/**
    *
    * 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.ArrayList;
  
  import org.apache.hadoop.hbase.util.ByteStringer;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  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.CellUtil;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
  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 com.google.common.base.Preconditions;
  import com.google.protobuf.InvalidProtocolBufferException;
  
  /**
   * This filter is used to filter cells based on value. It takes a {@link CompareFilter.CompareOp}
   * operator (equal, greater, not equal, etc), and either a byte [] value or
   * a ByteArrayComparable.
   * <p>
   * If we have a byte [] value then we just do a lexicographic compare. For
   * example, if passed value is 'b' and cell has 'a' and the compare operator
   * is LESS, then we will filter out this cell (return true).  If this is not
   * sufficient (eg you want to deserialize a long and then compare it to a fixed
   * long value), then you can pass in your own comparator instead.
   * <p>
   * You must also specify a family and qualifier.  Only the value of this column
   * will be tested. When using this filter on a 
   * {@link org.apache.hadoop.hbase.CellScanner} with specified
   * inputs, the column to be tested should also be added as input (otherwise
   * the filter will regard the column as missing).
   * <p>
   * To prevent the entire row from being emitted if the column is not found
   * on a row, use {@link #setFilterIfMissing}.
   * Otherwise, if the column is found, the entire row will be emitted only if
   * the value passes.  If the value fails, the row will be filtered out.
   * <p>
   * In order to test values of previous versions (timestamps), set
   * {@link #setLatestVersionOnly} to false. The default is true, meaning that
   * only the latest version's value is tested and all previous versions are ignored.
   * <p>
   * To filter based on the value of all scanned columns, use {@link ValueFilter}.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class SingleColumnValueFilter extends FilterBase {
    private static final Log LOG = LogFactory.getLog(SingleColumnValueFilter.class);
  
    protected byte [] columnFamily;
    protected byte [] columnQualifier;
    protected CompareOp compareOp;
    protected ByteArrayComparable comparator;
    protected boolean foundColumn = false;
    protected boolean matchedColumn = false;
    protected boolean filterIfMissing = false;
    protected boolean latestVersionOnly = true;
  
    /**
     * Constructor for binary compare of the value of a single column.  If the
     * column is found and the condition passes, all columns of the row will be
     * emitted.  If the condition fails, the row will not be emitted.
     * <p>
     * Use the filterIfColumnMissing flag to set whether the rest of the columns
     * in a row will be emitted if the specified column to check is not found in
     * the row.
     *
     * @param family name of column family
     * @param qualifier name of column qualifier
     * @param compareOp operator
     * @param value value to compare column values against
     */
    public SingleColumnValueFilter(final byte [] family, final byte [] qualifier,
       final CompareOp compareOp, final byte[] value) {
     this(family, qualifier, compareOp, new BinaryComparator(value));
   }
 
   /**
    * Constructor for binary compare of the value of a single column.  If the
    * column is found and the condition passes, all columns of the row will be
    * emitted.  If the condition fails, the row will not be emitted.
    * <p>
    * Use the filterIfColumnMissing flag to set whether the rest of the columns
    * in a row will be emitted if the specified column to check is not found in
    * the row.
    *
    * @param family name of column family
    * @param qualifier name of column qualifier
    * @param compareOp operator
    * @param comparator Comparator to use.
    */
   public SingleColumnValueFilter(final byte [] family, final byte [] qualifier,
       final CompareOp compareOp, final ByteArrayComparable comparator) {
     this.columnFamily = family;
     this.columnQualifier = qualifier;
     this.compareOp = compareOp;
     this.comparator = comparator;
   }
 
   /**
    * Constructor for protobuf deserialization only.
    * @param family
    * @param qualifier
    * @param compareOp
    * @param comparator
    * @param filterIfMissing
    * @param latestVersionOnly
    */
   protected SingleColumnValueFilter(final byte[] family, final byte[] qualifier,
       final CompareOp compareOp, ByteArrayComparable comparator, final boolean filterIfMissing,
       final boolean latestVersionOnly) {
     this(family, qualifier, compareOp, comparator);
     this.filterIfMissing = filterIfMissing;
     this.latestVersionOnly = latestVersionOnly;
   }
 
