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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 }