public ComputeServiceContext getContext(Provider provider) {
   ComputeServiceContext context = contextForProvider.get(provider);
   Credentials credentials = provider.getCredentials();
   if (context == null && provider.areCredentialsSetup()) {
     provider.registerCredentialsChangedListener(this);
     context =
         ContextBuilder.newBuilder(provider.getId())
             .credentials(credentials.getKey(), credentials.getSecret())
             .modules(ImmutableSet.<Module>of(new JschSshClientModule()))
             .buildView(ComputeServiceContext.class);
   }
   return context;
 }
 public Provider getProviderById(String id) {
   for (Provider provider : providers) {
     if (provider.getId().equals(id)) return provider;
   }
   return null;
 }