/*
    *
    * 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 org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.Cell;
  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;
  
  /**
   * A wrapper filter that filters an entire row if any of the Cell checks do
   * not pass.
   * <p>
   * For example, if all columns in a row represent weights of different things,
   * with the values being the actual weights, and we want to filter out the
   * entire row if any of its weights are zero.  In this case, we want to prevent
   * rows from being emitted if a single key is filtered.  Combine this filter
   * with a {@link ValueFilter}:
   * </p>
   * <p>
   * <code>
   * scan.setFilter(new SkipFilter(new ValueFilter(CompareOp.NOT_EQUAL,
   *     new BinaryComparator(Bytes.toBytes(0))));
   * </code>
   * Any row which contained a column whose value was 0 will be filtered out
   * (since ValueFilter will not pass that Cell).
   * Without this filter, the other non-zero valued columns in the row would still
   * be emitted.
   * </p>
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class SkipFilter extends FilterBase {
    private boolean filterRow = false;
    private Filter filter;
  
    public SkipFilter(Filter filter) {
      this.filter = filter;
    }
  
    public Filter getFilter() {
      return filter;
    }
  
    @Override
    public void reset() throws IOException {
      filter.reset();
      filterRow = false;
    }
  
    private void changeFR(boolean value) {
      filterRow = filterRow || value;
    }
  
    @Override
    public ReturnCode filterKeyValue(Cell v) throws IOException {
      ReturnCode c = filter.filterKeyValue(v);
      changeFR(c != ReturnCode.INCLUDE);
      return c;
    }
  
    @Override
    public Cell transformCell(Cell v) throws IOException {
      return filter.transformCell(v);
    }
  
    @Override
    public boolean filterRow() {
      return filterRow;
    }
      
    @Override
    public boolean hasFilterRow() {
      return true;
    }
  
   /**
    * @return The filter serialized using pb
    */
   @Override
   public byte[] toByteArray() throws IOException {
     FilterProtos.SkipFilter.Builder builder =
       FilterProtos.SkipFilter.newBuilder();
     builder.setFilter(ProtobufUtil.toFilter(this.filter));
     return builder.build().toByteArray();
   }
 
   /**
    * @param pbBytes A pb serialized {@link SkipFilter} instance
    * @return An instance of {@link SkipFilter} made from <code>bytes</code>
    * @throws DeserializationException
    * @see #toByteArray
    */
   public static SkipFilter parseFrom(final byte [] pbBytes)
   throws DeserializationException {
     FilterProtos.SkipFilter proto;
     try {
       proto = FilterProtos.SkipFilter.parseFrom(pbBytes);
     } catch (InvalidProtocolBufferException e) {
       throw new DeserializationException(e);
     }
     try {
       return new SkipFilter(ProtobufUtil.toFilter(proto.getFilter()));
     } catch (IOException ioe) {
       throw new DeserializationException(ioe);
     }
   }
 
   /**
    * @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.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
     if (o == this) return true;
     if (!(o instanceof SkipFilter)) return false;
 
     SkipFilter other = (SkipFilter)o;
     return getFilter().areSerializedFieldsEqual(other.getFilter());
   }
 
   @Override
   public boolean isFamilyEssential(byte[] name) throws IOException {
     return filter.isFamilyEssential(name);
   }
 
   @Override
   public String toString() {
     return this.getClass().getSimpleName() + " " + this.filter.toString();
   }
 }