   /**
    * @return operator
    */
   public CompareOp getOperator() {
     return compareOp;
   }
 
   /**
    * @return the comparator
    */
   public ByteArrayComparable getComparator() {
     return comparator;
   }
 
   /**
    * @return the family
    */
   public byte[] getFamily() {
     return columnFamily;
   }
 
   /**
    * @return the qualifier
    */
   public byte[] getQualifier() {
     return columnQualifier;
   }
 
   @Override
   public ReturnCode filterKeyValue(Cell c) {
     if (this.matchedColumn) {
       // We already found and matched the single column, all keys now pass
       return ReturnCode.INCLUDE;
     } else if (this.latestVersionOnly && this.foundColumn) {
       // We found but did not match the single column, skip to next row
       return ReturnCode.NEXT_ROW;
     }
     if (!CellUtil.matchingColumn(c, this.columnFamily, this.columnQualifier)) {
       return ReturnCode.INCLUDE;
     }
     foundColumn = true;
     if (filterColumnValue(c.getValueArray(), c.getValueOffset(), c.getValueLength())) {
       return this.latestVersionOnly? ReturnCode.NEXT_ROW: ReturnCode.INCLUDE;
     }
     this.matchedColumn = true;
     return ReturnCode.INCLUDE;
   }
 
   // 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;
   }
 
   private boolean filterColumnValue(final byte [] data, final int offset,
       final int length) {
     int compareResult = this.comparator.compareTo(data, offset, length);
     switch (this.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
   public boolean filterRow() {
     // If column was found, return false if it was matched, true if it was not
     // If column not found, return true if we filter if missing, false if not
     return this.foundColumn? !this.matchedColumn: this.filterIfMissing;
   }
   
   @Override
   public boolean hasFilterRow() {
     return true;
   }
 
   @Override
   public void reset() {
     foundColumn = false;
     matchedColumn = false;
   }
 
   /**
    * Get whether entire row should be filtered if column is not found.
    * @return true if row should be skipped if column not found, false if row
    * should be let through anyways
    */
   public boolean getFilterIfMissing() {
     return filterIfMissing;
   }
 
   /**
    * Set whether entire row should be filtered if column is not found.
    * <p>
    * If true, the entire row will be skipped if the column is not found.
    * <p>
    * If false, the row will pass if the column is not found.  This is default.
    * @param filterIfMissing flag
    */
   public void setFilterIfMissing(boolean filterIfMissing) {
     this.filterIfMissing = filterIfMissing;
   }
 
   /**
    * Get whether only the latest version of the column value should be compared.
    * If true, the row will be returned if only the latest version of the column
    * value matches. If false, the row will be returned if any version of the
    * column value matches. The default is true.
    * @return return value
    */
   public boolean getLatestVersionOnly() {
     return latestVersionOnly;
   }
 
   /**
    * Set whether only the latest version of the column value should be compared.
    * If true, the row will be returned if only the latest version of the column
    * value matches. If false, the row will be returned if any version of the
    * column value matches. The default is true.
    * @param latestVersionOnly flag
    */
   public void setLatestVersionOnly(boolean latestVersionOnly) {
     this.latestVersionOnly = latestVersionOnly;
   }
 
   public static Filter createFilterFromArguments(ArrayList<byte []> filterArguments) {
     Preconditions.checkArgument(filterArguments.size() == 4 || filterArguments.size() == 6,
                                 "Expected 4 or 6 but got: %s", filterArguments.size());
     byte [] family = ParseFilter.removeQuotesFromByteArray(filterArguments.get(0));
     byte [] qualifier = ParseFilter.removeQuotesFromByteArray(filterArguments.get(1));
     CompareOp compareOp = ParseFilter.createCompareOp(filterArguments.get(2));
     ByteArrayComparable comparator = ParseFilter.createComparator(
       ParseFilter.removeQuotesFromByteArray(filterArguments.get(3)));
 
