/**
* 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.drill.exec.planner.sql.parser;
import org.apache.drill.exec.planner.sql.handlers.AbstractSqlHandler;
import org.apache.drill.exec.planner.sql.handlers.SqlHandlerConfig;
import org.apache.drill.exec.planner.sql.handlers.UseSchemaHandler;
import org.eigenbase.sql.SqlCall;
import org.eigenbase.sql.SqlIdentifier;
import org.eigenbase.sql.SqlKind;
import org.eigenbase.sql.SqlLiteral;
import org.eigenbase.sql.SqlNode;
import org.eigenbase.sql.SqlOperator;
import org.eigenbase.sql.SqlSpecialOperator;
import org.eigenbase.sql.SqlWriter;
import org.eigenbase.sql.parser.SqlParserPos;
import java.util.Collections;
import java.util.List;
/**
* Sql parser tree node to represent <code>USE SCHEMA</code> statement.
*/
public class SqlUseSchema extends DrillSqlCall {
public static final SqlSpecialOperator OPERATOR =
new SqlSpecialOperator("USE_SCHEMA", SqlKind.OTHER){
@Override
public SqlCall createCall(SqlLiteral functionQualifier, SqlParserPos pos, SqlNode... operands) {
return new SqlUseSchema(pos, (SqlIdentifier) operands[0]);
}
};
private SqlIdentifier schema;
public SqlUseSchema(SqlParserPos pos, SqlIdentifier schema) {
super(pos);
this.schema = schema;
assert schema != null;
}
@Override
public List<SqlNode> getOperandList() {
return Collections.singletonList((SqlNode)schema);
}
@Override
public SqlOperator getOperator() {
return OPERATOR;
}
@Override
public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
writer.keyword("USE");
schema.unparse(writer, leftPrec, rightPrec);
}
@Override
public AbstractSqlHandler getSqlHandler(SqlHandlerConfig config) {
return new UseSchemaHandler(config.getContext());
}
/**
* Get the schema name. A schema identifier can contain more than one level of schema.
* Ex: "dfs.home" identifier contains two levels "dfs" and "home".
* @return schemas combined with "."
*/
public String getSchema() {
return schema.toString();
}
}