/**
    * 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.replication;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.wal.WAL.Entry;
  
  /**
   * A {@link WALEntryFilter} which contains multiple filters and applies them
   * in chain order
   */
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.REPLICATION)
  public class ChainWALEntryFilter implements WALEntryFilter {
  
    private final WALEntryFilter[] filters;
    private WALCellFilter[] cellFilters;
  
    public ChainWALEntryFilter(WALEntryFilter...filters) {
      this.filters = filters;
      initCellFilters();
    }
  
    public ChainWALEntryFilter(List<WALEntryFilter> filters) {
      ArrayList<WALEntryFilter> rawFilters = new ArrayList<WALEntryFilter>(filters.size());
      // flatten the chains
      for (WALEntryFilter filter : filters) {
        if (filter instanceof ChainWALEntryFilter) {
          Collections.addAll(rawFilters, ((ChainWALEntryFilter) filter).filters);
        } else {
          rawFilters.add(filter);
        }
      }
      this.filters = rawFilters.toArray(new WALEntryFilter[rawFilters.size()]);
      initCellFilters();
    }
  
    public void initCellFilters() {
      ArrayList<WALCellFilter> cellFilters = new ArrayList<>(filters.length);
      for (WALEntryFilter filter : filters) {
        if (filter instanceof WALCellFilter) {
          cellFilters.add((WALCellFilter) filter);
        }
      }
      this.cellFilters = cellFilters.toArray(new WALCellFilter[cellFilters.size()]);
    }
  
    @Override
    public Entry filter(Entry entry) {
      for (WALEntryFilter filter : filters) {
        if (entry == null) {
          return null;
        }
        entry = filter.filter(entry);
      }
      filterCells(entry);
      return entry;
    }
  
    private void filterCells(Entry entry) {
      if (entry == null || cellFilters.length == 0) {
        return;
      }
      ArrayList<Cell> cells = entry.getEdit().getCells();
      int size = cells.size();
      for (int i = size - 1; i >= 0; i--) {
        Cell cell = cells.get(i);
        for (WALCellFilter filter : cellFilters) {
          cell = filter.filterCell(entry, cell);
          if (cell != null) {
            cells.set(i, cell);
          } else {
            cells.remove(i);
            break;
          }
        }
      }
      if (cells.size() < size / 2) {
       cells.trimToSize();
     }
   }
 }