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.bookie;
  
  import io.netty.buffer.ByteBuf;
  import java.io.IOException;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  import java.util.PrimitiveIterator.OfLong;
  import org.apache.bookkeeper.common.util.Watcher;
  import org.apache.bookkeeper.conf.ServerConfiguration;
  import org.apache.bookkeeper.stats.NullStatsLogger;
  import org.apache.bookkeeper.stats.StatsLogger;
  import org.apache.bookkeeper.util.SnapshotMap;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Implementation of LedgerCache interface.
   * This class serves two purposes.
   */
  public class LedgerCacheImpl implements LedgerCache {
      private static final Logger LOG = LoggerFactory.getLogger(LedgerCacheImpl.class);
  
      private final IndexInMemPageMgr indexPageManager;
      private final IndexPersistenceMgr indexPersistenceManager;
      private final int pageSize;
      private final int entriesPerPage;
  
      public LedgerCacheImpl(ServerConfiguration conf, SnapshotMap<Long, Boolean> activeLedgers,
                             LedgerDirsManager ledgerDirsManager) throws IOException {
          this(conf, activeLedgers, ledgerDirsManager, NullStatsLogger.INSTANCE);
      }
  
      public LedgerCacheImpl(ServerConfiguration conf, SnapshotMap<Long, Boolean> activeLedgers,
                             LedgerDirsManager ledgerDirsManager, StatsLogger statsLogger) throws IOException {
          this.pageSize = conf.getPageSize();
          this.entriesPerPage = pageSize / 8;
          this.indexPersistenceManager = new IndexPersistenceMgr(pageSize, entriesPerPage, conf, activeLedgers,
                  ledgerDirsManager, statsLogger);
          this.indexPageManager = new IndexInMemPageMgr(pageSize, entriesPerPage, conf,
                  indexPersistenceManager, statsLogger);
      }
  
      IndexPersistenceMgr getIndexPersistenceManager() {
          return indexPersistenceManager;
      }
  
      IndexInMemPageMgr getIndexPageManager() {
          return indexPageManager;
      }
  
      /**
       * @return page size used in ledger cache
       */
      public int getPageSize() {
          return pageSize;
      }
  
      @Override
      public Long getLastAddConfirmed(long ledgerId) throws IOException {
          return indexPersistenceManager.getLastAddConfirmed(ledgerId);
      }
  
      @Override
      public long updateLastAddConfirmed(long ledgerId, long lac) throws IOException {
          return indexPersistenceManager.updateLastAddConfirmed(ledgerId, lac);
      }
  
      @Override
      public boolean waitForLastAddConfirmedUpdate(long ledgerId,
                                                   long previousLAC,
                                                   Watcher<LastAddConfirmedUpdateNotification> watcher)
              throws IOException {
          return indexPersistenceManager.waitForLastAddConfirmedUpdate(ledgerId, previousLAC, watcher);
      }
  
      @Override
      public void cancelWaitForLastAddConfirmedUpdate(long ledgerId,
                                                      Watcher<LastAddConfirmedUpdateNotification> watcher)
              throws IOException {
          indexPersistenceManager.cancelWaitForLastAddConfirmedUpdate(ledgerId, watcher);
      }
  
      @Override
      public void putEntryOffset(long ledger, long entry, long offset) throws IOException {
          indexPageManager.putEntryOffset(ledger, entry, offset);
      }
  
      @Override
      public long getEntryOffset(long ledger, long entry) throws IOException {
          return indexPageManager.getEntryOffset(ledger, entry);
      }
  
      @Override
      public void flushLedger(boolean doAll) throws IOException {
          indexPageManager.flushOneOrMoreLedgers(doAll);
      }
  
      @Override
      public long getLastEntry(long ledgerId) throws IOException {
          // Get the highest entry from the pages that are in memory
          long lastEntryInMem = indexPageManager.getLastEntryInMem(ledgerId);
          // Some index pages may have been evicted from memory, retrieve the last entry
          // from the persistent store. We will check if there could be an entry beyond the
          // last in mem entry and only then attempt to get the last persisted entry from the file
          // The latter is just an optimization
          long lastEntry = indexPersistenceManager.getPersistEntryBeyondInMem(ledgerId, lastEntryInMem);
          return lastEntry;
      }
  
