From 439cc54c71a053fdeaad6f03dbc04a1e588bfae1 Mon Sep 17 00:00:00 2001
From: Daniel Lucas <dl3g19@soton.ac.uk>
Date: Mon, 3 May 2021 18:46:46 +0100
Subject: [PATCH] More changes to adjust for MORE late changes to the spec
---
Controller.java | 172 +++++++++-------------
Dstore.java | 24 ++-
DstoreConnection.java | 43 ++++--
DstoreDisconnectException.java | 16 +-
to_store/{Look Away.mp3 => Look_Away.mp3} | Bin
5 files changed, 128 insertions(+), 127 deletions(-)
rename to_store/{Look Away.mp3 => Look_Away.mp3} (100%)
diff --git a/Controller.java b/Controller.java
index 9de796f..48b137a 100644
--- a/Controller.java
+++ b/Controller.java
@@ -8,6 +8,8 @@ import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
+import java.util.Set;
+import java.util.HashSet;
import java.util.Collection;
import java.util.Collections;
@@ -199,6 +201,7 @@ public class Controller {
}
while(clientMessage != null);
System.out.println("Client closed");
+ loadRequests.remove(client);
try {client.close();} catch(IOException e) {}
}
}).start();
@@ -335,7 +338,7 @@ public class Controller {
entry.setNumberToStore(rFactor);
//Send STORE_TO message
- CyclicBarrier barrier = new CyclicBarrier(rFactor + 1);
+ CountDownLatch latch = new CountDownLatch(rFactor);
PrintWriter out = new PrintWriter(client.getOutputStream());
String message = Protocol.STORE_TO_TOKEN;
for(Integer thisStore : storesToStore) {
@@ -345,7 +348,7 @@ public class Controller {
String[] receivedMessage = dstores.get(thisStore).receive(Protocol.STORE_ACK_TOKEN).split(" ");
if(receivedMessage[0].equals(Protocol.STORE_ACK_TOKEN)) {
try {
- storeAck(thisStore, receivedMessage[1], barrier);
+ storeAck(thisStore, receivedMessage[1], latch);
}
catch(Exception e) {
//Log error
@@ -359,7 +362,7 @@ public class Controller {
}
catch(DstoreDisconnectException e) {
e.printStackTrace();
- removeDstore(thisStore);
+ removeDstore(e);
}
}).start();
}
@@ -367,46 +370,31 @@ public class Controller {
out.flush();
//Wait for STORE_ACKs from datastores in storesToStore
- try {
- barrier.await(timeout, TimeUnit.MILLISECONDS);
+ if(latch.await(timeout, TimeUnit.MILLISECONDS)) {
+ //Update index to "store complete"
+ entry.setStatus(IndexEntry.Status.STORE_COMPLETE);
+
+ //Send STORE_COMPLETE message
+ out.println(Protocol.STORE_COMPLETE_TOKEN);
+ out.flush();
+ messageSent(client, Protocol.STORE_COMPLETE_TOKEN);
}
- catch(TimeoutException e) {
+ else {
//Log error
System.err.println("Not all STORE_ACKs have been received");
- }
- catch(Exception e) {
- e.printStackTrace();
- }
- /*
- synchronized(entry) {
- try {
- entry.wait(timeout);
- }
- catch(InterruptedException e) {
- e.printStackTrace();
- }
- if(entry.getStoredBy().size() < rFactor) {
- //Log error
- System.out.println("Not all STORE_ACKs have been received");
+ //Remove file from index
+ synchronized(index) {
+ index.remove(filename);
}
}
- */
-
- //Update index to "store complete"
- entry.status = IndexEntry.Status.STORE_COMPLETE;
-
- //Send STORE_COMPLETE message
- out.println(Protocol.STORE_COMPLETE_TOKEN);
- out.flush();
- messageSent(client, Protocol.STORE_COMPLETE_TOKEN);
}
catch(IOException e) {
e.printStackTrace();
}
}
- void storeAck(Integer port, String filename, CyclicBarrier barrier) throws Exception {
+ void storeAck(Integer port, String filename, CountDownLatch latch) throws Exception {
if(!index.containsKey(filename)) {
//Throw logging exception
throw new Exception("Index does not contain " + filename);
@@ -414,18 +402,12 @@ public class Controller {
IndexEntry thisEntry = index.get(filename);
thisEntry.addStoredBy(port);
- try {
- barrier.await();
- }
- catch(BrokenBarrierException e) {
- System.err.println("Late STORE_ACK received from " + port + " after timeout expired");
