if(filters == null) {
filters = new Hashtable(5);
}
filters.put(extension.toLowerCase(), this);
fullDescription = null;
}
Tried:
public ExampleFileFilter() {
this.filters = new Hashtable<String,ExampleFileFilter>();
} // DR: I think the 'this.filters' needs to be casted as well.
public void addExtension(String extension) {
if(filters == null) {
Hashtable<String,ExampleFileFilter> filters = new
Hashtable<String,ExampleFileFilter>(5);
} // DR: How does casting happen when 'filters != null'?
filters.put(extension.toLowerCase(), this);
fullDescription = null;
}
Maybe it's the 'put' method. I learned about warning suppression and
generics. Couldn't apply because I have little knowledge on how to
'generify' the 'put' method. I briefly considered digging into
finding the method 'put' but really sounded like a bad idea and not
much ROI compared with the alternatives (see 'What I did').
What I did:
1. Ignored the JDK 1.6 warning
2. Found out the JRE on the server is still at 1.4
3. Went back to compiling in JDK 1.4 with no warning