      /**
       * This method is called whenever a ledger is deleted by the BookKeeper Client
       * and we want to remove all relevant data for it stored in the LedgerCache.
       */
      @Override
      public void deleteLedger(long ledgerId) throws IOException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("Deleting ledgerId: {}", ledgerId);
          }
  
          indexPageManager.removePagesForLedger(ledgerId);
          indexPersistenceManager.removeLedger(ledgerId);
      }
  
      @Override
      public byte[] readMasterKey(long ledgerId) throws IOException, BookieException {
          return indexPersistenceManager.readMasterKey(ledgerId);
      }
  
      @Override
      public boolean setFenced(long ledgerId) throws IOException {
          return indexPersistenceManager.setFenced(ledgerId);
      }
  
      @Override
      public boolean isFenced(long ledgerId) throws IOException {
          return indexPersistenceManager.isFenced(ledgerId);
      }
  
      @Override
      public void setExplicitLac(long ledgerId, ByteBuf lac) throws IOException {
          indexPersistenceManager.setExplicitLac(ledgerId, lac);
      }
  
      @Override
      public ByteBuf getExplicitLac(long ledgerId) {
          return indexPersistenceManager.getExplicitLac(ledgerId);
      }
  
      @Override
      public void setMasterKey(long ledgerId, byte[] masterKey) throws IOException {
          indexPersistenceManager.setMasterKey(ledgerId, masterKey);
      }
  
      @Override
      public boolean ledgerExists(long ledgerId) throws IOException {
          return indexPersistenceManager.ledgerExists(ledgerId);
      }
  
      @Override
      public void close() throws IOException {
          indexPersistenceManager.close();
      }
  
      @Override
      public PageEntriesIterable listEntries(long ledgerId) throws IOException {
          return indexPageManager.listEntries(ledgerId);
      }
  
      @Override
      public LedgerIndexMetadata readLedgerIndexMetadata(long ledgerId) throws IOException {
          return indexPersistenceManager.readLedgerIndexMetadata(ledgerId);
      }
  
      @Override
      public OfLong getEntriesIterator(long ledgerId) throws IOException {
          Iterator<LedgerCache.PageEntries> pageEntriesIteratorNonFinal = null;
          try {
              pageEntriesIteratorNonFinal = listEntries(ledgerId).iterator();
          } catch (Bookie.NoLedgerException noLedgerException) {
              pageEntriesIteratorNonFinal = Collections.emptyIterator();
          }
          final Iterator<LedgerCache.PageEntries> pageEntriesIterator = pageEntriesIteratorNonFinal;
          return new OfLong() {
              private OfLong entriesInCurrentLEPIterator = null;
              {
                  if (pageEntriesIterator.hasNext()) {
                      entriesInCurrentLEPIterator = pageEntriesIterator.next().getLEP().getEntriesIterator();
                  }
              }
  
              @Override
              public boolean hasNext() {
                  try {
                      while ((entriesInCurrentLEPIterator != null) && (!entriesInCurrentLEPIterator.hasNext())) {
                          if (pageEntriesIterator.hasNext()) {
                              entriesInCurrentLEPIterator = pageEntriesIterator.next().getLEP().getEntriesIterator();
                          } else {
                              entriesInCurrentLEPIterator = null;
                          }
                      }
                      return (entriesInCurrentLEPIterator != null);
                  } catch (Exception exc) {
                      throw new RuntimeException(
                              "Received exception in InterleavedLedgerStorage getEntriesOfLedger hasNext call", exc);
                  }
              }
  
              @Override
              public long nextLong() {
                  if (!hasNext()) {
                      throw new NoSuchElementException();
                  }
                  return entriesInCurrentLEPIterator.nextLong();
              }
          };
      }
  }
  