Conditionally display a message at another page

Question

I came across an easy way to Show Apex message at another page (code is given below). I have a situation where 'Save' and 'Cancel' buttons on page 1 are going to redirect to the Page 2 and display messages according to the button's action.' The best way to include a condition for displaying the message? Thanks.

Controller 1

public PageReference GoToPage2()
{
  ApexPages.PageReference pr = new ApexPages.PageReference(Page.Page2);
  pr.SetRedirect(true);
  pr.GetParameters().Put('message', 'Hello, World!');
  return pr;
}

Page 1

<apex:commandButton action="{!GoToPage2}" value="Page 2!"/>

Controller 2

public void Init()
{
  String message = '' + ApexPages.CurrentPage().GetParameters().Get('message');
  String pageHeaderReferer = ApexPages.currentPage().getHeaders().get('Referer'); 

  // Use the referrer parameter to only show the message when coming from Page 1
  if(pageHeaderReferer != null && pageHeaderReferer.containsIgnoreCase('Page1') && message != 'null')
  {
    ApexPages.CurrentPage().AddMessage(new ApexPages.Message(ApexPages.Severity.Info, message));
  }
}

Page 2

<apex:page controller="Page2Controller" action="{!Init}">
<apex:pageMessages/>

Answer 1

Here's a simple way I would do it.... let me know if you are needing something different. Thanks!

Page:

<apex:commandButton value="Save" action="{!GoToPage2}">
   <apex:param name="action" assignTo="{!action}" value="Save"/>
</apex:commandButton>
<apex:commandButton value="Cancel" action="{!GoToPage2}">
   <apex:param name="action" assignTo="{!action}" value="Cancel"/>
</apex:commandButton>

Controller:

public String action {get; set;}
public PageReference GoToPage2()
{
  ApexPages.PageReference pr = new ApexPages.PageReference(Page.Page2);
  pr.SetRedirect(true);
  pr.GetParameters().Put('message', 'Hello, World!');
  //pass a new param to the page of action
  pr.GetParameters().Put('action', action);
  return pr;
}