- }
- catch(Exception e) {e.printStackTrace();}
+ latch.countDown();
}
void load(Socket client, String filename) throws Exception {
try {
- if(!index.containsKey(filename) || index.get(filename).status != IndexEntry.Status.STORE_COMPLETE) {
+ if(!index.containsKey(filename) || index.get(filename).getStatus() != IndexEntry.Status.STORE_COMPLETE) {
PrintWriter out = new PrintWriter(client.getOutputStream());
out.println(Protocol.ERROR_FILE_DOES_NOT_EXIST_TOKEN);
out.flush();
@@ -478,7 +460,7 @@ public class Controller {
void remove(Socket client, String filename) throws Exception {
try {
- if(!index.containsKey(filename) || index.get(filename).status != IndexEntry.Status.STORE_COMPLETE) {
+ if(!index.containsKey(filename) || index.get(filename).getStatus() != IndexEntry.Status.STORE_COMPLETE) {
PrintWriter clientOut = new PrintWriter(client.getOutputStream());
clientOut.println(Protocol.ERROR_FILE_DOES_NOT_EXIST_TOKEN);
clientOut.flush();
@@ -488,23 +470,17 @@ public class Controller {
//Update index to "remove in progress"
IndexEntry entry = index.get(filename);
- entry.status = IndexEntry.Status.REMOVE_IN_PROGRESS;
+ entry.setStatus(IndexEntry.Status.REMOVE_IN_PROGRESS);
//Send REMOVE message to all Dstores storing the file
- CyclicBarrier barrier = new CyclicBarrier(entry.getStoredBy().size() + 1);
+ CountDownLatch latch = new CountDownLatch(entry.getStoredBy().size());
for(Integer dstore : entry.getStoredBy()) {
new Thread(() -> {
try {
String[] message = dstores.get(dstore).sendAndReceive(Protocol.REMOVE_TOKEN + " " + filename, Protocol.REMOVE_ACK_TOKEN).split(" ");
if(message[0].equals(Protocol.REMOVE_ACK_TOKEN) && message[1].equals(filename)) {
entry.removeStoredBy(dstore.intValue());
- try {
- barrier.await();
- }
- catch(BrokenBarrierException e) {
- System.err.println("Late REMOVE_ACK received from " + dstore + " after timeout expired");
- }
- catch(Exception e) {e.printStackTrace();}
+ latch.countDown();
}
else {
//Log error
@@ -513,39 +489,19 @@ public class Controller {
}
catch(DstoreDisconnectException e) {
e.printStackTrace();
- removeDstore(dstore);
+ removeDstore(e);
}
}).start();
}
//Wait for REMOVE_ACKs from all Dstores which were sent the REMOVE message
- try {
- barrier.await(timeout, TimeUnit.MILLISECONDS);
- }
- catch(TimeoutException e) {
- //Log error
- System.out.println("Not all REMOVE_ACKs have been received");
- }
- catch(Exception e) {e.printStackTrace();}
- /*
- synchronized(entry) {
- try {
- entry.wait(timeout);
- }
- catch(InterruptedException e) {
- e.printStackTrace();
- }
- }
-
-
- if(entry.getStoredBy().size() > 0) {
+ if(!latch.await(timeout, TimeUnit.MILLISECONDS)) {
//Log error
System.out.println("Not all REMOVE_ACKs have been received");
}
- */
//Update index to "remove complete"
- entry.status = IndexEntry.Status.REMOVE_COMPLETE;
+ entry.setStatus(IndexEntry.Status.REMOVE_COMPLETE);
synchronized(index) {
if(index.get(filename) == entry) index.remove(filename);
}
@@ -567,7 +523,7 @@ public class Controller {
//Send file list to client
String message = Protocol.LIST_TOKEN + " ";
for(String name : index.keySet()) {
- if(index.get(name).status == IndexEntry.Status.STORE_COMPLETE) message = message + name + " ";
+ if(index.get(name).getStatus() == IndexEntry.Status.STORE_COMPLETE) message = message + name + " ";
}
PrintWriter out = new PrintWriter(client.getOutputStream());
System.out.println("Sending...");
@@ -588,28 +544,32 @@ public class Controller {
if(rebalanceMessages.dstoreFiles != null) return;
rebalanceMessages.dstoreFiles = dstoreFiles;
}
- CyclicBarrier barrier = new CyclicBarrier(dstores.size() + 1);
+ CountDownLatch listLatch = new CountDownLatch(dstores.size());
try {
//Send LIST message to each Dstore and receive their file list
