[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
Re: [cross-project-issues-dev] org.eclipse.equinox.common has added generics to API in org.eclipse.core.runtime package

Yeah, this basically hides the unsafe cast in the implementation of Class#cast(..). It has its advantages and disadvantages:

Pro: Performs an additional dynamic Class#isInstance(..) check that throws a CCE at the place where the unsafe cast happens => fail-fast is good (although the cast at the caller side also won't be far away; and that's how it used to work in the past).

Contra: Is less explicit than the SuppressWarnings version, since the type safety problem is not immediately visible at the code location where the unchecked cast happens.

=> adapter.cast(..) is OK for me, but not a must.

Markus



From:        "Andrey Loskutov" <loskutov@xxxxxx>
To:        cross-project-issues-dev@xxxxxxxxxxx
Cc:        "General development mailing list of the Eclipse project." <eclipse-dev@xxxxxxxxxxx>, Cross project issues <cross-project-issues-dev@xxxxxxxxxxx>
Date:        2015-02-20 15:35
Subject:        Re: [cross-project-issues-dev] org.eclipse.equinox.common has added generics to API in org.eclipse.core.runtime package
Sent by:        cross-project-issues-dev-bounces@xxxxxxxxxxx




Hi,
Before everyone starts to change getAdapter() implementation, please consider to user warning-free alternative:
 
Instead of writing:
 
        @SuppressWarnings("unchecked")
       public <T> T getAdapter(Class<T> adapter) {
               if (ICompilationUnit.class.equals(adapter))
                       return (T) getCompilationUnit();
               return null;
       }

 
use Class.cast() API:

       public <T> T getAdapter(Class<T> adapter) {
               if (ICompilationUnit.class.equals(adapter))
                       return adapter.cast(getCompilationUnit());
               return null;
       }

 
Kind regards,
Andrey Loskutov

http://google.com/+AndreyLoskutov
 
 
Gesendet: Freitag, 20. Februar 2015 um 15:21 Uhr
Von:
"Thomas Watson" <tjwatson@xxxxxxxxxx>
An:
"Cross project issues" <cross-project-issues-dev@xxxxxxxxxxx>, "General development mailing list of the Eclipse project." <eclipse-dev@xxxxxxxxxxx>
Betreff:
[cross-project-issues-dev] org.eclipse.equinox.common has added generics to API in org.eclipse.core.runtime package

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=442021

Markus Keller wrote up an nice summary of what consumers should do to fix any warnings that may be caused by this change at
https://bugs.eclipse.org/bugs/show_bug.cgi?id=442021#c25

Here is a copy of the recommendations if you are going to compile against the latest version of org.eclipse.equinox.common:


1. In MANIFEST.MF, update your Require-Bundle:  org.eclipse.core.runtime;bundle-version="[3.11.0,4.0.0)", or org.eclipse.equinox.common;bundle-version="[3.7.0,4.0.0)", or update your Import-Package: org.eclipse.core.runtime; version="[3.5,4.0)"


2. If your bundle re-exports one of these bundles, then you also have to make sure the minor version is incremented.


3. Remove unnecessary casts (Clean Up, or Problems view > Quick Fix > Select All)


4. Update implementations of IAdaptable#getAdapter(Class<T>), unless you override another implementation of that method that still uses the old signature.


Typical change:
Old:
       public Object getAdapter(Class adapter) {
               if (ICompilationUnit.class.equals(adapter))
                       return getCompilationUnit();
               return null;
       }


New:
       @SuppressWarnings("unchecked")
       public <T> T getAdapter(Class<T> adapter) {
               if (ICompilationUnit.class.equals(adapter))
                       return (T) getCompilationUnit();
               return null;
       }


5. Update implementations of IAdapterFactory


Hint for 4. & 5.:
- Open Type Hierarchy on IAdaptable, etc.
- In the view menu, select a working set that contains your projects
- In the methods list of the Type Hierarchy view, select the methods, and then click the first toolbar button (Lock View and Show Members in Hierarchy)



Tom


_______________________________________________ cross-project-issues-dev mailing list cross-project-issues-dev@xxxxxxxxxxx To change your delivery options, retrieve your password, or unsubscribe from this list, visit
https://dev.eclipse.org/mailman/listinfo/cross-project-issues-dev_______________________________________________
cross-project-issues-dev mailing list
cross-project-issues-dev@xxxxxxxxxxx
To change your delivery options, retrieve your password, or unsubscribe from this list, visit
https://dev.eclipse.org/mailman/listinfo/cross-project-issues-dev