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.sql.parser.postgresql.parser;
19
20 import org.antlr.v4.runtime.CharStream;
21 import org.antlr.v4.runtime.Lexer;
22
23 import java.util.ArrayDeque;
24 import java.util.Deque;
25
26 /**
27 * SQL lexer base for PostgreSQL.
28 */
29 public abstract class PostgreSQLLexerBase extends Lexer {
30
31 private final Deque<String> tags = new ArrayDeque<>();
32
33 protected PostgreSQLLexerBase(final CharStream input) {
34 super(input);
35 }
36
37 /**
38 * Push tag.
39 */
40 public void pushTag() {
41 tags.push(getText());
42 }
43
44 /**
45 * Judge is tag.
46 *
47 * @return is tag
48 */
49 public boolean isTag() {
50 return getText().equals(tags.peek());
51 }
52
53 /**
54 * Pop tag.
55 */
56 public void popTag() {
57 tags.pop();
58 }
59 }