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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.shardingsphere.proxy.backend.mysql.handler.admin.executor;
19  
20  import lombok.RequiredArgsConstructor;
21  import org.apache.shardingsphere.authority.checker.AuthorityChecker;
22  import org.apache.shardingsphere.authority.rule.AuthorityRule;
23  import org.apache.shardingsphere.infra.exception.core.ShardingSpherePreconditions;
24  import org.apache.shardingsphere.infra.exception.dialect.exception.syntax.database.UnknownDatabaseException;
25  import org.apache.shardingsphere.proxy.backend.context.ProxyContext;
26  import org.apache.shardingsphere.proxy.backend.handler.admin.executor.DatabaseAdminExecutor;
27  import org.apache.shardingsphere.proxy.backend.session.ConnectionSession;
28  import org.apache.shardingsphere.sql.parser.sql.common.statement.dal.UseStatement;
29  import org.apache.shardingsphere.sql.parser.sql.common.util.SQLUtils;
30  
31  /**
32   * Use database executor.
33   */
34  @RequiredArgsConstructor
35  public final class UseDatabaseExecutor implements DatabaseAdminExecutor {
36      
37      private final UseStatement useStatement;
38      
39      @Override
40      public void execute(final ConnectionSession connectionSession) {
41          String databaseName = SQLUtils.getExactlyValue(useStatement.getSchema());
42          AuthorityRule authorityRule = ProxyContext.getInstance().getContextManager().getMetaDataContexts().getMetaData().getGlobalRuleMetaData().getSingleRule(AuthorityRule.class);
43          AuthorityChecker authorityChecker = new AuthorityChecker(authorityRule, connectionSession.getGrantee());
44          ShardingSpherePreconditions.checkState(ProxyContext.getInstance().databaseExists(databaseName) && authorityChecker.isAuthorized(databaseName),
45                  () -> new UnknownDatabaseException(databaseName));
46          connectionSession.setCurrentDatabase(databaseName);
47      }
48  }