rewrite basket to use spring SessionAttributes

src/main/java/info/textgrid/rep/basket/Basket.java

+package info.textgrid.rep.basket;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Basket {
+
+  private List<String> items = new ArrayList<String>();
+
+  public List<String> getItems() {
+    return items;
+  }
+
+  public int addItem(String item) {
+    items.add(item);
+    return items.size();
+  }
+
+  public long remove(String textgridUri) {
+    items.remove(textgridUri);
+    return items.size();
+  }
+
+  public String getItemsAsString() {
+    return String.join(",", items);
+  }
+
+  public long clear() {
+    items.clear();
+    return items.size();
+  }
+
+  public long size() {
+    return items.size();
+  }
+
+  public boolean contains(String textgridUri) {
+    return items.contains(textgridUri);
+  }
+
+
+}

src/main/java/info/textgrid/rep/basket/BasketAjaxController.java

 package info.textgrid.rep.basket;
 
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-import javax.servlet.http.HttpSession;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.SessionAttributes;
 
 
 @RestController
+@SessionAttributes("basket")
 @RequestMapping("/service/shelf")
 public class BasketAjaxController {
 
+  @ModelAttribute("basket")
+  public Basket getBasket() {
+      return new Basket();
+  }
+
   @PostMapping("/add")
-  public long addToBasket(
-      HttpSession session,
+  public int addToBasket(
+      @ModelAttribute Basket basket,
       @RequestParam("uri") String textgridUri
       ) throws IOException {
 
-    List<String> basket;
+    return basket.addItem(textgridUri);
 
-    if(session.getAttribute("basket") == null) {
-      basket = new ArrayList<String>();
-    } else {
-      basket = (List<String>) session.getAttribute("basket");
-    }
-    basket.add(textgridUri);
-    session.setAttribute("basket", basket);
-    return basket.size();
   }
 
-
   @PostMapping("/remove")
   public long removeFromBasket(
-      HttpSession session,
+      @ModelAttribute Basket basket,
       @RequestParam("uri") String textgridUri
       ) throws IOException {
 
-    List<String> basket = (List<String>) session.getAttribute("basket");
-    basket.remove(textgridUri);
-    session.setAttribute("basket", basket);
-    return basket.size();
+    return basket.remove(textgridUri);
+
   }
 
   @PostMapping("/clear")
-  public long clearBasket(
-      HttpSession session
-      ) throws IOException {
-
-    session.setAttribute("basket", new ArrayList<String>());
-
-    return basketCount(session);
+  public long clearBasket(@ModelAttribute Basket basket) {
+    return basket.clear();
   }
 
   @GetMapping("/count")
-  public long basketCount(HttpSession session) {
-
-    long count;
-
-    if (session.getAttribute("basket")== null) {
-      count = 0;
-    } else {
-      count = ((List<String>) session.getAttribute("basket")).size();
-    }
-   return count;
-
+  public long basketCount(@ModelAttribute Basket basket) {
+    return basket.size();
   }
 
-
-
 }

src/main/java/info/textgrid/rep/basket/BasketController.java

@@ -3,44 +3,47 @@ package info.textgrid.rep.basket;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
-import javax.servlet.http.HttpSession;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.SessionAttributes;
 import info.textgrid.namespaces.middleware.tgsearch.ResultType;
 import info.textgrid.rep.i18n.I18N;
 import info.textgrid.rep.i18n.I18NProvider;
 import info.textgrid.rep.service.tgsearch.TgrepConfigurationService;
 import info.textgrid.rep.service.tgsearch.TgsearchClientService;
-import info.textgrid.rep.shared.Utils;
 import info.textgrid.rep.shared.ViewMode;
 
 @Controller
+@SessionAttributes("basket")
 public class BasketController {
 
-
+  @Autowired
   private TgsearchClientService tgsearchClientService;
 
+  @Autowired
   private TgrepConfigurationService tgrepConfig;
+
+  @Autowired
   private I18NProvider i18nProvider;
+
   private static final Log log = LogFactory.getLog(BasketController.class);
 
-  @Autowired
-  public BasketController(TgsearchClientService tgsearchClientService, TgrepConfigurationService tgrepConfig, I18NProvider i18nProvider) {
-    this.tgsearchClientService = tgsearchClientService;
-    this.tgrepConfig = tgrepConfig;
-    this.i18nProvider = i18nProvider;
+  @ModelAttribute("basket")
+  public Basket getBasket() {
+      return new Basket();
   }
 
   @GetMapping("/shelf")
   public String render(
       Model model,
       Locale locale,
-      HttpSession session,
+      @ModelAttribute Basket basket,
       @RequestParam(value="mode", required=false) String mode) {
 
     I18N i18n = i18nProvider.getI18N(locale);
@@ -49,10 +52,8 @@ public class BasketController {
 
     List<ResultType> results = new ArrayList<ResultType>();
 
-    List<String> basket = (List<String>) session.getAttribute("basket");
-
     if(basket != null) {
-        for(String textgridUri : basket) {
+        for(String textgridUri : basket.getItems()) {
             ResultType res = tgsearchClientService.getMetadata(textgridUri);
             results.add(res);
         }
@@ -66,7 +67,7 @@ public class BasketController {
     model.addAttribute("results", results);
     model.addAttribute("aggregatorUrl", tgrepConfig.getTextgridHost()+"/1.0/aggregator");
     model.addAttribute("voyantUrl", tgrepConfig.getToolVoyantHost());
-    model.addAttribute("basketItemString", Utils.getBasketItemsAsString(session));
+    model.addAttribute("basketItemString", basket.getItemsAsString());
     model.addAttribute("textgridHost", this.tgrepConfig.getTextgridHost());
 
     // translation array

src/main/java/info/textgrid/rep/shared/Utils.java

@@ -3,8 +3,6 @@ package info.textgrid.rep.shared;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.util.List;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpSession;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.w3._1999._02._22_rdf_syntax_ns_.RdfType;
@@ -12,9 +10,6 @@ import org.w3c.dom.Element;
 import info.textgrid.namespaces.metadata.core._2010.RelationType;
 import info.textgrid.namespaces.middleware.tgsearch.ResultType;
 
-
-
-
 public class Utils {
 
 	private final static int THUMBSIZE = 250;
@@ -92,19 +87,6 @@ public class Utils {
 		return sb.toString();
 	}
 
-
-	public static List<String> getBasketItems(HttpSession session) {
-		return (List<String>) session.getAttribute("basket");
-	}
-
-	public static String getBasketItemsAsString(HttpSession session) {
-	    String itemstring = "";
-	    if(getBasketItems(session) != null) {
-	      itemstring = String.join(",", getBasketItems(session));
-	    }
-	    return itemstring;
-	}
-
 	public static String urlencode(String string) {
 		try {
 			string = URLEncoder.encode(string, "UTF-8");