/**
    * 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.hadoop.hbase.regionserver;
  
  import java.io.IOException;
  import java.util.Collection;
  import java.util.List;
  import java.util.NavigableSet;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.io.HeapSize;
  import org.apache.hadoop.hbase.io.compress.Compression;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.HFileDataBlockEncoder;
  import org.apache.hadoop.hbase.protobuf.generated.WALProtos.CompactionDescriptor;
  import org.apache.hadoop.hbase.regionserver.compactions.CompactionContext;
  import org.apache.hadoop.hbase.regionserver.compactions.CompactionProgress;
  import org.apache.hadoop.hbase.regionserver.compactions.CompactionRequest;
  
  /**
   * Interface for objects that hold a column family in a Region. Its a memstore and a set of zero or
   * more StoreFiles, which stretch backwards over time.
   */
  @InterfaceAudience.Private
  @InterfaceStability.Evolving
  public interface Store extends HeapSize, StoreConfigInformation {
  
    /* The default priority for user-specified compaction requests.
     * The user gets top priority unless we have blocking compactions. (Pri <= 0)
     */ int PRIORITY_USER = 1;
    int NO_PRIORITY = Integer.MIN_VALUE;
  
    // General Accessors
    KeyValue.KVComparator getComparator();
  
    Collection<StoreFile> getStorefiles();
  
    /**
     * Close all the readers We don't need to worry about subsequent requests because the HRegion
     * holds a write lock that will prevent any more reads or writes.
     * @return the {@link StoreFile StoreFiles} that were previously being used.
     * @throws IOException on failure
     */
    Collection<StoreFile> close() throws IOException;
  
    /**
     * Return a scanner for both the memstore and the HStore files. Assumes we are not in a
     * compaction.
     * @param scan Scan to apply when scanning the stores
     * @param targetCols columns to scan
     * @return a scanner over the current key values
     * @throws IOException on failure
     */
    KeyValueScanner getScanner(Scan scan, final NavigableSet<byte[]> targetCols, long readPt)
        throws IOException;
  
    /**
     * Get all scanners with no filtering based on TTL (that happens further down
     * the line).
     * @param cacheBlocks
     * @param isGet
     * @param usePread
     * @param isCompaction
     * @param matcher
     * @param startRow
     * @param stopRow
     * @param readPt
     * @return all scanners for this store
     */
    List<KeyValueScanner> getScanners(
      boolean cacheBlocks,
      boolean isGet,
      boolean usePread,
      boolean isCompaction,
      ScanQueryMatcher matcher,
     byte[] startRow,
     byte[] stopRow,
     long readPt
   ) throws IOException;
 
   ScanInfo getScanInfo();
 
   /**
    * Adds or replaces the specified KeyValues.
    * <p>
    * For each KeyValue specified, if a cell with the same row, family, and qualifier exists in
    * MemStore, it will be replaced. Otherwise, it will just be inserted to MemStore.
    * <p>
    * This operation is atomic on each KeyValue (row/family/qualifier) but not necessarily atomic
    * across all of them.
    * @param cells
    * @param readpoint readpoint below which we can safely remove duplicate KVs
    * @return memstore size delta
    * @throws IOException
    */
   long upsert(Iterable<Cell> cells, long readpoint) throws IOException;
 
   /**
    * Adds a value to the memstore
    * @param kv
    * @return memstore size delta
    */
   long add(KeyValue kv);
 
   /**
    * When was the last edit done in the memstore
    */
   long timeOfOldestEdit();
 
   /**
    * Removes a kv from the memstore. The KeyValue is removed only if its key & memstoreTS match the
    * key & memstoreTS value of the kv parameter.
    * @param kv
    */
   void rollback(final KeyValue kv);
 
   /**
    * Find the key that matches <i>row</i> exactly, or the one that immediately precedes it. WARNING:
    * Only use this method on a table where writes occur with strictly increasing timestamps. This
    * method assumes this pattern of writes in order to make it reasonably performant. Also our
    * search is dependent on the axiom that deletes are for cells that are in the container that
    * follows whether a memstore snapshot or a storefile, not for the current container: i.e. we'll
    * see deletes before we come across cells we are to delete. Presumption is that the
    * memstore#kvset is processed before memstore#snapshot and so on.
    * @param row The row key of the targeted row.
    * @return Found keyvalue or null if none found.
    * @throws IOException
    */
   KeyValue getRowKeyAtOrBefore(final byte[] row) throws IOException;
 
   FileSystem getFileSystem();
 
   /*
    * @param maxKeyCount
    * @param compression Compression algorithm to use
    * @param isCompaction whether we are creating a new file in a compaction
    * @param includeMVCCReadpoint whether we should out the MVCC readpoint
    * @return Writer for a new StoreFile in the tmp dir.
    */
   StoreFile.Writer createWriterInTmp(
     long maxKeyCount,
     Compression.Algorithm compression,
     boolean isCompaction,
     boolean includeMVCCReadpoint,
     boolean includesTags
   ) throws IOException;
 
   // Compaction oriented methods
 
   boolean throttleCompaction(long compactionSize);
 
   /**
    * getter for CompactionProgress object
    * @return CompactionProgress object; can be null
    */
   CompactionProgress getCompactionProgress();
 
   CompactionContext requestCompaction() throws IOException;
 
