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
   * <p/>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p/>
   * 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.atlas.impala.hook;
  
  import org.apache.atlas.impala.model.ImpalaOperationType;
  import org.apache.commons.lang.StringUtils;
  
  import java.util.regex.Pattern;
  
  /**
   * Parse an Impala query text and output the impala operation type
   */
  public class ImpalaOperationParser {
      private static final Pattern COMMENT_PATTERN = Pattern.compile("/\\*.*?\\*/", Pattern.DOTALL);
  
      private static final Pattern CREATE_VIEW_PATTERN =
              Pattern.compile("^[ ]*\\bcreate\\b.*\\bview\\b.*", Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
  
      private static final Pattern CREATE_TABLE_AS_SELECT_PATTERN =
              Pattern.compile("^[ ]*\\bcreate\\b.*\\btable\\b.*\\bas\\b.*\\bselect\\b.*", Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
  
      private static final Pattern ALTER_VIEW_AS_SELECT_PATTERN =
              Pattern.compile("^[ ]*\\balter\\b.*\\bview\\b.*\\bas.*\\bselect\\b.*", Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
  
      private static final Pattern INSERT_SELECT_FROM_PATTERN =
              Pattern.compile("^[ ]*\\binsert\\b.*\\b(into|overwrite)\\b.*\\bselect\\b.*\\bfrom\\b.*", Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
  
      private static final Pattern WITH_CLAUSE_INSERT_SELECT_FROM_PATTERN =
              Pattern.compile("^[ ]*(\\bwith\\b.*)?\\s*\\binsert\\b.*\\b(into|overwrite)\\b.*\\bselect\\b.*\\bfrom\\b.*", Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
  
      private ImpalaOperationParser() {}
  
      public static ImpalaOperationType getImpalaOperationType(String queryText) {
          // Impala does no generate lineage record for command "LOAD DATA IN PATH"
          String queryTextWithNoComments = COMMENT_PATTERN.matcher(queryText).replaceAll("");
          if (doesMatch(queryTextWithNoComments, CREATE_VIEW_PATTERN)) {
              return ImpalaOperationType.CREATEVIEW;
          } else if (doesMatch(queryTextWithNoComments, CREATE_TABLE_AS_SELECT_PATTERN)) {
              return ImpalaOperationType.CREATETABLE_AS_SELECT;
          } else if (doesMatch(queryTextWithNoComments, ALTER_VIEW_AS_SELECT_PATTERN)) {
              return ImpalaOperationType.ALTERVIEW_AS;
          } else if (doesMatch(queryTextWithNoComments, INSERT_SELECT_FROM_PATTERN)) {
              return ImpalaOperationType.QUERY;
          } else if (doesMatch(queryTextWithNoComments, WITH_CLAUSE_INSERT_SELECT_FROM_PATTERN)) {
              return ImpalaOperationType.QUERY_WITH_CLAUSE;
          }
  
          return ImpalaOperationType.UNKNOWN;
      }
  
      public static ImpalaOperationType getImpalaOperationSubType(ImpalaOperationType operationType, String queryText) {
          if (operationType == ImpalaOperationType.QUERY) {
              if (StringUtils.containsIgnoreCase(queryText, "insert into")) {
                  return ImpalaOperationType.INSERT;
              } else if (StringUtils.containsIgnoreCase(queryText, "insert overwrite")) {
                  return ImpalaOperationType.INSERT_OVERWRITE;
              }
          }
  
          return ImpalaOperationType.UNKNOWN;
      }
  
      private static boolean doesMatch(final String queryText, final Pattern pattern) {
          return pattern.matcher(queryText).matches();
      }
  }
  