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.replication;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.CountDownLatch;
  import org.apache.bookkeeper.client.BKException;
  import org.apache.bookkeeper.meta.LedgerManager;
  import org.apache.bookkeeper.net.BookieId;
  import org.apache.bookkeeper.proto.BookkeeperInternalCallbacks.Processor;
  import org.apache.bookkeeper.replication.ReplicationException.BKAuditException;
  import org.apache.zookeeper.AsyncCallback;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Preparing bookie vs its corresponding ledgers. This will always look up the
   * ledgermanager for ledger metadata and will generate indexes.
   */
  public class BookieLedgerIndexer {
  
      private static final Logger LOG = LoggerFactory.getLogger(BookieLedgerIndexer.class);
      private final LedgerManager ledgerManager;
  
      public BookieLedgerIndexer(LedgerManager ledgerManager) {
          this.ledgerManager = ledgerManager;
      }
  
      /**
       * Generating bookie vs its ledgers map by reading all the ledgers in each
       * bookie and parsing its metadata.
       *
       * @return bookie2ledgersMap map of bookie vs ledgers
       * @throws BKAuditException
       *             exception while getting bookie-ledgers
       */
      public Map<String, Set<Long>> getBookieToLedgerIndex()
              throws BKAuditException {
          // bookie vs ledgers map
          final ConcurrentHashMap<String, Set<Long>> bookie2ledgersMap = new ConcurrentHashMap<String, Set<Long>>();
          final CountDownLatch ledgerCollectorLatch = new CountDownLatch(1);
  
          Processor<Long> ledgerProcessor = new Processor<Long>() {
                  @Override
                  public void process(Long ledgerId, AsyncCallback.VoidCallback iterCallback) {
                      ledgerManager.readLedgerMetadata(ledgerId).whenComplete((metadata, exception) -> {
                                  if (exception == null) {
                                      for (Map.Entry<Long, ? extends List<BookieId>> ensemble
                                               : metadata.getValue().getAllEnsembles().entrySet()) {
                                          for (BookieId bookie : ensemble.getValue()) {
                                              putLedger(bookie2ledgersMap, bookie.toString(), ledgerId);
                                          }
                                      }
                                      iterCallback.processResult(BKException.Code.OK, null, null);
                                  } else if (BKException.getExceptionCode(exception)
                                             == BKException.Code.NoSuchLedgerExistsOnMetadataServerException) {
                                      LOG.info("Ignoring replication of already deleted ledger {}", ledgerId);
                                      iterCallback.processResult(BKException.Code.OK, null, null);
                                  } else {
                                      LOG.warn("Unable to read the ledger: {} information", ledgerId);
                                      iterCallback.processResult(BKException.getExceptionCode(exception), null, null);
                                  }
                              });
                  }
              };
          // Reading the result after processing all the ledgers
          final List<Integer> resultCode = new ArrayList<Integer>(1);
          ledgerManager.asyncProcessLedgers(ledgerProcessor,
                  new AsyncCallback.VoidCallback() {
  
                      @Override
                      public void processResult(int rc, String s, Object obj) {
                          resultCode.add(rc);
                          ledgerCollectorLatch.countDown();
                      }
                  }, null, BKException.Code.OK, BKException.Code.ReadException);
          try {
              ledgerCollectorLatch.await();
          } catch (InterruptedException e) {
              Thread.currentThread().interrupt();
              throw new BKAuditException(
                      "Exception while getting the bookie-ledgers", e);
          }
          if (!resultCode.contains(BKException.Code.OK)) {
              throw new BKAuditException(
                      "Exception while getting the bookie-ledgers", BKException
                              .create(resultCode.get(0)));
          }
          return bookie2ledgersMap;
      }
  
      private void putLedger(ConcurrentHashMap<String, Set<Long>> bookie2ledgersMap,
              String bookie, long ledgerId) {
          Set<Long> ledgers = bookie2ledgersMap.get(bookie);
          // creates an empty list and add to bookie for keeping its ledgers
          if (ledgers == null) {
              ledgers = Collections.synchronizedSet(new HashSet<Long>());
              Set<Long> oldLedgers = bookie2ledgersMap.putIfAbsent(bookie, ledgers);
              if (oldLedgers != null) {
                  ledgers = oldLedgers;
              }
          }
          ledgers.add(ledgerId);
      }
  }
  