simple db makeover

server/SimpleDB.java

@@ -4,10 +4,12 @@
 
 import java.io.PrintWriter;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Random;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import rpc.RpcServer;
 import rpc.message.RpcMessageCall;
@@ -38,16 +40,16 @@ public final class SimpleDB extends Thread {
  private static AmazonSimpleDBClient sdbc = null;
  private static String AttrName = "IPP";
 
- private static final HashSet<IPP> localMbrList = new HashSet<IPP>();
-  
+ //private static final HashSet<IPP> localMbrList = new HashSet<IPP>();
+ Set<IPP> localMbrList = Collections.newSetFromMap(new ConcurrentHashMap<IPP, Boolean>());
  private static SimpleDB db = new SimpleDB();
 
  private SimpleDB() {
  oAWSCredentials = new BasicAWSCredentials(getKey(), getSecret());
  sdbc = new AmazonSimpleDBClient(oAWSCredentials);
  }
 
- public synchronized void createDomain(String domain){
+ public void createDomain(String domain){
  if(DEBUG) System.out.println("Connecting and creating domain (" + domain + ")");
  sdbc.createDomain(new CreateDomainRequest(domain));
 
@@ -73,14 +75,14 @@ public synchronized void createDomain(String domain){
  }
  }
 
- public synchronized void deleteDomain(String domain){
+ public void deleteDomain(String domain){
  if(DEBUG) System.out.println("Deleting domain ("+domain +")");
  DeleteDomainRequest deleteDomainRequest = new DeleteDomainRequest();
  deleteDomainRequest.setDomainName(domain);
  sdbc.deleteDomain(deleteDomainRequest);
  }
 
- public synchronized void memberRefresh(){
+ public void memberRefresh(){
  //Set the local MbrSet to empty.
  localMbrList.clear();
 
@@ -135,11 +137,11 @@ public synchronized void memberRefresh(){
  }
  }
 
- public synchronized void deleteLocalMember(IPP ipp){
+ public void deleteLocalMember(IPP ipp){
  localMbrList.remove(ipp);
  }
 
- public synchronized void putLocalMember(IPP ipp){
+ public void putLocalMember(IPP ipp){
  localMbrList.add(ipp);
  }
 
@@ -152,7 +154,7 @@ private String trimAndToString(ArrayList<IPP> list){
  return " ";
  return list.toString().replace("[", "").replace("]", "");
  }
- public synchronized ArrayList<IPP> getLocalMembers(){
+ public ArrayList<IPP> getLocalMembers(){
  ArrayList<IPP> result = new ArrayList<IPP>();
  result.addAll(localMbrList);
  return result;
@@ -189,7 +191,7 @@ private ArrayList<IPP> getMembers(){
  return servers;
  }
 
- public synchronized void listDomains(PrintWriter out) {
+ public void listDomains(PrintWriter out) {
  for(String domainName : sdbc.listDomains().getDomainNames()){
  out.println("Domain: " + domainName);
  }
@@ -225,7 +227,7 @@ public void run() {
  double probOfRefresh = 1.0/localMbrList.size();
  double rand = generator.nextDouble();
 
- //if(rand <= probOfRefresh)
+ if(rand <= probOfRefresh)
  memberRefresh();
  } catch (InterruptedException e) {
  e.printStackTrace();