content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.cassandra.auth;
  
  import java.util.HashSet;
  import java.util.Set;
  import java.util.StringJoiner;
  
  import com.google.common.base.Preconditions;
  import com.google.common.collect.ImmutableSet;
  import com.google.common.collect.Sets;
  
  import org.apache.cassandra.dht.Datacenters;
  import org.apache.cassandra.exceptions.InvalidRequestException;
  import org.apache.cassandra.tcm.ClusterMetadata;
  
  public abstract class DCPermissions
  {
      /**
       * returns true if the user can access the given dc
       */
      public abstract boolean canAccess(String dc);
  
      /**
       * Indicates whether the permissions object explicitly allow access to
       * some dcs (true) or if it implicitly allows access to all dcs (false)
       */
      public abstract boolean restrictsAccess();
      public abstract Set<String> allowedDCs();
      public abstract void validate();
  
      private static class SubsetPermissions extends DCPermissions
      {
          private final Set<String> subset;
  
          public SubsetPermissions(Set<String> subset)
          {
              Preconditions.checkNotNull(subset);
              this.subset = subset;
          }
  
          public boolean canAccess(String dc)
          {
              return subset.contains(dc);
          }
  
          public boolean restrictsAccess()
          {
              return true;
          }
  
          public Set<String> allowedDCs()
          {
              return ImmutableSet.copyOf(subset);
          }
  
          public boolean equals(Object o)
          {
              if (this == o) return true;
              if (o == null || getClass() != o.getClass()) return false;
  
              SubsetPermissions that = (SubsetPermissions) o;
  
              return subset.equals(that.subset);
          }
  
          public int hashCode()
          {
              return subset.hashCode();
          }
  
          public String toString()
          {
              StringJoiner joiner = new StringJoiner(", ");
              subset.forEach(joiner::add);
              return joiner.toString();
          }
  
          public void validate()
          {
              Set<String> unknownDcs = Sets.difference(subset, Datacenters.getValidDatacenters(ClusterMetadata.current()));
              if (!unknownDcs.isEmpty())
              {
                  throw new InvalidRequestException(String.format("Invalid value(s) for DATACENTERS '%s'," +
                                                                  "All values must be valid datacenters", subset));
              }
          }
      }
  
      private static final DCPermissions ALL = new DCPermissions()
      {
          public boolean canAccess(String dc)
          {
              return true;
          }
  
          public boolean restrictsAccess()
          {
              return false;
          }
  
          public Set<String> allowedDCs()
          {
              throw new UnsupportedOperationException();
          }
  
          public String toString()
          {
              return "ALL";
          }
  
          public void validate()
          {
  
          }
      };
  
      private static final DCPermissions NONE = new DCPermissions()
      {
          public boolean canAccess(String dc)
          {
              return false;
          }
  
          public boolean restrictsAccess()
          {
              return true;
          }
  
          public Set<String> allowedDCs()
          {
              throw new UnsupportedOperationException();
          }
  
          public String toString()
          {
              return "n/a";
          }
  
          public void validate()
          {
              throw new UnsupportedOperationException();
          }
      };
  
      public static DCPermissions all()
      {
          return ALL;
      }
  
      public static DCPermissions none()
      {
          return NONE;
      }
  
      public static DCPermissions subset(Set<String> dcs)
      {
          return new SubsetPermissions(dcs);
      }
  
      public static DCPermissions subset(String... dcs)
      {
          return subset(Sets.newHashSet(dcs));
      }
  
      public static class Builder
      {
          private Set<String> dcs = new HashSet<>();
          private boolean isAll = false;
          private boolean modified = false;
  
          public void add(String dc)
          {
              Preconditions.checkArgument(!isAll, "All has been set");
              dcs.add(dc);
              modified = true;
          }
  
          public void all()
          {
              Preconditions.checkArgument(dcs.isEmpty(), "DCs have already been set");
              isAll = true;
              modified = true;
          }
  
          public boolean isModified()
          {
              return modified;
          }
  
          public DCPermissions build()
          {
              if (dcs.isEmpty())
              {
                  return DCPermissions.all();
              }
              else
              {
                  return subset(dcs);
              }
          }
      }
  
      public static Builder builder()
      {
          return new Builder();
      }
  }
  