From 8e0aed0711a26fec5c0497cee9777744f1d48663 Mon Sep 17 00:00:00 2001
From: Marcin Chrzanowski <marcin.j.chrzanowski@gmail.com>
Date: Sat, 28 Dec 2019 15:47:06 +0100
Subject: Apply only fresher attributes

---
 .../edu/mimuw/cloudatlas/agent/modules/Stanik.java | 83 +++++++++++++++++++---
 1 file changed, 74 insertions(+), 9 deletions(-)

(limited to 'src/main/java/pl')

diff --git a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
index a457a94..76ca0b6 100644
--- a/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
+++ b/src/main/java/pl/edu/mimuw/cloudatlas/agent/modules/Stanik.java
@@ -1,5 +1,6 @@
 package pl.edu.mimuw.cloudatlas.agent.modules;
 
+import java.util.Iterator;
 import java.util.Map.Entry;
 
 import pl.edu.mimuw.cloudatlas.agent.messages.AgentMessage;
@@ -10,16 +11,27 @@ import pl.edu.mimuw.cloudatlas.agent.messages.UpdateAttributesMessage;
 import pl.edu.mimuw.cloudatlas.model.AttributesMap;
 import pl.edu.mimuw.cloudatlas.model.Attribute;
 import pl.edu.mimuw.cloudatlas.model.PathName;
+import pl.edu.mimuw.cloudatlas.model.Type;
+import pl.edu.mimuw.cloudatlas.model.TypePrimitive;
 import pl.edu.mimuw.cloudatlas.model.Value;
+import pl.edu.mimuw.cloudatlas.model.ValueBoolean;
 import pl.edu.mimuw.cloudatlas.model.ValueString;
+import pl.edu.mimuw.cloudatlas.model.ValueTime;
 import pl.edu.mimuw.cloudatlas.model.ZMI;
 
 public class Stanik extends Module {
+    private class InvalidUpdateAttributesMessage extends Exception {
+        public InvalidUpdateAttributesMessage(String message) {
+            super(message);
+        }
+    }
+
     private ZMI hierarchy;
 
     public Stanik() {
         super(ModuleType.STATE);
         hierarchy = new ZMI();
+        hierarchy.getAttributes().add("timestamp", new ValueTime(0l));
     }
 
     public void handleTyped(StanikMessage message) throws InterruptedException, InvalidMessageType {
@@ -42,23 +54,75 @@ public class Stanik extends Module {
 
     public void handleUpdateAttributes(UpdateAttributesMessage message) {
         try {
+            validateUpdateAttributesMessage(message);
             addMissingZones(new PathName(message.getPathName()));
             ZMI zone = hierarchy.findDescendant(message.getPathName());
-            for (Entry<Attribute, Value> entry : zone.getAttributes()) {
-                Attribute attribute = entry.getKey();
-                Value newValue = message.getAttributes().getOrNull(attribute);
-                if (newValue == null) {
-                    zone.getAttributes().remove(attribute);
-                }
-            }
-            for (Entry<Attribute, Value> entry : message.getAttributes()) {
-                zone.getAttributes().addOrChange(entry.getKey(), entry.getValue());
+            AttributesMap attributes = zone.getAttributes();
+            if (valueLower(attributes.get("timestamp"), message.getAttributes().get("timestamp"))) {
+                transferAttributes(message.getAttributes(), attributes);
+            } else {
+                System.out.println("DEBUG: not applying update with older attributes");
             }
+        } catch (InvalidUpdateAttributesMessage e) {
+            System.out.println("ERROR: invalid UpdateAttributesMessage " + e.getMessage());
         } catch (ZMI.NoSuchZoneException e) {
             System.out.println("ERROR: zone should exist after being added");
         }
     }
 
+    private boolean valueLower(Value a, Value b) {
+        return ((ValueBoolean) a.isLowerThan(b)).getValue();
+    }
+
+    private void validateUpdateAttributesMessage(UpdateAttributesMessage message) throws InvalidUpdateAttributesMessage {
+        validateZoneName(message);
+        validateHasTimeStamp(message);
+    }
+
+    private void validateZoneName(UpdateAttributesMessage message) throws InvalidUpdateAttributesMessage {
+        Value name = message.getAttributes().getOrNull("name");
+        if (message.getPathName().equals("/")) {
+            if (name != null && !name.isNull()) {
+                throw new InvalidUpdateAttributesMessage("The root zone should have a null name");
+            }
+        } else {
+            if (valueNonNullOfType(name, TypePrimitive.STRING)) {
+                ValueString nameString = (ValueString) name;
+                String expectedName = (new PathName(message.getPathName())).getSingletonName();
+                if (!nameString.getValue().equals(expectedName)) {
+                    throw new InvalidUpdateAttributesMessage("The zone's name attribute should match its path name");
+                }
+            } else {
+                throw new InvalidUpdateAttributesMessage("Zone attributes should have a name attribute of type String");
+            }
+        }
+    }
+
+    private void validateHasTimeStamp(UpdateAttributesMessage message) throws InvalidUpdateAttributesMessage {
+        if (!valueNonNullOfType(message.getAttributes().getOrNull("timestamp"), TypePrimitive.TIME)) {
+            throw new InvalidUpdateAttributesMessage("Zone attriutes should have a timestamp attribute of type Time");
+        }
+    }
+
+    private boolean valueNonNullOfType(Value value, Type type) {
+        return value != null && !value.isNull() && value.getType().isCompatible(type);
+    }
+
+    private void transferAttributes(AttributesMap fromAttributes, AttributesMap toAttributes) {
+        Iterator<Entry<Attribute, Value>> iterator = toAttributes.iterator();
+        while (iterator.hasNext()) {
+            Entry<Attribute, Value> entry = iterator.next();
+            Attribute attribute = entry.getKey();
+            Value newValue = fromAttributes.getOrNull(attribute);
+            if (newValue == null) {
+                iterator.remove();
+            }
+        }
+        for (Entry<Attribute, Value> entry : fromAttributes) {
+            toAttributes.addOrChange(entry.getKey(), entry.getValue());
+        }
+    }
+
     private void addMissingZones(PathName path) {
         try {
             if (!hierarchy.descendantExists(path)) {
@@ -66,6 +130,7 @@ public class Stanik extends Module {
                 ZMI parent = hierarchy.findDescendant(path.levelUp());
                 ZMI newSon = new ZMI(parent);
                 newSon.getAttributes().add("name", new ValueString(path.getSingletonName()));
+                newSon.getAttributes().add("timestamp", new ValueTime(0l));
                 parent.addSon(newSon);
             }
         } catch (ZMI.NoSuchZoneException e) {
-- 
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