content: /**
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.aurora.scheduler.http.api.security;
  
  import javax.inject.Provider;
  
  import com.google.inject.Inject;
  
  import org.aopalliance.intercept.MethodInterceptor;
  import org.aopalliance.intercept.MethodInvocation;
  import org.apache.shiro.authz.UnauthenticatedException;
  import org.apache.shiro.subject.Subject;
  
  import static java.util.Objects.requireNonNull;
  
  import static com.google.common.base.Preconditions.checkState;
  
  /**
   * Prevents invocation of intercepted methods if the current {@link Subject} is not authenticated.
   */
  class ShiroAuthenticatingThriftInterceptor implements MethodInterceptor {
    private volatile boolean initialized;
  
    private Provider<Subject> subjectProvider;
  
    ShiroAuthenticatingThriftInterceptor() {
      // Guice constructor.
    }
  
    @Inject
    void initialize(Provider<Subject> newSubjectProvider) {
      checkState(!initialized);
  
      subjectProvider = requireNonNull(newSubjectProvider);
  
      initialized = true;
    }
  
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
      checkState(initialized);
      Subject subject = subjectProvider.get();
      if (subject.isAuthenticated()) {
        return invocation.proceed();
      } else {
        // This is a special exception that will signal the BasicHttpAuthenticationFilter to send
        // a 401 with a challenge. This is necessary at this layer since we only apply this
        // interceptor to methods that require authentication.
        throw new UnauthenticatedException();
      }
    }
  }
  