code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.sdk.server.identity;
  
  import java.util.Iterator;
  import java.util.List;
  
  import com.google.common.collect.ImmutableList;
  import org.eclipse.milo.opcua.sdk.server.Session;
  import org.eclipse.milo.opcua.stack.core.StatusCodes;
  import org.eclipse.milo.opcua.stack.core.UaException;
  import org.eclipse.milo.opcua.stack.core.types.structured.SignatureData;
  import org.eclipse.milo.opcua.stack.core.types.structured.UserIdentityToken;
  import org.eclipse.milo.opcua.stack.core.types.structured.UserTokenPolicy;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A composite {@link IdentityValidator} that tries its component {@link IdentityValidator}s in the order provided.
   */
  public class CompositeValidator<T> implements IdentityValidator<T> {
  
      private final Logger logger = LoggerFactory.getLogger(getClass());
  
      private final ImmutableList<IdentityValidator<T>> validators;
  
      public CompositeValidator(IdentityValidator<T>... validators) {
          this.validators = ImmutableList.copyOf(validators);
      }
  
      public CompositeValidator(List<IdentityValidator<T>> validators) {
          this.validators = ImmutableList.copyOf(validators);
      }
  
      @Override
      public T validateIdentityToken(
          Session session,
          UserIdentityToken token,
          UserTokenPolicy tokenPolicy,
          SignatureData tokenSignature) throws UaException {
  
          Iterator<IdentityValidator<T>> iterator = validators.iterator();
  
          while (iterator.hasNext()) {
              IdentityValidator<T> validator = iterator.next();
  
              try {
                  return validator.validateIdentityToken(session, token, tokenPolicy, tokenSignature);
              } catch (Exception e) {
                  if (!iterator.hasNext()) {
                      throw e;
                  }
  
                  logger.debug("IdentityValidator={} failed, trying next...", validator.toString());
              }
          }
  
          throw new UaException(StatusCodes.Bad_IdentityTokenInvalid);
      }
  
  }
  