content: package org.apache.bookkeeper.meta;
  
  /*
   * 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.
   */
  
  import java.io.IOException;
  import java.util.NoSuchElementException;
  import java.util.Set;
  import org.apache.bookkeeper.conf.AbstractConfiguration;
  import org.apache.bookkeeper.proto.BookkeeperInternalCallbacks.Processor;
  import org.apache.bookkeeper.util.StringUtils;
  import org.apache.bookkeeper.util.ZkUtils;
  import org.apache.zookeeper.AsyncCallback;
  import org.apache.zookeeper.KeeperException;
  import org.apache.zookeeper.ZooKeeper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Manage all ledgers in a single zk node.
   *
   * <p>
   * All ledgers' metadata are put in a single zk node, created using zk sequential node.
   * Each ledger node is prefixed with 'L'.
   * </p>
   */
  class FlatLedgerManager extends AbstractZkLedgerManager {
  
      static final Logger LOG = LoggerFactory.getLogger(FlatLedgerManager.class);
      // path prefix to store ledger znodes
      private final String ledgerPrefix;
  
      /**
       * Constructor.
       *
       * @param conf
       *          Configuration object
       * @param zk
       *          ZooKeeper Client Handle
       * @throws IOException when version is not compatible
       */
      public FlatLedgerManager(AbstractConfiguration conf, ZooKeeper zk) {
          super(conf, zk);
  
          ledgerPrefix = ledgerRootPath + "/" + StringUtils.LEDGER_NODE_PREFIX;
      }
  
      @Override
      public String getLedgerPath(long ledgerId) {
          StringBuilder sb = new StringBuilder();
          sb.append(ledgerPrefix)
            .append(StringUtils.getZKStringId(ledgerId));
          return sb.toString();
      }
  
      @Override
      public long getLedgerId(String nodeName) throws IOException {
          long ledgerId;
          try {
              String[] parts = nodeName.split(ledgerPrefix);
              ledgerId = Long.parseLong(parts[parts.length - 1]);
          } catch (NumberFormatException e) {
              throw new IOException(e);
          }
          return ledgerId;
      }
  
      @Override
      public void asyncProcessLedgers(final Processor<Long> processor,
                                      final AsyncCallback.VoidCallback finalCb, final Object ctx,
                                      final int successRc, final int failureRc) {
          asyncProcessLedgersInSingleNode(ledgerRootPath, processor, finalCb, ctx, successRc, failureRc);
      }
  
      @Override
      public LedgerRangeIterator getLedgerRanges(long zkOpTimeoutMs) {
          return new LedgerRangeIterator() {
              // single iterator, can visit only one time
              boolean nextCalled = false;
              LedgerRange nextRange = null;
  
              private synchronized void preload() throws IOException {
                  if (nextRange != null) {
                      return;
                  }
                  Set<Long> zkActiveLedgers = null;
  
                  try {
                      zkActiveLedgers = ledgerListToSet(
                              ZkUtils.getChildrenInSingleNode(zk, ledgerRootPath, zkOpTimeoutMs),
                              ledgerRootPath);
                      nextRange = new LedgerRange(zkActiveLedgers);
                  } catch (KeeperException.NoNodeException e) {
                      throw new IOException("Path does not exist: " + ledgerRootPath, e);
                  } catch (InterruptedException ie) {
                      Thread.currentThread().interrupt();
                      throw new IOException("Error when get child nodes from zk", ie);
                  }
              }
  
              @Override
              public synchronized boolean hasNext() throws IOException {
                  preload();
                  return nextRange != null && nextRange.size() > 0 && !nextCalled;
              }
  
              @Override
              public synchronized LedgerRange next() throws IOException {
                  if (!hasNext()) {
                      throw new NoSuchElementException();
                  }
                  nextCalled = true;
                  return nextRange;
              }
          };
      }
  
      @Override
      protected String getLedgerParentNodeRegex() {
          return StringUtils.FLAT_LEDGER_NODE_REGEX;
      }
  }
  