/*
    * Copyright The Apache Software Foundation
    *
    * 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.filter;
  
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.KeyValueUtil;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
  
  import com.google.protobuf.InvalidProtocolBufferException;
  
  /**
   * This is a Filter wrapper class which is used in the server side. Some filter
   * related hooks can be defined in this wrapper. The only way to create a
   * FilterWrapper instance is passing a client side Filter instance through
   * {@link org.apache.hadoop.hbase.client.Scan#getFilter()}.
   * 
   */
  @InterfaceAudience.Private
  final public class FilterWrapper extends Filter {
    Filter filter = null;
  
    public FilterWrapper( Filter filter ) {
      if (null == filter) {
        // ensure the filter instance is not null
        throw new NullPointerException("Cannot create FilterWrapper with null Filter");
      }
      this.filter = filter;
    }
  
    /**
     * @return The filter serialized using pb
     */
    public byte[] toByteArray() throws IOException {
      FilterProtos.FilterWrapper.Builder builder =
        FilterProtos.FilterWrapper.newBuilder();
      builder.setFilter(ProtobufUtil.toFilter(this.filter));
      return builder.build().toByteArray();
    }
  
    /**
     * @param pbBytes A pb serialized {@link FilterWrapper} instance
     * @return An instance of {@link FilterWrapper} made from <code>bytes</code>
     * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
     * @see #toByteArray
     */
    public static FilterWrapper parseFrom(final byte [] pbBytes)
    throws DeserializationException {
      FilterProtos.FilterWrapper proto;
      try {
        proto = FilterProtos.FilterWrapper.parseFrom(pbBytes);
      } catch (InvalidProtocolBufferException e) {
        throw new DeserializationException(e);
      }
      try {
        return new FilterWrapper(ProtobufUtil.toFilter(proto.getFilter()));
      } catch (IOException ioe) {
        throw new DeserializationException(ioe);
      }
    }
  
    @Override
    public void reset() throws IOException {
      this.filter.reset();
    }
  
    @Override
    public boolean filterAllRemaining() throws IOException {
      return this.filter.filterAllRemaining();
    }
  
    @Override
    public boolean filterRow() throws IOException {
      return this.filter.filterRow();
    }
  
   /**
    * This method is deprecated and you should override Cell getNextKeyHint(Cell) instead.
    */
   @Override
   @Deprecated
   public KeyValue getNextKeyHint(KeyValue currentKV) throws IOException {
     // This will never get called.
     return KeyValueUtil.ensureKeyValue(this.filter.getNextCellHint((Cell)currentKV));
   }
 
   @Override
   public Cell getNextCellHint(Cell currentKV) throws IOException {
     return this.filter.getNextCellHint(currentKV);
   }
 
   @Override
   public boolean filterRowKey(byte[] buffer, int offset, int length) throws IOException {
     return this.filter.filterRowKey(buffer, offset, length);
   }
 
   @Override
   public ReturnCode filterKeyValue(Cell v) throws IOException {
     return this.filter.filterKeyValue(v);
   }
 
   @Override
   public Cell transformCell(Cell v) throws IOException {
     return this.filter.transformCell(v);
   }
 
   /**
    * WARNING: please to not override this method.  Instead override {@link #transformCell(Cell)}.
    *
    * This is for transition from 0.94 -&gt; 0.96
    */
   @Override
   @Deprecated
   public KeyValue transform(KeyValue currentKV) throws IOException {
     // This will never get called.
     return KeyValueUtil.ensureKeyValue(this.filter.transformCell(currentKV));
   }
 
   @Override
   public boolean hasFilterRow() {
     return this.filter.hasFilterRow();
   }
 
   @Override
   public void filterRowCells(List<Cell> kvs) throws IOException {
     filterRowCellsWithRet(kvs);
   }
 
   public enum FilterRowRetCode {
     NOT_CALLED,
     INCLUDE,     // corresponds to filter.filterRow() returning false
     EXCLUDE      // corresponds to filter.filterRow() returning true
   }
   public FilterRowRetCode filterRowCellsWithRet(List<Cell> kvs) throws IOException {
     //To fix HBASE-6429,
     //Filter with filterRow() returning true is incompatible with scan with limit
     //1. hasFilterRow() returns true, if either filterRow() or filterRow(kvs) is implemented.
     //2. filterRow() is merged with filterRow(kvs),
     //so that to make all those row related filtering stuff in the same function.
     this.filter.filterRowCells(kvs);
     if (!kvs.isEmpty()) {
       if (this.filter.filterRow()) {
         kvs.clear();
         return FilterRowRetCode.EXCLUDE;
       }
       return FilterRowRetCode.INCLUDE;
     }
     return FilterRowRetCode.NOT_CALLED;
   }
 
   @Override
   public boolean isFamilyEssential(byte[] name) throws IOException {
     return filter.isFamilyEssential(name);
   }
 
   /**
    * @param other
    * @return true if and only if the fields of the filter that are serialized
    * are equal to the corresponding fields in other.  Used for testing.
    */
   boolean areSerializedFieldsEqual(Filter o) {
     if (o == this) return true;
     if (!(o instanceof FilterWrapper)) return false;
 
     FilterWrapper other = (FilterWrapper)o;
     return this.filter.areSerializedFieldsEqual(other.filter);
   }
 }