[jira] [Created] (WICKET-6461) Default constructor is incorrectly called if optional param is not provided in parameter placeholder URL with additional required parameter

[Melissa Beldman (JIRA)]

Melissa Beldman created WICKET-6461:
---------------------------------------

             Summary: Default constructor is incorrectly called if optional 
param is not provided in parameter placeholder URL with additional required 
parameter
                 Key: WICKET-6461
                 URL: https://issues.apache.org/jira/browse/WICKET-6461
             Project: Wicket
          Issue Type: Bug
          Components: wicket
    Affects Versions: 6.22.0
            Reporter: Melissa Beldman


>From the documentation here:

https://ci.apache.org/projects/wicket/guide/6.x/guide/urls.html

I'm following the section titled, "Using parameter placeholders with mounted 
pages".

I can't find the other documentation where I read this (but it was official 
wicket documentation) that said the order in which the optional parameter 
placeholder(s) appear doesn't matter. I've found it does matter IF other 
segments in the url are also parameter placeholders. The resulting behaviour is 
that if the optional parameter placeholder isn't provided in the URL, the 
page's default constructor gets called instead of the PageParameter constructor 
as expected (since there are still additional PageParameter data that may need 
to be processed by the page). 

Here is my example:

>From child class of AdtAuthenticatedWebApplication
{code}
@Override
protected void init() 
{
    super.init();

    mountPage("/foo/#{optParam}/${otherParam}", 
ca.example.for.testing.MyPage.class);
}
{code}

In child class of WebPage
{code}
public class MyPage extends WebPage
{
    public MyPage(PageParameters parameters) 
    {
        super(parameters);

        StringValue optParam = parameters.get("optParam");
        StringValue otherParam = parameters.get("otherParam");

       //do something...
    }

    private MyPage()
    {        
        throw new IllegalAccessError("The default constructor should not be 
instantiated");
    }
{code}

And in a different class:
{code}
public static BookmarkablePageLink getBookmarkableLink(String id, String 
optParam, String otherParam)
 {         
        PageParameters pageParam = new PageParameters();
                
        pageParam.add("otherParam", otherParam);

        if (optParam != null && !optParam.isEmpty())
        {
            pageParam.add("optParam", optParam);
        }
                
        return new BookmarkablePageLink(id, MyPage.class, pageParam);           
  
    } 
{code}

Here are the result of clicking on the BookmarkablePageLinks created:
{code}
/foo/baz/bar  -- calls MyPage(PageParameters parameters) constructor
/foo/bar -- attempts to call MyPage default constructor (exception thrown)
{code}

Exception thrown is:
{code}
Last cause: Class org.apache.wicket.session.DefaultPageFactory can not access a 
member of class ca.example.for.testing.MyPage with modifiers "private"
WicketMessage: Can't instantiate page using constructor 'private 
ca.example.for.testing.MyPage()'. This constructor is private!
{code}



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