Github user martin-g commented on a diff in the pull request:
https://github.com/apache/wicket/pull/210#discussion_r99945295
--- Diff:
wicket-core/src/main/java/org/apache/wicket/core/request/handler/PageProvider.java
---
@@ -388,49 +350,95 @@ public Integer getRenderCount()
return renderCount;
}
- /**
- * Checks whether or not the provider has a page instance. This page
instance might have been
- * passed to this page provider directly or it may have been
instantiated or retrieved from the
- * page store.
- *
- * @return {@code true} iff page instance has been created or retrieved
- */
@Override
- public final boolean hasPageInstance()
+ public String toString()
{
- if (pageInstance == null && pageId != null)
- {
- // attempt to load a stored page instance from the page
store
- getStoredPage(pageId);
- }
- return pageInstance != null;
+ return "PageProvider{" + "renderCount=" + renderCount + ",
pageId=" + pageId
+ + ", pageClass=" + pageClass + ", pageParameters=" +
pageParameters + '}';
}
/**
- * Returns whether or not the page instance held by this provider has
been instantiated by the
- * provider.
+ * A provision is the work necessary to provide a page. It includes to
resolve parameters to a
+ * page, to track the resolution metadata and to keep a reference of
the resolved page.
*
- * @throws IllegalStateException
- * if this method is called and the provider does not yet
have a page instance, ie
- * if {@link #getPageInstance()} has never been called on
this provider
- * @return {@code true} iff the page instance held by this provider was
instantiated by the
- * provider
+ * The logic based on {@link PageProvider}'s parameters:
+ *
+ * - having an stored page id, the stored page is provided
+ *
+ * - having only a page class, a new instance of it is provided
+ *
+ * - having non stored page id plus page class, a new instance of the
page class is provided
+ *
+ * - having non stored page id and no page class, no page is provided
+ *
+ * - being a page instance, the instance itself will be the provided
page
+ *
+ * @author pedro
*/
- @Override
- public final boolean isPageInstanceFresh()
+ private class Provision
{
- if (!hasPageInstance())
+ transient IRequestablePage page;
+ boolean failedToFindStoredPage;
+
+ IRequestablePage getPage()
{
- throw new IllegalStateException("Page instance not yet
resolved");
+ if (page == null && doesProvideNewPage())
+
+ page =
getPageSource().newPageInstance(pageClass, pageParameters);
+
+ return page;
+ }
+
+ boolean didResolveToPage()
+ {
+ return page != null;
+ }
+
+ boolean doesProvideNewPage()
+ {
+ return (pageId == null || failedToFindStoredPage) &&
pageClass != null;
+ }
+
+ boolean didFailToFindStoredPage()
+ {
+ return failedToFindStoredPage;
+ }
+
+ Provision resolveTo(IRequestablePage page)
+ {
+ this.page = page;
+
+ return this;
+ }
+
+ Provision resolve()
+ {
+
+ if (pageId != null)
+ {
+ IRequestablePage stored =
getPageSource().getPageInstance(pageId);
+ if (stored != null && (pageClass == null ||
pageClass.equals(stored.getClass())))
+ {
+
+ page = stored;
+
+ if (renderCount != null &&
page.getRenderCount() != renderCount)
+ throw new
StalePageException(page);
+ }
+
+ failedToFindStoredPage = page == null;
+ }
+
+ return this;
+ }
+
+ void detach()
+ {
+ if (page != null)
--- End diff --
Well, if the old code detached it then let's keep it.
There is an open ticket in JIRA that sometimes a Page is detached twice in
the same request cycle, that's why I've asked.
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