Clover coverage report - PMD - 3.7 Coverage timestamp: Wed May 31 2006 09:25:59 EDT FRAMES NO FRAMES |
file stats: | LOC: | 131 |  | Methods: | 7
| NCLOC: | 88 |  | Classes: | 1
Source file | Conditionals | Statements | Methods | TOTAL
ConfusingTernary.java | 20.8% | 34.3% | 85.7% | 34.8% |

1 |  | /**
2 |  | * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
3 |  | */
4 |  | package net.sourceforge.pmd.rules.design;
5 |  |
6 |  | import net.sourceforge.pmd.AbstractRule;
7 |  | import net.sourceforge.pmd.ast.ASTConditionalAndExpression;
8 |  | import net.sourceforge.pmd.ast.ASTConditionalExpression;
9 |  | import net.sourceforge.pmd.ast.ASTConditionalOrExpression;
10 |  | import net.sourceforge.pmd.ast.ASTEqualityExpression;
11 |  | import net.sourceforge.pmd.ast.ASTExpression;
12 |  | import net.sourceforge.pmd.ast.ASTIfStatement;
13 |  | import net.sourceforge.pmd.ast.ASTPrimaryExpression;
14 |  | import net.sourceforge.pmd.ast.ASTPrimaryPrefix;
15 |  | import net.sourceforge.pmd.ast.ASTUnaryExpressionNotPlusMinus;
16 |  | import net.sourceforge.pmd.ast.SimpleNode;
17 |  |
18 |  | /**
19 |  | * if (x != y) { diff(); } else { same(); } and<br>
20 |  | * (!x ? diff() : same());.
21 |  | * <p/>
22 |  | * XPath can handle the easy cases, e.g.:<pre>
23 |  | * //IfStatement[
24 |  | * Statement[2]
25 |  | * and Expression[
26 |  | * EqualityExpression[@Image="!="] or
27 |  | * UnaryExpressionNotPlusMinus[@Image="!"]]]
28 |  | * </pre>
29 |  | * but "&amp;&amp;" and "||" are difficult, since we need a match
30 |  | * for <i>all</i> children instead of just one. This can be done by
31 |  | * using a double-negative, e.g.:<pre>
32 |  | * not(*[not(<i>matchme</i>)])
33 |  | * </pre>
34 |  | * Still, XPath is unable to handle arbitrarily nested cases, since it
35 |  | * lacks recursion, e.g.:<pre>
36 |  | * if (((x != !y)) || !(x)) { diff(); } else { same(); }
37 |  | * </pre>
38 |  | */
39 |  | public class ConfusingTernary extends AbstractRule {
40 |  |
41 | 0 | public Object visit(ASTIfStatement node, Object data) {
42 |  | // look for "if (match) ..; else .."
43 | 0 | if (node.jjtGetNumChildren() == 3) {
44 | 0 | SimpleNode inode = (SimpleNode) node.jjtGetChild(0);
45 | 0 | if (inode instanceof ASTExpression &&
46 |  | inode.jjtGetNumChildren() == 1) {
47 | 0 | SimpleNode jnode = (SimpleNode) inode.jjtGetChild(0);
48 | 0 | if (isMatch(jnode)) {
49 | 0 | addViolation(data, node);
50 |  | }
51 |  | }
52 |  | }
53 | 0 | return super.visit(node, data);
54 |  | }
55 |  |
56 | 2 | public Object visit(ASTConditionalExpression node, Object data) {
57 |  | // look for "match ? .. : .."
58 | 2 | if (node.jjtGetNumChildren() > 0) {
59 | 2 | SimpleNode inode = (SimpleNode) node.jjtGetChild(0);
60 | 2 | if (isMatch(inode)) {
61 | 1 | addViolation(data, node);
62 |  | }
63 |  | }
64 | 2 | return super.visit(node, data);
65 |  | }
66 |  |
67 |  | // recursive!
68 | 2 | private static boolean isMatch(SimpleNode node) {
69 | 2 | return
70 |  | isUnaryNot(node) ||
71 |  | isNotEquals(node) ||
72 |  | isConditionalWithAllMatches(node) ||
73 |  | isParenthesisAroundMatch(node);
74 |  | }
75 |  |
76 | 2 | private static boolean isUnaryNot(SimpleNode node) {
77 |  | // look for "!x"
78 | 2 | return
79 |  | node instanceof ASTUnaryExpressionNotPlusMinus &&
80 |  | "!".equals(node.getImage());
81 |  | }
82 |  |
83 | 2 | private static boolean isNotEquals(SimpleNode node) {
84 |  | // look for "x != y"
85 | 2 | return
86 |  | node instanceof ASTEqualityExpression &&
87 |  | "!=".equals(node.getImage());
88 |  | }
89 |  |
90 | 1 | private static boolean isConditionalWithAllMatches(SimpleNode node) {
91 |  | // look for "match && match" or "match || match"
92 | 1 | if (!(node instanceof ASTConditionalAndExpression) &&
93 |  | !(node instanceof ASTConditionalOrExpression)) {
94 | 1 | return false;
95 |  | }
96 | 0 | int i_max = node.jjtGetNumChildren();
97 | 0 | if (i_max <= 0) {
98 | 0 | return false;
99 |  | }
100 | 0 | for (int i = 0; i < i_max; i++) {
101 | 0 | SimpleNode inode = (SimpleNode) node.jjtGetChild(i);
102 |  | // recurse!
103 | 0 | if (!isMatch(inode)) {
104 | 0 | return false;
105 |  | }
106 |  | }
107 |  | // all match
108 | 0 | return true;
109 |  | }
110 |  |
111 | 1 | private static boolean isParenthesisAroundMatch(SimpleNode node) {
112 |  | // look for "(match)"
113 | 1 | if (!(node instanceof ASTPrimaryExpression) ||
114 |  | (node.jjtGetNumChildren() != 1)) {
115 | 1 | return false;
116 |  | }
117 | 0 | SimpleNode inode = (SimpleNode) node.jjtGetChild(0);
118 | 0 | if (!(inode instanceof ASTPrimaryPrefix) ||
119 |  | (inode.jjtGetNumChildren() != 1)) {
120 | 0 | return false;
121 |  | }
122 | 0 | SimpleNode jnode = (SimpleNode) inode.jjtGetChild(0);
123 | 0 | if (!(jnode instanceof ASTExpression) ||
124 |  | (jnode.jjtGetNumChildren() != 1)) {
125 | 0 | return false;
126 |  | }
127 | 0 | SimpleNode knode = (SimpleNode) jnode.jjtGetChild(0);
128 |  | // recurse!
129 | 0 | return isMatch(knode);
130 |  | }
131 |  | }