     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");
       }
     }
 
     SingleColumnValueFilter filter = new SingleColumnValueFilter(family, qualifier,
                                                                  compareOp, comparator);
 
     if (filterArguments.size() == 6) {
       boolean filterIfMissing = ParseFilter.convertByteArrayToBoolean(filterArguments.get(4));
       boolean latestVersionOnly = ParseFilter.convertByteArrayToBoolean(filterArguments.get(5));
       filter.setFilterIfMissing(filterIfMissing);
       filter.setLatestVersionOnly(latestVersionOnly);
     }
     return filter;
   }
 
   FilterProtos.SingleColumnValueFilter convert() {
     FilterProtos.SingleColumnValueFilter.Builder builder =
       FilterProtos.SingleColumnValueFilter.newBuilder();
     if (this.columnFamily != null) {
       builder.setColumnFamily(ByteStringer.wrap(this.columnFamily));
     }
     if (this.columnQualifier != null) {
       builder.setColumnQualifier(ByteStringer.wrap(this.columnQualifier));
     }
     HBaseProtos.CompareType compareOp = CompareType.valueOf(this.compareOp.name());
     builder.setCompareOp(compareOp);
     builder.setComparator(ProtobufUtil.toComparator(this.comparator));
     builder.setFilterIfMissing(this.filterIfMissing);
     builder.setLatestVersionOnly(this.latestVersionOnly);
 
     return builder.build();
   }
 
   /**
    * @return The filter serialized using pb
    */
   @Override
   public byte [] toByteArray() {
     return convert().toByteArray();
   }
 
   /**
    * @param pbBytes A pb serialized {@link SingleColumnValueFilter} instance
    * @return An instance of {@link SingleColumnValueFilter} made from <code>bytes</code>
    * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
    * @see #toByteArray
    */
   public static SingleColumnValueFilter parseFrom(final byte [] pbBytes)
   throws DeserializationException {
     FilterProtos.SingleColumnValueFilter proto;
     try {
       proto = FilterProtos.SingleColumnValueFilter.parseFrom(pbBytes);
     } catch (InvalidProtocolBufferException e) {
       throw new DeserializationException(e);
     }
 
     final CompareOp compareOp =
       CompareOp.valueOf(proto.getCompareOp().name());
     final ByteArrayComparable comparator;
     try {
       comparator = ProtobufUtil.toComparator(proto.getComparator());
     } catch (IOException ioe) {
       throw new DeserializationException(ioe);
     }
 
     return new SingleColumnValueFilter(proto.hasColumnFamily() ? proto.getColumnFamily()
         .toByteArray() : null, proto.hasColumnQualifier() ? proto.getColumnQualifier()
         .toByteArray() : null, compareOp, comparator, proto.getFilterIfMissing(), proto
         .getLatestVersionOnly());
   }
 
   /**
    * @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 SingleColumnValueFilter)) return false;
 
     SingleColumnValueFilter other = (SingleColumnValueFilter)o;
     return Bytes.equals(this.getFamily(), other.getFamily())
       && Bytes.equals(this.getQualifier(), other.getQualifier())
       && this.compareOp.equals(other.compareOp)
       && this.getComparator().areSerializedFieldsEqual(other.getComparator())
       && this.getFilterIfMissing() == other.getFilterIfMissing()
       && this.getLatestVersionOnly() == other.getLatestVersionOnly();
   }
 
   /**
    * The only CF this filter needs is given column family. So, it's the only essential
    * column in whole scan. If filterIfMissing == false, all families are essential,
    * because of possibility of skipping the rows without any data in filtered CF.
    */
   @Override
   public boolean isFamilyEssential(byte[] name) {
     return !this.filterIfMissing || Bytes.equals(name, this.columnFamily);
   }
 
   @Override
   public String toString() {
     return String.format("%s (%s, %s, %s, %s)",
         this.getClass().getSimpleName(), Bytes.toStringBinary(this.columnFamily),
         Bytes.toStringBinary(this.columnQualifier), this.compareOp.name(),
         Bytes.toStringBinary(this.comparator.getValue()));
   }
 }