From f0bf6927674a8c4fdf5a74352749ca5be326b5d3 Mon Sep 17 00:00:00 2001
From: michaelisvy <misvy@gopivotal,com>
Date: Fri, 28 Nov 2014 13:19:25 +0900
Subject: [PATCH] Moving "visit" object to request scope
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Previously was in session scope (doesn’t scale as well)
---
 .../petclinic/web/VisitController.java        | 40 ++++++++++++-------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/src/main/java/org/springframework/samples/petclinic/web/VisitController.java b/src/main/java/org/springframework/samples/petclinic/web/VisitController.java
index 4f38bd574..f3f6f3ffb 100644
--- a/src/main/java/org/springframework/samples/petclinic/web/VisitController.java
+++ b/src/main/java/org/springframework/samples/petclinic/web/VisitController.java
@@ -27,12 +27,10 @@ import org.springframework.stereotype.Controller;
 import org.springframework.validation.BindingResult;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.InitBinder;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
-import org.springframework.web.bind.annotation.SessionAttributes;
-import org.springframework.web.bind.support.SessionStatus;
-import org.springframework.web.servlet.ModelAndView;
 
 /**
  * @author Juergen Hoeller
@@ -41,7 +39,6 @@ import org.springframework.web.servlet.ModelAndView;
  * @author Michael Isvy
  */
 @Controller
-@SessionAttributes("visit")
 public class VisitController {
 
     private final ClinicService clinicService;
@@ -56,32 +53,45 @@ public class VisitController {
     public void setAllowedFields(WebDataBinder dataBinder) {
         dataBinder.setDisallowedFields("id");
     }
-
-    @RequestMapping(value = "/owners/*/pets/{petId}/visits/new", method = RequestMethod.GET)
-    public String initNewVisitForm(@PathVariable("petId") int petId, Map<String, Object> model) {
+    
+    /**
+     *  Called before each and every @RequestMapping annotated method.
+     *  2 goals:
+     *  - Make sure we always have fresh data
+     *  - Since we do not use the session scope, make sure that Pet object always has an id 
+     *    (Even though id is not part of the form fields)
+     * @param petId
+     * @return Pet
+     */
+    @ModelAttribute("visit")
+    public Visit loadPetWithVisit(@PathVariable("petId") int petId) {
         Pet pet = this.clinicService.findPetById(petId);
         Visit visit = new Visit();
-        pet.addVisit(visit);
-        model.put("visit", visit);
+        pet.addVisit(visit);  
+        return visit;
+    }
+
+	// Spring MVC calls method loadPetWithVisit(...) before initNewVisitForm is called
+    @RequestMapping(value = "/owners/*/pets/{petId}/visits/new", method = RequestMethod.GET)
+    public String initNewVisitForm(@PathVariable("petId") int petId, Map<String, Object> model) {
         return "pets/createOrUpdateVisitForm";
     }
 
+	// Spring MVC calls method loadPetWithVisit(...) before processNewVisitForm is called
     @RequestMapping(value = "/owners/{ownerId}/pets/{petId}/visits/new", method = RequestMethod.POST)
-    public String processNewVisitForm(@Valid Visit visit, BindingResult result, SessionStatus status) {
+    public String processNewVisitForm(@Valid Visit visit, BindingResult result) {
         if (result.hasErrors()) {
             return "pets/createOrUpdateVisitForm";
         } else {
             this.clinicService.saveVisit(visit);
-            status.setComplete();
             return "redirect:/owners/{ownerId}";
         }
     }
 
     @RequestMapping(value = "/owners/*/pets/{petId}/visits", method = RequestMethod.GET)
-    public ModelAndView showVisits(@PathVariable int petId) {
-        ModelAndView mav = new ModelAndView("visitList");
-        mav.addObject("visits", this.clinicService.findPetById(petId).getVisits());
-        return mav;
+    public String showVisits(@PathVariable int petId, Map<String, Object> model) {
+        model.put("visits", this.clinicService.findPetById(petId).getVisits());
+        return "visitList";
     }
 
 }