server/manager/src/main/java/org/apache/accumulo/manager/tableOps/namespace/rename/RenameNamespace.java

/*
 * 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
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package org.apache.accumulo.manager.tableOps.namespace.rename;

import static java.nio.charset.StandardCharsets.UTF_8;

import org.apache.accumulo.core.Constants;
import org.apache.accumulo.core.clientImpl.AcceptableThriftTableOperationException;
import org.apache.accumulo.core.clientImpl.Tables;
import org.apache.accumulo.core.clientImpl.thrift.TableOperation;
import org.apache.accumulo.core.clientImpl.thrift.TableOperationExceptionType;
import org.apache.accumulo.core.data.NamespaceId;
import org.apache.accumulo.fate.Repo;
import org.apache.accumulo.fate.zookeeper.ZooReaderWriter;
import org.apache.accumulo.manager.Manager;
import org.apache.accumulo.manager.tableOps.ManagerRepo;
import org.apache.accumulo.manager.tableOps.Utils;
import org.slf4j.LoggerFactory;

public class RenameNamespace extends ManagerRepo {

  private static final long serialVersionUID = 1L;
  private NamespaceId namespaceId;
  private String oldName;
  private String newName;

  @Override
  public long isReady(long id, Manager environment) throws Exception {
    return Utils.reserveNamespace(environment, namespaceId, id, true, true, TableOperation.RENAME);
  }

  public RenameNamespace(NamespaceId namespaceId, String oldName, String newName) {
    this.namespaceId = namespaceId;
    this.oldName = oldName;
    this.newName = newName;
  }

  @Override
  public Repo<Manager> call(long id, Manager manager) throws Exception {

    ZooReaderWriter zoo = manager.getContext().getZooReaderWriter();

    Utils.getTableNameLock().lock();
    try {
      Utils.checkNamespaceDoesNotExist(manager.getContext(), newName, namespaceId,
          TableOperation.RENAME);

      final String tap = manager.getZooKeeperRoot() + Constants.ZNAMESPACES + "/" + namespaceId
          + Constants.ZNAMESPACE_NAME;

      zoo.mutateExisting(tap, current -> {
        final String currentName = new String(current, UTF_8);
        if (currentName.equals(newName))
          return null; // assume in this case the operation is running again, so we are done
        if (!currentName.equals(oldName)) {
          throw new AcceptableThriftTableOperationException(null, oldName, TableOperation.RENAME,
              TableOperationExceptionType.NAMESPACE_NOTFOUND, "Name changed while processing");
        }
        return newName.getBytes(UTF_8);
      });
      Tables.clearCache(manager.getContext());
    } finally {
      Utils.getTableNameLock().unlock();
      Utils.unreserveNamespace(manager, namespaceId, id, true);
    }

    LoggerFactory.getLogger(RenameNamespace.class).debug("Renamed namespace {} {} {}", namespaceId,
        oldName, newName);

    return null;
  }

  @Override
  public void undo(long tid, Manager env) {
    Utils.unreserveNamespace(env, namespaceId, tid, true);
  }

}