for(Integer dstore : dstores.keySet()) {
new Thread(() -> {
try {
String[] message = dstores.get(dstore).sendAndReceive(Protocol.LIST_TOKEN).split(" ");
- receiveDstoreList(dstore.intValue(), message, barrier);
+ receiveDstoreList(dstore.intValue(), message, listLatch);
}
catch(DstoreDisconnectException e) {
e.printStackTrace();
- removeDstore(dstore);
+ removeDstore(e);
}
}).start();
}
try {
- barrier.await(timeout, TimeUnit.MILLISECONDS);
- }
- catch(TimeoutException e) {
- //Log error
- System.out.println("Not all file lists have been received");
+ if(!listLatch.await(timeout, TimeUnit.MILLISECONDS)) {
+ //Log error
+ System.err.println("Not all file lists have been received");
+ Set<Integer> storesToRemove = new HashSet<Integer>(dstores.keySet());
+ storesToRemove.removeAll(dstoreFiles.keySet());
+ for(Integer dstore : storesToRemove) {
+ removeDstore(dstores.get(dstore).getDisconnectData());
+ }
+ }
}
catch(Exception e) {e.printStackTrace();}
@@ -674,7 +634,7 @@ public class Controller {
}
//For each dstore, compile a new message based on the contents of the indexes then send this message and receive a reply
- CyclicBarrier barrier2 = new CyclicBarrier(dstoreFiles.size() + 1);
+ CountDownLatch latch = new CountDownLatch(dstoreFiles.size());
for(Integer thisStore : dstoreFiles.keySet()) {
//Compose files to send
List<String> sendMessages = new ArrayList<String>();
@@ -701,13 +661,20 @@ public class Controller {
sendMessages.add(fileMessage);
}
+ //Don't need to send a rebalance message if there is nothing to update
+ List<String> thisRemove = removeIndex.get(thisStore);
+ if(sendMessages.isEmpty() && thisRemove.isEmpty()) {
+ latch.countDown();
+ return;
+ }
+
String message = Protocol.REBALANCE_TOKEN + " " + sendMessages.size();
for(String s : sendMessages) {
message = message + " " + s;
}
//Compose files to remove
- message = message + " " + removeIndex.get(thisStore).size();
- for(String f : removeIndex.get(thisStore)) {
+ message = message + " " + thisRemove.size();
+ for(String f : thisRemove) {
message = message + " " + f;
}
@@ -722,7 +689,7 @@ public class Controller {
System.out.println("Dstore " + thisStore + " should have sent REBALANCE_COMPLETE but Controller received " + returnMessage);
}
- new Thread(() -> {try {barrier2.await();} catch(Exception e) {e.printStackTrace();}}).start();
+ try {latch.countDown();} catch(Exception e) {e.printStackTrace();}
for(int i=0; i<requireIndex.get(thisStore).size(); i++) {
returnMessage = connection.receive(Protocol.STORE_ACK_TOKEN);
@@ -734,19 +701,18 @@ public class Controller {
}
catch(DstoreDisconnectException e) {
e.printStackTrace();
- removeDstore(thisStore);
+ removeDstore(e);
}
}).start();
}
//Wait for REBALANCE_COMPLETE from all Dstores
try {
- barrier2.await(timeout, TimeUnit.MILLISECONDS);
- }
- catch(TimeoutException e) {
- //Restart rebalance operation
- System.err.println("Not all REBALANCE_COMPLETEs received. Restarting rebalance operation...");
- success = false;
+ if(!latch.await(timeout, TimeUnit.MILLISECONDS)) {
+ //Restart rebalance operation
+ System.err.println("Not all REBALANCE_COMPLETEs received. Restarting rebalance operation...");
+ success = false;
+ }
}
catch(Exception e) {e.printStackTrace();}
/*
@@ -801,7 +767,7 @@ public class Controller {
if(!success) rebalance();
}
- void receiveDstoreList(int port, String[] list, CyclicBarrier barrier) {
+ void receiveDstoreList(int port, String[] list, CountDownLatch latch) {
List<String> toList = new ArrayList<String>();
if(!list[0].equals("ERROR_EMPTY")) {
for(String file : list) {
@@ -815,20 +781,18 @@ public class Controller {
rebalanceMessages.dstoreFiles.put(port, toList);
}
- try {
- barrier.await();
- }
