content: /*
   * 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.cassandra.cql3.constraints;
  
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.cassandra.cql3.Operator;
  import org.apache.cassandra.cql3.functions.types.ParseUtils;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.AsciiType;
  import org.apache.cassandra.db.marshal.UTF8Type;
  import org.apache.cassandra.schema.ColumnMetadata;
  
  import static java.lang.String.format;
  import static org.apache.cassandra.cql3.Operator.EQ;
  import static org.apache.cassandra.cql3.Operator.NEQ;
  
  public class RegexpConstraint extends ConstraintFunction
  {
      public static final String FUNCTION_NAME = "REGEXP";
      private static final List<AbstractType<?>> SUPPORTED_TYPES = List.of(UTF8Type.instance, AsciiType.instance);
      private static final List<Operator> ALLOWED_FUNCTION_OPERATORS = List.of(EQ, NEQ);
  
      private Pattern pattern;
  
      public RegexpConstraint(List<String> args)
      {
          super(FUNCTION_NAME, args);
      }
  
      @Override
      protected void internalEvaluate(AbstractType<?> valueType, Operator relationType, String regexp, ByteBuffer columnValue)
      {
          assert pattern != null;
          Matcher matcher = pattern.matcher(valueType.getString(columnValue));
  
          switch (relationType)
          {
              case EQ:
                  if (!matcher.matches())
                      throw new ConstraintViolationException(format("Value does not match regular expression %s", regexp));
                  break;
              case NEQ:
                  if (matcher.matches())
                      throw new ConstraintViolationException(format("Value does match regular expression %s", regexp));
                  break;
              default:
                  throw new IllegalStateException("Unsupported operator: " + relationType);
          }
      }
  
      @Override
      public List<AbstractType<?>> getSupportedTypes()
      {
          return SUPPORTED_TYPES;
      }
  
      @Override
      public List<Operator> getSupportedOperators()
      {
          return ALLOWED_FUNCTION_OPERATORS;
      }
  
      @Override
      public void validate(ColumnMetadata columnMetadata, String regexp) throws InvalidConstraintDefinitionException
      {
          super.validate(columnMetadata, regexp);
          try
          {
              // compilation of a regexp every single time upon evaluation is not performance friendly
              // so we "cache" the compiled regexp for further reuse upon actual validation
              pattern = Pattern.compile(ParseUtils.unquote(regexp));
          }
          catch (Exception e)
          {
              throw new InvalidConstraintDefinitionException(format("String '%s' is not a valid regular expression", ParseUtils.unquote(regexp)));
          }
      }
  
      @Override
      public boolean equals(Object o)
      {
          if (this == o)
              return true;
  
          if (!(o instanceof RegexpConstraint))
              return false;
  
          RegexpConstraint other = (RegexpConstraint) o;
  
          return columnName.equals(other.columnName);
      }
  }
  