   CompactionContext requestCompaction(int priority, CompactionRequest baseRequest)
       throws IOException;
 
   void cancelRequestedCompaction(CompactionContext compaction);
 
   List<StoreFile> compact(CompactionContext compaction) throws IOException;
 
   /**
    * @return true if we should run a major compaction.
    */
   boolean isMajorCompaction() throws IOException;
 
   void triggerMajorCompaction();
 
   /**
    * See if there's too much store files in this store
    * @return true if number of store files is greater than the number defined in minFilesToCompact
    */
   boolean needsCompaction();
 
   int getCompactPriority();
 
   StoreFlushContext createFlushContext(long cacheFlushId);
 
   /**
    * Call to complete a compaction. Its for the case where we find in the WAL a compaction
    * that was not finished.  We could find one recovering a WAL after a regionserver crash.
    * See HBASE-2331.
    * @param compaction
    */
   void completeCompactionMarker(CompactionDescriptor compaction)
       throws IOException;
 
   // Split oriented methods
 
   boolean canSplit();
 
   /**
    * Determines if Store should be split
    * @return byte[] if store should be split, null otherwise.
    */
   byte[] getSplitPoint();
 
   // Bulk Load methods
 
   /**
    * This throws a WrongRegionException if the HFile does not fit in this region, or an
    * InvalidHFileException if the HFile is not valid.
    */
   void assertBulkLoadHFileOk(Path srcPath) throws IOException;
 
   /**
    * This method should only be called from HRegion. It is assumed that the ranges of values in the
    * HFile fit within the stores assigned region. (assertBulkLoadHFileOk checks this)
    *
    * @param srcPathStr
    * @param sequenceId sequence Id associated with the HFile
    */
   void bulkLoadHFile(String srcPathStr, long sequenceId) throws IOException;
 
   // General accessors into the state of the store
   // TODO abstract some of this out into a metrics class
 
   /**
    * @return <tt>true</tt> if the store has any underlying reference files to older HFiles
    */
   boolean hasReferences();
 
   /**
    * @return The size of this store's memstore, in bytes
    */
   long getMemStoreSize();
 
   /**
    * @return The amount of memory we could flush from this memstore; usually this is equal to
    * {@link #getMemStoreSize()} unless we are carrying snapshots and then it will be the size of
    * outstanding snapshots.
    */
   long getFlushableSize();
 
   HColumnDescriptor getFamily();
 
   /**
    * @return The maximum memstoreTS in all store files.
    */
   long getMaxMemstoreTS();
 
   /**
    * @return the data block encoder
    */
   HFileDataBlockEncoder getDataBlockEncoder();
 
   /** @return aggregate size of all HStores used in the last compaction */
   long getLastCompactSize();
 
   /** @return aggregate size of HStore */
   long getSize();
 
   /**
    * @return Count of store files
    */
   int getStorefilesCount();
 
   /**
    * @return The size of the store files, in bytes, uncompressed.
    */
   long getStoreSizeUncompressed();
 
   /**
    * @return The size of the store files, in bytes.
    */
   long getStorefilesSize();
 
   /**
    * @return The size of the store file indexes, in bytes.
    */
   long getStorefilesIndexSize();
 
   /**
    * Returns the total size of all index blocks in the data block indexes, including the root level,
    * intermediate levels, and the leaf level for multi-level indexes, or just the root level for
    * single-level indexes.
    * @return the total size of block indexes in the store
    */
   long getTotalStaticIndexSize();
 
   /**
    * Returns the total byte size of all Bloom filter bit arrays. For compound Bloom filters even the
    * Bloom blocks currently not loaded into the block cache are counted.
    * @return the total size of all Bloom filters in the store
    */
   long getTotalStaticBloomSize();
 
   // Test-helper methods
 
   /**
    * Used for tests.
    * @return cache configuration for this Store.
    */
   CacheConfig getCacheConfig();
 
   /**
    * @return the parent region info hosting this store
    */
   HRegionInfo getRegionInfo();
 
   RegionCoprocessorHost getCoprocessorHost();
 
   boolean areWritesEnabled();
 
   /**
    * @return The smallest mvcc readPoint across all the scanners in this
    * region. Writes older than this readPoint, are included  in every
    * read operation.
    */
   long getSmallestReadPoint();
 
   String getColumnFamilyName();
 
   TableName getTableName();
 
   /**
    * @return The number of cells flushed to disk
    */
   long getFlushedCellsCount();
 
   /**
    * @return The total size of data flushed to disk, in bytes
    */
   long getFlushedCellsSize();
 
   /**
    * @return The number of cells processed during minor compactions
    */
   long getCompactedCellsCount();
 
   /**
    * @return The total amount of data processed during minor compactions, in bytes
    */
   long getCompactedCellsSize();
 
   /**
    * @return The number of cells processed during major compactions
    */
   long getMajorCompactedCellsCount();
 
   /**
    * @return The total amount of data processed during major compactions, in bytes
    */
   long getMajorCompactedCellsSize();
 
   /*
    * @param o Observer who wants to know about changes in set of Readers
    */
   void addChangedReaderObserver(ChangedReadersObserver o);
 
   /*
    * @param o Observer no longer interested in changes in set of Readers.
    */
   void deleteChangedReaderObserver(ChangedReadersObserver o);
 
   /**
    * @return Whether this store has too many store files.
    */
   boolean hasTooManyStoreFiles();
 }