1 /*
2 * Copyright 2002-2008 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.batch.item.database;
18
19 import java.util.Map;
20 import java.util.HashMap;
21 import java.util.List;
22
23 /**
24 * Helper methods for SQL statement parameter parsing.
25 *
26 * Only intended for internal use.
27 *
28 * @author Thomas Risberg
29 * @author Juergen Hoeller
30 * @since 2.0
31 */
32 public class JdbcParameterUtils {
33
34 /**
35 * Count the occurrences of the character placeholder in an SQL string
36 * <code>sql</code>. The character placeholder is not counted if it appears
37 * within a literal, that is, surrounded by single or double quotes. This method will
38 * count traditional placeholders in the form of a question mark ('?') as well as
39 * named parameters indicated with a leading ':' or '&'.
40 *
41 * The code for this method is taken from an early version of the
42 * {@link org.springframework.jdbc.core.namedparam.NamedParameterUtils}
43 * class. That method was later removed after some refactoring, but the code
44 * is useful here for the Spring Batch project. The code has been altered to better
45 * suite the batch processing requirements.
46 *
47 * @param sql String to search in. Returns 0 if the given String is <code>null</code>.
48 */
49 public static int countParameterPlaceholders(String sql, List<String> namedParameterHolder ) {
50 if (sql == null) {
51 return 0;
52 }
53
54 char[] statement = sql.toCharArray();
55 boolean withinQuotes = false;
56 Map<String, StringBuilder> namedParameters = new HashMap<String, StringBuilder>();
57 char currentQuote = '-';
58 int parameterCount = 0;
59 int i = 0;
60 while (i < statement.length) {
61 if (withinQuotes) {
62 if (statement[i] == currentQuote) {
63 withinQuotes = false;
64 currentQuote = '-';
65 }
66 }
67 else {
68 if (statement[i] == '"' || statement[i] == '\'') {
69 withinQuotes = true;
70 currentQuote = statement[i];
71 }
72 else {
73 if (statement[i] == ':' || statement[i] == '&') {
74 int j = i + 1;
75 StringBuilder parameter = new StringBuilder();
76 while (j < statement.length && parameterNameContinues(statement, j)) {
77 parameter.append(statement[j]);
78 j++;
79 }
80 if (j - i > 1) {
81 if (!namedParameters.containsKey(parameter.toString())) {
82 parameterCount++;
83 namedParameters.put(parameter.toString(), parameter);
84 i = j - 1;
85 }
86 }
87 }
88 else {
89 if (statement[i] == '?') {
90 parameterCount++;
91 }
92 }
93 }
94 }
95 i++;
96 }
97 if (namedParameterHolder != null) {
98 namedParameterHolder.addAll(namedParameters.keySet());
99 }
100 return parameterCount;
101 }
102
103 /**
104 * Determine whether a parameter name continues at the current position,
105 * that is, does not end delimited by any whitespace character yet.
106 * @param statement the SQL statement
107 * @param pos the position within the statement
108 */
109 private static boolean parameterNameContinues(char[] statement, int pos) {
110 return (statement[pos] != ' ' && statement[pos] != ',' && statement[pos] != ')' &&
111 statement[pos] != '"' && statement[pos] != '\'' && statement[pos] != '|' &&
112 statement[pos] != ';' && statement[pos] != '\n' && statement[pos] != '\r');
113 }
114
115 }