/**
    *
    * 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 com.google.common.base.Preconditions;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.CompareType;
  import org.apache.hadoop.hbase.util.Bytes;
  
  import java.util.ArrayList;
  import java.util.Objects;
  
  /**
   * This is a generic filter to be used to filter by comparison.  It takes an
   * operator (equal, greater, not equal, etc) and a byte [] comparator.
   * <p>
   * To filter by row key, use {@link RowFilter}.
   * <p>
   * To filter by column qualifier, use {@link QualifierFilter}.
   * <p>
   * To filter by value, use {@link SingleColumnValueFilter}.
   * <p>
   * These filters can be wrapped with {@link SkipFilter} and {@link WhileMatchFilter}
   * to add more control.
   * <p>
   * Multiple filters can be combined using {@link FilterList}.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public abstract class CompareFilter extends FilterBase {
  
    /** Comparison operators. */
    @InterfaceAudience.Public
    @InterfaceStability.Stable
    public enum CompareOp {
      /** less than */
      LESS,
      /** less than or equal to */
      LESS_OR_EQUAL,
      /** equals */
      EQUAL,
      /** not equal */
      NOT_EQUAL,
      /** greater than or equal to */
      GREATER_OR_EQUAL,
      /** greater than */
      GREATER,
      /** no operation */
      NO_OP,
    }
  
    protected CompareOp compareOp;
    protected ByteArrayComparable comparator;
  
    /**
     * Constructor.
     * @param compareOp the compare op for row matching
     * @param comparator the comparator for row matching
     */
    public CompareFilter(final CompareOp compareOp,
        final ByteArrayComparable comparator) {
      this.compareOp = compareOp;
      this.comparator = comparator;
    }
  
    /**
     * @return operator
     */
    public CompareOp getOperator() {
      return compareOp;
    }
  
    /**
     * @return the comparator
     */
    public ByteArrayComparable getComparator() {
     return comparator;
   }
 
   protected boolean doCompare(final CompareOp compareOp,
       final ByteArrayComparable comparator, final byte [] data,
       final int offset, final int length) {
     if (compareOp == CompareOp.NO_OP) {
       return true;
     }
     int compareResult = comparator.compareTo(data, offset, length);
     switch (compareOp) {
       case LESS:
         return compareResult <= 0;
       case LESS_OR_EQUAL:
         return compareResult < 0;
       case EQUAL:
         return compareResult != 0;
       case NOT_EQUAL:
         return compareResult == 0;
       case GREATER_OR_EQUAL:
         return compareResult > 0;
       case GREATER:
         return compareResult >= 0;
       default:
         throw new RuntimeException("Unknown Compare op " +
           compareOp.name());
     }
   }
 
   // Override here explicitly as the method in super class FilterBase might do a KeyValue recreate.
   // See HBASE-12068
   @Override
   public Cell transformCell(Cell v) {
     return v;
   }
 
   // returns an array of heterogeneous objects
   public static ArrayList<Object> extractArguments(ArrayList<byte []> filterArguments) {
     Preconditions.checkArgument(filterArguments.size() == 2,
                                 "Expected 2 but got: %s", filterArguments.size());
     CompareOp compareOp = ParseFilter.createCompareOp(filterArguments.get(0));
     ByteArrayComparable comparator = ParseFilter.createComparator(
       ParseFilter.removeQuotesFromByteArray(filterArguments.get(1)));
 
     if (comparator instanceof RegexStringComparator ||
         comparator instanceof SubstringComparator) {
       if (compareOp != CompareOp.EQUAL &&
           compareOp != CompareOp.NOT_EQUAL) {
         throw new IllegalArgumentException ("A regexstring comparator and substring comparator" +
                                             " can only be used with EQUAL and NOT_EQUAL");
       }
     }
     ArrayList<Object> arguments = new ArrayList<Object>();
     arguments.add(compareOp);
     arguments.add(comparator);
     return arguments;
   }
 
   /**
    * @return A pb instance to represent this instance.
    */
   FilterProtos.CompareFilter convert() {
     FilterProtos.CompareFilter.Builder builder =
       FilterProtos.CompareFilter.newBuilder();
     HBaseProtos.CompareType compareOp = CompareType.valueOf(this.compareOp.name());
     builder.setCompareOp(compareOp);
     if (this.comparator != null) builder.setComparator(ProtobufUtil.toComparator(this.comparator));
     return builder.build();
   }
 
   /**
    *
    * @param o
    * @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 CompareFilter)) return false;
 
     CompareFilter other = (CompareFilter)o;
     return this.getOperator().equals(other.getOperator()) &&
       (this.getComparator() == other.getComparator()
         || this.getComparator().areSerializedFieldsEqual(other.getComparator()));
   }
 
   @Override
   public String toString() {
     return String.format("%s (%s, %s)",
         this.getClass().getSimpleName(),
         this.compareOp.name(),
         Bytes.toStringBinary(this.comparator.getValue()));
   }
 
   @Override
   public boolean equals(Object obj) {
     return obj instanceof Filter && areSerializedFieldsEqual((Filter) obj);
   }
 
   @Override
   public int hashCode() {
     return Objects.hash(this.getComparator(), this.getOperator());
   }
 }