Add PCN metric

metrics/ast.py

@@ -347,6 +347,17 @@ def varcomp(tlist: list[tuple[Any, javalang.tree.ClassDeclaration]]) -> float:
     return (parts / variables) if variables != 0 else 0
 
 
+def pcn(tlist: list[tuple[Any, javalang.tree.ClassDeclaration]]) -> int:
+    """Return number of words in the name of a class.
+    r:type: int
+    """
+    classname = tlist[0][1].name
+    # By naming convention Java classes names use PascalCase.
+    # Nevertheless, this metric considers both PascalCasse and camelCase naming conventions.
+    words = re.findall(r'[A-Z]?[a-z]+|[A-Z]+(?=[A-Z]|$)', classname)
+    return len(words)
+
+
 def nop(tlist: list[tuple[Any, javalang.tree.ClassDeclaration]]) -> int:
     """Return number of polymorphic methods in main class.
     Methods of nested classes are skipped.
@@ -419,6 +430,8 @@ class NotClassError(Exception):
                              f'Number of Class Annotations\n')
                 metric.write(f'varcomp {varcomp(tree_class)} '
                              f'Average number of parts in variable names\n')
+                metric.write(f'pcn {pcn(tree_class)} '
+                             f'Number of words in the name of a class\n')
                 metric.write(f'mhf {mhf(tree_class)} '
                              f'Method Hiding Factor (MHF), which is the ratio of private \
                              and protected methods to total methods\n')

tests/metrics/test-ast.sh

@@ -49,6 +49,7 @@ stdout=$2
     grep "final 1 " "${temp}/stdout"
     grep "noca 1 " "${temp}/stdout"
     grep "varcomp 2.75 " "${temp}/stdout"
+    grep "pcn 1" "${temp}/stdout"
     grep "mhf 1.0 " "${temp}/stdout"
     grep "smhf 0 " "${temp}/stdout"
     grep "ahf 0.25 " "${temp}/stdout"

tests/steps/test-measure-file.sh

@@ -45,7 +45,7 @@ EOT
     set -x
     test "$(echo "${msg}" | grep -c "sum=0")" = 0
     all=$(find "${temp}" -name 'm1.*' -type f -exec basename {} \; | sort)
-    expected=49
+    expected=50
     actual=$(echo "${all}" | wc -l | xargs)
     if [ ! "${actual}" = "${expected}" ]; then
         echo "Exactly ${expected} metrics were expected, but ${actual} were actually collected"