From 219e6073edb2f382aea6391902f2146e3fbb9b82 Mon Sep 17 00:00:00 2001
From: Joshua Kissoon <JoshuaKissoon@gmail.com>
Date: Sat, 22 Mar 2014 15:52:37 +0530
Subject: [PATCH] Content deletion from a node that is no longer one of the
 K-Closest is working!

---
 src/kademlia/dht/DHT.java                     | 31 +++++++++++++++++++
 src/kademlia/dht/StorageEntryManager.java     | 18 +++++++++++
 .../exceptions/ContentNotFoundException.java  | 21 +++++++++++++
 .../operation/ContentRefreshOperation.java    | 17 ++++++++--
 4 files changed, 84 insertions(+), 3 deletions(-)
 create mode 100644 src/kademlia/exceptions/ContentNotFoundException.java

diff --git a/src/kademlia/dht/DHT.java b/src/kademlia/dht/DHT.java
index 7e1efdc..7fd22be 100644
--- a/src/kademlia/dht/DHT.java
+++ b/src/kademlia/dht/DHT.java
@@ -12,6 +12,7 @@ import java.util.NoSuchElementException;
 import kademlia.core.Configuration;
 import kademlia.core.GetParameter;
 import kademlia.exceptions.ContentExistException;
+import kademlia.exceptions.ContentNotFoundException;
 import kademlia.node.NodeId;
 import kademlia.serializer.JsonSerializer;
 
@@ -156,6 +157,36 @@ public class DHT
         throw new NoSuchElementException();
     }
 
+    /**
+     * Delete a content from local storage
+     *
+     * @param content The Content to Remove
+     *
+     *
+     * @throws kademlia.exceptions.ContentNotFoundException
+     */
+    public void remove(KadContent content) throws ContentNotFoundException
+    {
+        this.remove(new StorageEntry(content));
+    }
+
+    public void remove(StorageEntry entry) throws ContentNotFoundException
+    {
+        String folder = this.getContentStorageFolderName(entry.getKey());
+        File file = new File(folder + File.separator + entry.hashCode() + ".kct");
+
+        entriesManager.remove(entry);
+
+        if (file.exists())
+        {
+            file.delete();
+        }
+        else
+        {
+            throw new ContentNotFoundException();
+        }
+    }
+
     /**
      * Get the name of the folder for which a content should be stored
      *
diff --git a/src/kademlia/dht/StorageEntryManager.java b/src/kademlia/dht/StorageEntryManager.java
index 9e09924..70bec3f 100644
--- a/src/kademlia/dht/StorageEntryManager.java
+++ b/src/kademlia/dht/StorageEntryManager.java
@@ -7,6 +7,7 @@ import java.util.Map;
 import java.util.NoSuchElementException;
 import kademlia.core.GetParameter;
 import kademlia.exceptions.ContentExistException;
+import kademlia.exceptions.ContentNotFoundException;
 import kademlia.node.NodeId;
 
 /**
@@ -159,6 +160,23 @@ class StorageEntryManager
         return entriesRet;
     }
 
+    public void remove(KadContent content) throws ContentNotFoundException
+    {
+        this.remove(new StorageEntry(content));
+    }
+
+    public void remove(StorageEntry entry) throws ContentNotFoundException
+    {
+        if (contains(entry))
+        {
+            this.entries.get(entry.getKey()).remove(entry);
+        }
+        else
+        {
+            throw new ContentNotFoundException("This content does not exist in the Storage Entries");
+        }
+    }
+
     @Override
     public String toString()
     {
diff --git a/src/kademlia/exceptions/ContentNotFoundException.java b/src/kademlia/exceptions/ContentNotFoundException.java
new file mode 100644
index 0000000..4b7bf84
--- /dev/null
+++ b/src/kademlia/exceptions/ContentNotFoundException.java
@@ -0,0 +1,21 @@
+package kademlia.exceptions;
+
+/**
+ * An exception used to indicate that a content does not exist on the DHT
+ *
+ * @author Joshua Kissoon
+ * @created 20140322
+ */
+public class ContentNotFoundException extends Exception
+{
+
+    public ContentNotFoundException()
+    {
+        super();
+    }
+
+    public ContentNotFoundException(String message)
+    {
+        super(message);
+    }
+}
diff --git a/src/kademlia/operation/ContentRefreshOperation.java b/src/kademlia/operation/ContentRefreshOperation.java
index 99ff028..2302e58 100644
--- a/src/kademlia/operation/ContentRefreshOperation.java
+++ b/src/kademlia/operation/ContentRefreshOperation.java
@@ -6,6 +6,7 @@ import kademlia.core.Configuration;
 import kademlia.core.KadServer;
 import kademlia.dht.DHT;
 import kademlia.dht.StorageEntry;
+import kademlia.exceptions.ContentNotFoundException;
 import kademlia.message.Message;
 import kademlia.message.StoreContentMessage;
 import kademlia.node.Node;
@@ -69,9 +70,19 @@ public class ContentRefreshOperation implements Operation
                 }
             }
 
-            /**
-             * @todo Delete any content on this node that this node is not one of the K-Closest nodes to
-             */
+            /* Delete any content on this node that this node is not one of the K-Closest nodes to */
+            try
+            {
+                if (!closestNodes.contains(this.localNode))
+                {
+                    this.dht.remove(e);
+                }
+            }
+            catch (ContentNotFoundException cnfe)
+            {
+                /* It would be weird if the content is not found here */
+                System.err.println("ContentRefreshOperation: Removing content from local node, content not found... Message: " + cnfe.getMessage());
+            }
         }
 
     }