- catch(BrokenBarrierException e) {
- System.err.println("Late file list received from " + port + " after timeout expired");
- }
- catch(Exception e) {e.printStackTrace();}
+ latch.countDown();
}
- void removeDstore(Integer dstore) {
- dstores.remove(dstore);
- Iterator<IndexEntry> it = index.values().iterator();
+ void removeDstore(DstoreDisconnectException e) {
+ Integer port = e.getPort();
+ dstores.remove(port);
+ try {e.getSocket().close();} catch(IOException ee) {}
+
+ Iterator<IndexEntry> it;
+ synchronized(index) {it = index.values().iterator();}
while(it.hasNext()) {
- it.next().removeStoredBy(dstore);
+ it.next().removeStoredBy(port);
}
}
diff --git a/Dstore.java b/Dstore.java
index 6ac0414..9bd7979 100644
--- a/Dstore.java
+++ b/Dstore.java
@@ -7,7 +7,7 @@ import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
-import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
public class Dstore {
@@ -118,19 +118,19 @@ public class Dstore {
}
void handleMessage(String[] message, Socket client) throws Exception {
- if(message[0].equals("STORE")) {
+ if(message[0].equals(Protocol.STORE_TOKEN) || message[0].equals(Protocol.REBALANCE_STORE_TOKEN)) {
store(client, message[1], Long.parseLong(message[2]));
}
- else if(message[0].equals("LOAD_DATA")) {
+ else if(message[0].equals(Protocol.LOAD_DATA_TOKEN)) {
load(client, message[1]);
}
- else if(message[0].equals("REMOVE")) {
+ else if(message[0].equals(Protocol.REMOVE_TOKEN)) {
remove(message[1]);
}
- else if(message[0].equals("LIST")) {
+ else if(message[0].equals(Protocol.LIST_TOKEN)) {
list();
}
- else if(message[0].equals("REBALANCE")) {
+ else if(message[0].equals(Protocol.REBALANCE_TOKEN)) {
rebalance(message);
}
else {
@@ -206,7 +206,7 @@ public class Dstore {
e.printStackTrace();
}
finally {
- try {client.close();} catch(IOException e) {e.printStackTrace();}
+ try {if(!client.isClosed()) client.close();} catch(IOException e) {e.printStackTrace();}
}
}).start();
}
@@ -222,7 +222,6 @@ public class Dstore {
//Send REMOVE_ACK message to client (the controller)
synchronized(controllerOut) {
controllerMessage = Protocol.REMOVE_ACK_TOKEN + " " + filename;
-
}
}
else {
@@ -300,7 +299,7 @@ public class Dstore {
System.out.println("Interpreting complete, will send " + numberToSend + " and remove " + numberToRemove);
//Send each file to send to the Dstore at the specified port number
- CyclicBarrier barrier = new CyclicBarrier(totalReceivers + 1);
+ CountDownLatch latch = new CountDownLatch(totalReceivers);
for(Integer dstore : filesToSend.keySet()) {
for(String filename : filesToSend.get(dstore)) {
new Thread(() -> {
@@ -308,7 +307,7 @@ public class Dstore {
System.out.println("Sending " + filename + " to store " + dstore);
Socket socket = new Socket(InetAddress.getLocalHost(), dstore.intValue());
PrintWriter out = new PrintWriter(socket.getOutputStream());
- String dstoreMessage = Protocol.STORE_TOKEN + " " + filename + " " + fileSizes.get(filename);
+ String dstoreMessage = Protocol.REBALANCE_STORE_TOKEN + " " + filename + " " + fileSizes.get(filename);
out.println(dstoreMessage);
out.flush();
messageSent(socket, dstoreMessage);
@@ -338,12 +337,12 @@ public class Dstore {
e.printStackTrace();
}
finally {
- try {barrier.await();} catch(Exception e) {}
+ try {latch.countDown();} catch(Exception e) {}
}
}).start();
}
}
- try {barrier.await((long) timeout, TimeUnit.MILLISECONDS);} catch(Exception e) {e.printStackTrace();}
+ try {latch.await(timeout, TimeUnit.MILLISECONDS);} catch(Exception e) {e.printStackTrace();}
//Remove each file to remove from fileFolder
for(String filename : filesToRemove) {
@@ -358,7 +357,6 @@ public class Dstore {
messageSent(controllerSocket, Protocol.REBALANCE_COMPLETE_TOKEN);
}
