Struts 2 Conversation Scope Plugin with no @EndConversation

Question

Consider below example, which I think is a very common sample of step forms. I have a three step form which want to transfer money from an account to other :

First  page gets user source account
Second page shows source account and gets destination account and the amount
Last   page shows a confirmation which mention source account + destination account + amount

As you can see I need the model information in the last page too. So I use @BeginConversation for first action and @ConversationAction for second and last page.

The question is none of my actions are annotated with @EndConversation. Is it OK?! Will the model resides in memory or it will be auto cleaned? I could not find when it is auto cleaned.

Answer 1

I had the similar problem. If my end action was called through a form submit I was always getting an error saying that the conversation was already closed or expired.

Of course if you don't finish the conversation, memory resources won't be released. You can get some information about this in the strut2 conversation plugin site: https://code.google.com/p/struts2-conversation/wiki/UsageGuide#Memory_Management

There you can see that it is possible to set some parameters related with the expiration of the conversation thread and the number of them that can be used at the same time:

<!-- monitoring frequency in milliseconds -->
<constant name="conversation.monitoring.frequency" value="300000"/>

<!-- idle conversation timeout in milliseconds -->
<constant name="conversation.idle.timeout" value="28800000"/>

<!-- max instances of a conversation -->
<constant name="conversation.max.instances" value="20"/>

<!-- number of timeout monitoring threads -->
<constant name="conversation.monitoring.thread.pool.size" value="20"/>

Anyway, I resolved this issue adding a redirect result in the last action which calls to an action which contains the @EndConversation tag. In it I just set the result I wanted to be the last one. The conversation fields variables are still correct set and available.

@ConversationAction(conversations = "form")
@Action(value="formSecondLast", results={@Result(name=SUCCESS, type = "redirect", location="formLast")})
public String formSecondLast() throws Exception {
    //Here goes the code you want it to manipulate the conversation field data.
    //Maybe save to the database or send it to the business tier.
    return SUCCESS;
}

@EndConversation(conversations = "form")
@Action(value="formLast", results={@Result(name=SUCCESS, location="/jsp/form-end.jsp")})
public String formEnd() throws Exception {
    // This is a dummy action that does not do anything.
    // It is called just after formSecondLast ends and sends the user the jsp page.
    return SUCCESS;
}