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.bookkeeper.meta;
  
  import static org.apache.bookkeeper.util.BookKeeperConstants.LAYOUT_ZNODE;
  
  import com.google.common.annotations.VisibleForTesting;
  import java.io.IOException;
  import java.util.List;
  import org.apache.zookeeper.CreateMode;
  import org.apache.zookeeper.KeeperException;
  import org.apache.zookeeper.KeeperException.NoNodeException;
  import org.apache.zookeeper.KeeperException.NodeExistsException;
  import org.apache.zookeeper.ZooKeeper;
  import org.apache.zookeeper.data.ACL;
  
  /**
   * Provide utils for writing/reading/deleting layout in zookeeper.
   */
  public class ZkLayoutManager implements LayoutManager {
  
      private final ZooKeeper zk;
      private final String ledgersLayout;
      private final List<ACL> acls;
  
      public ZkLayoutManager(ZooKeeper zk,
                             String ledgersRoot,
                             List<ACL> acls) {
          this.zk = zk;
          this.ledgersLayout = ledgersRoot + "/" + LAYOUT_ZNODE;
          this.acls = acls;
      }
  
      @VisibleForTesting
      public ZooKeeper getZk() {
          return zk;
      }
  
      /**
       * Read ledger layout from zookeeper.
       *
       * @return ledger layout, or null if none set in zookeeper
       */
      @Override
      public LedgerLayout readLedgerLayout() throws IOException {
          try {
              byte[] layoutData = zk.getData(ledgersLayout, false, null);
              return LedgerLayout.parseLayout(layoutData);
          } catch (NoNodeException nne) {
              return null;
          } catch (InterruptedException e) {
              Thread.currentThread().interrupt();
              throw new IOException(e);
          } catch (KeeperException e) {
              throw new IOException(e);
          }
      }
  
      /**
       * Store the ledger layout to zookeeper.
       */
      @Override
      public void storeLedgerLayout(LedgerLayout layout) throws IOException {
          try {
              zk.create(ledgersLayout, layout.serialize(), acls,
                  CreateMode.PERSISTENT);
          } catch (NodeExistsException e) {
              throw new LedgerLayoutExistsException(e);
          } catch (KeeperException e) {
              throw new IOException(e);
          } catch (InterruptedException e) {
              Thread.currentThread().interrupt();
              throw new IOException(e);
          }
      }
  
      /**
       * Delete the ledger layout from zookeeper.
       */
      @Override
      public void deleteLedgerLayout() throws IOException {
          try {
              zk.delete(ledgersLayout, -1);
          } catch (InterruptedException e) {
              Thread.currentThread().interrupt();
              throw new IOException(e);
          } catch (KeeperException e) {
              throw new IOException(e);
          }
      }
  }
  