Basic implementation for notes app

web-container-registry/src/main/java/de/nbscloud/webcontainer/MessageHelper.java

@@ -0,0 +1,43 @@
+package de.nbscloud.webcontainer;
+
+import org.springframework.stereotype.Component;
+import org.springframework.ui.Model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+public class MessageHelper {
+    // We have to temporarily store messages as we redirect: in some methods
+    // so everything we add to the model will be gone, that's why we store messages
+    // temporarily in here
+    private final List<String> errors = new ArrayList<>();
+    private final List<String> shareInfo = new ArrayList<>();
+    private final List<String> infoMessages = new ArrayList<>();
+
+    public void addAndClearAll(Model model) {
+        model.addAttribute("errors", getAndClear(this.errors));
+        model.addAttribute("infoMessages", getAndClear(this.infoMessages));
+        model.addAttribute("shareInfo", getAndClear(this.shareInfo));
+    }
+
+    private static List<String> getAndClear(List<String> source) {
+        final List<String> retList = new ArrayList<>(source);
+
+        source.clear();
+
+        return retList;
+    }
+
+    public void addError(String message) {
+        this.errors.add(message);
+    }
+
+    public void addShare(String message) {
+        this.shareInfo.add(message);
+    }
+
+    public void addInfo(String message) {
+        this.infoMessages.add(message);
+    }
+}