001/*
002MIT License
003
004Copyright (c) 2020 FBSQL Team
005
006Permission is hereby granted, free of charge, to any person obtaining a copy
007of this software and associated documentation files (the "Software"), to deal
008in the Software without restriction, including without limitation the rights
009to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010copies of the Software, and to permit persons to whom the Software is
011furnished to do so, subject to the following conditions:
012
013The above copyright notice and this permission notice shall be included in all
014copies or substantial portions of the Software.
015
016THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
022SOFTWARE.
023
024Home:   https://fbsql.github.io
025E-Mail: fbsql.team@gmail.com
026*/
027
028package org.fbsql.antlr4.parser;
029
030import javax.servlet.ServletConfig;
031
032import org.antlr.v4.runtime.CharStreams;
033import org.antlr.v4.runtime.CommonTokenStream;
034import org.antlr.v4.runtime.Lexer;
035import org.antlr.v4.runtime.tree.ParseTree;
036import org.antlr.v4.runtime.tree.ParseTreeWalker;
037import org.fbsql.antlr4.generated.FbsqlBaseListener;
038import org.fbsql.antlr4.generated.FbsqlLexer;
039import org.fbsql.antlr4.generated.FbsqlParser;
040import org.fbsql.antlr4.generated.FbsqlParser.Connection_aliasContext;
041import org.fbsql.servlet.DbServlet;
042import org.fbsql.servlet.SqlParseUtils;
043import org.fbsql.servlet.StringUtils;
044
045/*
046 * ANTLR4 grammar:
047 *
048 * switch_to_stmt
049 *  : SWITCH TO connection_alias
050 *  ;
051 */
052public class ParseStmtSwitchTo {
053
054        /**
055         * DTO (Data Transfer Object) that holds RDBMS connection meta data
056         * Field values comes from parsing of "SWITCH TO" SQL statement
057         * 
058         * @see SqlParseUtils#parseConnectStatement(String)
059         */
060        public class StmtSwitchTo {
061
062                /**
063                 * Value from "AS" clause
064                 */
065                public String instanceName;
066
067                @Override
068                public String toString() {
069                        return "StmtSwitchTo [instanceName=" + instanceName + "]";
070                }
071        }
072
073        /**
074         * StmtConnectTo transfer object
075         */
076        private StmtSwitchTo st;
077
078        public ParseStmtSwitchTo() {
079                st = new StmtSwitchTo();
080        }
081
082        /**
083         * SWITCH TO Statement parser
084         *
085         * E.g.: SWITCH TO mycon
086         *
087         * @param sql
088         * @return
089         */
090        public StmtSwitchTo parse(ServletConfig servletConfig, String sql) {
091                Lexer       lexer  = new FbsqlLexer(CharStreams.fromString(sql));
092                FbsqlParser parser = new FbsqlParser(new CommonTokenStream(lexer));
093                ParseTree   tree   = parser.switch_to_stmt();
094
095                ParseTreeWalker.DEFAULT.walk(new FbsqlBaseListener() {
096
097                        @Override
098                        public void enterConnection_alias(Connection_aliasContext ctx) {
099                                st.instanceName = StringUtils.unquote(ctx.getText());
100                        }
101
102                }, tree);
103
104                if (DbServlet.DEBUG)
105                        System.out.println(st);
106
107                return st;
108        }
109}
110
111/*
112Please contact FBSQL Team by E-Mail fbsql.team@gmail.com
113or visit https://fbsql.github.io if you need additional
114information or have any questions.
115*/
116
117/* EOF */