Add Cyclomatic Complexity implementation for Java

Author: marco-ballario

src/metrics/cyclomatic.rs

@@ -203,7 +203,19 @@ impl Cyclomatic for CppCode {
 
 impl Cyclomatic for PreprocCode {}
 impl Cyclomatic for CcommentCode {}
-impl Cyclomatic for JavaCode {}
+
+impl Cyclomatic for JavaCode {
+    fn compute(node: &Node, stats: &mut Stats) {
+        use Java::*;
+
+        match node.object().kind_id().into() {
+            If | For | While | Case | Catch | TernaryExpression | AMPAMP | PIPEPIPE => {
+                stats.cyclomatic += 1.;
+            }
+            _ => {}
+        }
+    }
+}
 
 #[cfg(test)]
 mod tests {
@@ -406,4 +418,66 @@ mod tests {
             ]
         );
     }
+
+    #[test]
+    fn java_simple_class() {
+        check_metrics!(
+            "
+            public class Example { // +2 (+1 unit space)
+                int a = 1;
+                int b = (a == 1) ? 1 : 0; // +1
+                int c = (a == 2) ? 1 : 0; // +1
+                public void m1() { // +1
+                    if (a == 1) { // +1
+    
+                    }
+                }
+                public void m2() { // +1
+                    if (a == 2) { // +1
+    
+                    }
+                }
+            }",
+            "foo.java",
+            JavaParser,
+            cyclomatic,
+            [(cyclomatic_sum, 8, usize)],
+            [
+                (cyclomatic_average, 2.0), // nspace = 4 (unit, class and 2 methods)
+                (cyclomatic_max, 3.0),
+                (cyclomatic_min, 1.0)
+            ]
+        );
+    }
+
+    #[test]
+    fn java_real_class() {
+        check_metrics!(
+            "
+            public class Matrix { // +2 (+1 unit space)
+                private int[][] m = new int[5][5];
+
+                public void init() { // +1
+                    for (int i = 0; i < m.length; i++) { // +1
+                        for (int j = 0; j < m[i].length; j++) { // +1
+                            if (i == j) { // +1
+                                m[i][j] = i + j;
+                            } else {
+                                m[i][j] = i * j;
+                            }
+                        }
+                    }
+                }
+            }",
+            "foo.java",
+            JavaParser,
+            cyclomatic,
+            [(cyclomatic_sum, 6, usize)],
+            [
+                (cyclomatic_average, 2.0), // nspace = 3 (unit, class and method)
+                (cyclomatic_max, 4.0),
+                (cyclomatic_min, 1.0)
+            ]
+        );
+    }
 }