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Java > Open Source Codes > net > sourceforge > pmd > rules > strings > AppendCharacterWithChar


1 /**
2  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
3  */
4 package net.sourceforge.pmd.rules.strings;
5
6 import net.sourceforge.pmd.AbstractRule;
7 import net.sourceforge.pmd.ast.ASTBlockStatement;
8 import net.sourceforge.pmd.ast.ASTLiteral;
9
10 import java.util.regex.Pattern JavaDoc;
11 import java.util.regex.Matcher JavaDoc;
12
13 /**
14  * This rule finds the following:
15  * <p/>
16  * <pre>
17  * StringBuffer.append(&quot;c&quot;); // appends a
18  * single character
19  * </pre>
20  * <p/>
21  * It is preferable to use StringBuffer.append('c'); // appends a single
22  * character Implementation of PMD RFE 1373863
23  */
24 public class AppendCharacterWithChar extends AbstractRule {
25
26     private static final Pattern JavaDoc REGEX = Pattern.compile("\"[\\\\]?[\\s\\S]\"");
27
28     public Object JavaDoc visit(ASTLiteral node, Object JavaDoc data) {
29         ASTBlockStatement bs = (ASTBlockStatement) node
30                 .getFirstParentOfType(ASTBlockStatement.class);
31         if (bs == null) {
32             return data;
33         }
34
35         String JavaDoc str = node.getImage();
36         if (str == null || str.length() < 3 || str.length() > 4) {
37             return data;
38         }
39
40         Matcher JavaDoc matcher = REGEX.matcher(str);
41         if (matcher.find()) {
42             if (!InefficientStringBuffering.isInStringBufferOperation(node, 8, "append")) {
43                 return data;
44             }
45             addViolation(data, node);
46         }
47         return data;
48     }
49 }
50
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