Lookup Table

lookup_table.java

       private static InetAddress[] checkLookupTable(String host) {
           synchronized (lookupTable) {
               // If the host isn't in the lookupTable, add it in the
               // lookuptable and return null. The caller should do
               // the lookup.
               if (lookupTable.containsKey(host) == false) {
                   lookupTable.put(host, null);
                   return null;
               }
   
               // If the host is in the lookupTable, it means that another
               // thread is trying to look up the addresses of this host.
               // This thread should wait.
               while (lookupTable.containsKey(host)) {
                   try {
                       lookupTable.wait();
                   } catch (InterruptedException e) {
                   }
               }
           }