System.out.println("Sent message REBALANCE_COMPLETE");
- //TO DO: WAIT FOR RESPONSES BEFORE SENDING REBALANCE_COMPLETE
}).start();
}
diff --git a/DstoreConnection.java b/DstoreConnection.java
index d402186..3f82995 100644
--- a/DstoreConnection.java
+++ b/DstoreConnection.java
@@ -6,12 +6,13 @@ import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
import java.util.Collection;
+import java.util.Iterator;
public class DstoreConnection {
protected final int MAX_QUEUE_SIZE = 50;
protected Socket socket;
- protected int port; //Solely used for debugging purposes
+ protected int port;
protected BufferedReader reader;
protected PrintWriter writer;
protected boolean available;
@@ -28,7 +29,7 @@ public class DstoreConnection {
writer = new PrintWriter(socket.getOutputStream());
available = true;
queue = new ArrayList<String>();
- disconnectException = new DstoreDisconnectException(port);
+ disconnectException = new DstoreDisconnectException(port, socket);
}
catch(IOException e) {
e.printStackTrace();
@@ -40,6 +41,10 @@ public class DstoreConnection {
}
}
+ public DstoreDisconnectException getDisconnectData() {
+ return disconnectException;
+ }
+
public String sendAndReceive(String message, String expectedMessage) throws DstoreDisconnectException {
System.out.println("Getting lock...");
synchronized(this) {
@@ -65,24 +70,44 @@ public class DstoreConnection {
}
public String receive(String expectedMessage) throws DstoreDisconnectException {
+ String findMessage = checkQueue(expectedMessage);
+ if(findMessage != null) {
+ return findMessage;
+ }
+
System.out.println("Getting lock...");
synchronized(this) {
System.out.println("Lock acquired");
if(!available) return "ERROR";
- //Check the queue for the message before trying to receive any new messages (if no expected message is specified, return the head of the queue)
- for(int i=0; i<queue.size(); i++) {
- String message = queue.get(i);
- if(expectedMessage == null || expectedMessage.equals(message.split(" ")[0])) {
- queue.remove(message);
- return message;
- }
+ //Check the queue twice: once incase the receiver is busy, twice incase the message was added by the last thread
+ findMessage = checkQueue(expectedMessage);
+ if(findMessage != null) {
+ return findMessage;
}
return localReceive(expectedMessage);
}
}
+ //Check the queue for the message before trying to receive any new messages (if no expected message is specified, return the head of the queue)
+ protected String checkQueue(String expectedMessage) {
+ Iterator<String> it;
+ synchronized(queue) {
+ it = queue.iterator();
+ }
+
+ while(it.hasNext()) {
+ String message = it.next();
+ if(expectedMessage == null || expectedMessage.equals(message.split(" ")[0])) {
+ queue.remove(message);
+ return message;
+ }
+ }
+
+ return null;
+ }
+
public String receive() throws DstoreDisconnectException {
return receive(null);
}
diff --git a/DstoreDisconnectException.java b/DstoreDisconnectException.java
index 82cd0fd..8187f03 100644
--- a/DstoreDisconnectException.java
+++ b/DstoreDisconnectException.java
@@ -1,7 +1,21 @@
import java.lang.Throwable;
+import java.net.Socket;
public class DstoreDisconnectException extends Exception {
- public DstoreDisconnectException(int port) {
+ int port;
+ Socket socket;
+
+ public DstoreDisconnectException(int port, Socket socket) {
super("Dstore at port " + port + " has been disconnected");
+ this.port = port;
+ this.socket = socket;
+ }
+
+ public int getPort() {
+ return port;
+ }
+
+ public Socket getSocket() {
+ return socket;
}
}
diff --git a/to_store/Look Away.mp3 b/to_store/Look_Away.mp3
similarity index 100%
rename from to_store/Look Away.mp3
rename to to_store/Look_Away.mp3
--
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