On Sun, Nov 25, 2012 at 6:27 AM, Martin Grigorov <[email protected]> wrote:
> Hi,
>
>
> On Sat, Nov 24, 2012 at 8:16 PM, <[email protected]> wrote:
>>
>> Updated Branches:
>> refs/heads/master 48044610a -> 65dd7b32e
>>
>>
>> add a serialization-safe class wrapper
>>
>>
>> Project: http://git-wip-us.apache.org/repos/asf/wicket/repo
>> Commit: http://git-wip-us.apache.org/repos/asf/wicket/commit/65dd7b32
>> Tree: http://git-wip-us.apache.org/repos/asf/wicket/tree/65dd7b32
>> Diff: http://git-wip-us.apache.org/repos/asf/wicket/diff/65dd7b32
>>
>> Branch: refs/heads/master
>> Commit: 65dd7b32ea4f91862353ab0f7bafe3bca5e271ea
>> Parents: 4804461
>> Author: Igor Vaynberg <[email protected]>
>> Authored: Sat Nov 24 11:16:32 2012 -0800
>> Committer: Igor Vaynberg <[email protected]>
>> Committed: Sat Nov 24 11:16:32 2012 -0800
>>
>> ----------------------------------------------------------------------
>> .../wicket/util/reference/ClassReference.java | 72 +++++++++++++++
>> 1 files changed, 72 insertions(+), 0 deletions(-)
>> ----------------------------------------------------------------------
>>
>>
>>
>> http://git-wip-us.apache.org/repos/asf/wicket/blob/65dd7b32/wicket-core/src/main/java/org/apache/wicket/util/reference/ClassReference.java
>> ----------------------------------------------------------------------
>> diff --git
>> a/wicket-core/src/main/java/org/apache/wicket/util/reference/ClassReference.java
>> b/wicket-core/src/main/java/org/apache/wicket/util/reference/ClassReference.java
>> new file mode 100644
>> index 0000000..7653633
>> --- /dev/null
>> +++
>> b/wicket-core/src/main/java/org/apache/wicket/util/reference/ClassReference.java
>> @@ -0,0 +1,72 @@
>> +package org.apache.wicket.util.reference;
>> +
>> +import java.io.Serializable;
>> +import java.lang.ref.WeakReference;
>> +
>> +import org.apache.wicket.Application;
>> +
>> +/**
>> + * A serialization-safe reference to a {@link Class}
>> + *
>> + * @author igor
>> + *
>> + * @param <T>
>> + * type of class
>> + */
>> +public class ClassReference<T> implements Serializable
>> +{
>> + private transient WeakReference<Class<? extends T>> cache;
>> + private final String name;
>> +
>> + /**
>> + * Constructor
>> + *
>> + * @param clazz
>> + */
>> + public ClassReference(Class<? extends T> clazz)
>> + {
>> + name = clazz.getName();
>> + cache(clazz);
>> + }
>> +
>> + /**
>> + * @return the {@link Class} stored in this reference
>> + */
>> + @SuppressWarnings("unchecked")
>> + public Class<? extends T> get()
>> + {
>> + Class<? extends T> clazz = cache != null ? cache.get() :
>> null;
>> + if (clazz == null)
>> + {
>> + try
>> + {
>> + clazz = (Class<? extends
>> T>)Application.get()
>> + .getApplicationSettings()
>> + .getClassResolver()
>> + .resolveClass(name);
>
>
> Issue 1:
> org.apache.wicket.core.util.lang.WicketObjects#resolveClass(String) does
> almost the same.
> Differences:
> 1) it falls back to the context class loader
> 2) it just logs a warning and returns null instead
>
> Question: do we want to re-use it here ?
done. i dont much like the idea of delegating to the context because
this class should fail outside of wicket context, but it doesnt matter
that much i guess.
> Issue 2:
> org.apache.wicket.util.ClassProvider is something very similar to
> ClassReference.
> problem 1: ClassProvider is just broken in its current state because it
> doesn't resolve the class from its name when the weakRef is null.
yes, it seems very strange and very broken.
> problem 2: Its only usage is at
> org.apache.wicket.SystemMapper.HomePageProvider and it really doesn't need
> ClassProvider but just IProvider<Class<? extends Page>>
>
> Question: should we merge ClassProvider and ClassReference into one ?
> I think the easiest way is to just deprecate ClassProvider.
i modified classreference to implement iprovider so it can now replace
classprovider as a drop in. want to do it?
-igor
>
>> + }
>> + catch (ClassNotFoundException e)
>> + {
>> + throw new RuntimeException("Could not
>> resolve class: " + name, e);
>> + }
>> + cache(clazz);
>> + }
>> + return clazz;
>> + }
>> +
>> + private void cache(Class<? extends T> clazz)
>> + {
>> + cache = new WeakReference<Class<? extends T>>(clazz);
>> + }
>> +
>> + /**
>> + * Diamond operator factory
>> + *
>> + * @param clazz
>> + * @return class reference
>> + */
>> + public static <T> ClassReference<T> of(Class<T> clazz)
>> + {
>> + return new ClassReference<T>(clazz);
>> + }
>> +}
>> \ No newline at end of file
>>
>
>
>
> --
> Martin Grigorov
> jWeekend
> Training, Consulting, Development
> http://jWeekend.com
>
