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https://issues.apache.org/jira/browse/WICKET-6644?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16791443#comment-16791443
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Thomas Heigl edited comment on WICKET-6644 at 3/13/19 8:42 AM:
---------------------------------------------------------------
Should I create a PR for this? Which option do you prefer? Initialize the field
to {{-1}} or change it to a {{Long}}?
This is the code in question:
{code:java}
public abstract class AbstractPageableView<T> extends RefreshingView<T>
implements IPageableItems
{
/**
* <code>cachedItemCount</code> is used to cache the call to
<code>internalGetItemCount()</code>
* for the duration of the request because that call can potentially be
expensive ( a select
* count query ) and so we do not want to execute it multiple times.
*/
private transient long cachedItemCount;
private void clearCachedItemCount()
{
cachedItemCount = -1;
}
private void setCachedItemCount(long itemCount)
{
cachedItemCount = itemCount;
}
private long getCachedItemCount()
{
if (cachedItemCount < 0)
{
throw new IllegalStateException("getItemCountCache() called when cache was
not set");
}
return cachedItemCount;
}
private boolean isItemCountCached()
{
return cachedItemCount >= 0;
}
private void readObject(java.io.ObjectInputStream s) throws
java.io.IOException, ClassNotFoundException
{
// Read in all fields
s.defaultReadObject();
clearCachedItemCount();
}
}{code}
was (Author: thomas.heigl):
Should I create a PR for this? Which option do you prefer? Initialize the field
to {{-1}} or change it to a {{Long}}?
This is the code in question:
{code:java}
public abstract class AbstractPageableView<T> extends RefreshingView<T>
implements IPageableItems
{
/**
* <code>cachedItemCount</code> is used to cache the call to
<code>internalGetItemCount()</code>
* for the duration of the request because that call can potentially be
expensive ( a select
* count query ) and so we do not want to execute it multiple times.
*/
private transient long cachedItemCount;
private void clearCachedItemCount()
{
cachedItemCount = -1;
}
private void readObject(java.io.ObjectInputStream s) throws
java.io.IOException, ClassNotFoundException
{
// Read in all fields
s.defaultReadObject();
clearCachedItemCount();
}
}{code}
> AbstractPageableView can only be serialized with Java built-in serialization
> ----------------------------------------------------------------------------
>
> Key: WICKET-6644
> URL: https://issues.apache.org/jira/browse/WICKET-6644
> Project: Wicket
> Issue Type: Improvement
> Components: wicket-core
> Affects Versions: 8.3.0
> Reporter: Thomas Heigl
> Priority: Major
>
> I'm in the progress of replacing FST serialization, that we have used in
> production for years, with Kryo.
> FST is a drop-in replacement for Java's built-in serialization and respects
> the {{readObject/writeObject}} contract. Kryo does not rely on Java
> serialization at all.
> All of Wicket's classes can be serialized with recent versions of Kryo
> without problems, but when I did some exploratory testing, I noticed that all
> our pageable lists were empty after deserialization.
> After some investigation, I found the root cause of this: WICKET-1323
> {{AbstractPageableView}} is the *only* class in Wicket that relies a custom
> {{readObject}} method to correctly restore its state.
> I propose to get rid of this method and simply initialize the transient field
> to a default value of {{-1}} or use a {{Long}} instead of a {{long}} to
> represent the cached item count.
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