fix: Improve EC69

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- [#21](https://github.com/green-code-initiative/ecoCode-java/issues/21) Improvement: some method calls are legitimate in a for loop expression.
 - [#49](https://github.com/green-code-initiative/ecoCode-java/pull/49) Add test to ensure all Rules are registered
 - [#336](https://github.com/green-code-initiative/ecoCode/issues/336) [Adds Maven Wrapper](https://github.com/green-code-initiative/ecoCode-java/pull/67)
 

src/main/java/fr/greencodeinitiative/java/checks/NoFunctionCallWhenDeclaringForLoop.java

@@ -59,22 +59,28 @@ public void visitNode(Tree tree) {
             method.condition().accept(invocationMethodVisitor);
         }
         // update
-        // initaliser
         method.update().accept(invocationMethodVisitor);
-        method.initializer().accept(invocationMethodVisitor);
     }
 
     private class MethodInvocationInForStatementVisitor extends BaseTreeVisitor {
 
         @Override
         public void visitMethodInvocation(MethodInvocationTree tree) {
-            if (!lineAlreadyHasThisIssue(tree)) {
+            if (!lineAlreadyHasThisIssue(tree) && !isIteratorMethod(tree)) {
                 report(tree);
                 return;
             }
             super.visitMethodInvocation(tree);
         }
 
+        private boolean isIteratorMethod(MethodInvocationTree tree) {
+            boolean isIterator = tree.methodSymbol().owner().type().isSubtypeOf("java.util.Iterator");
+            String methodName = tree.methodSelect().lastToken().text();
+            boolean isMethodNext = methodName.equals("next");
+            boolean isMethodHasNext = methodName.equals("hasNext");
+            return isIterator && (isMethodNext || isMethodHasNext);
+        }
+
         private boolean lineAlreadyHasThisIssue(Tree tree) {
             if (tree.firstToken() != null) {
                 final String classname = getFullyQualifiedNameOfClassOf(tree);

src/test/files/NoFunctionCallWhenDeclaringForLoop.java

@@ -15,6 +15,10 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Arrays;
 class NoFunctionCallWhenDeclaringForLoop {
     NoFunctionCallWhenDeclaringForLoop(NoFunctionCallWhenDeclaringForLoop mc) {
     }
@@ -30,7 +34,7 @@ public int incrementeMyValue(int i) {
     public void test1() {
         for (int i = 0; i < 20; i++) {
             System.out.println(i);
-            boolean b = getMyValue() > 6;
+            boolean b = this.getMyValue() > 6;
         }
     }
 
@@ -42,8 +46,9 @@ public void test2() {
 
     }
 
+    // compliant, the function is called only once in the initialization so it's not a performance issue
     public void test3() {
-        for (int i = getMyValue(); i < 20; i++) {  // Noncompliant {{Do not call a function when declaring a for-type loop}}
+        for (int i = getMyValue(); i < 20; i++) {
             System.out.println(i);
             boolean b = getMyValue() > 6;
         }
@@ -70,4 +75,42 @@ public void test6() {
         }
     }
 
+    // compliant, iterators are allowed to be called in a for loop
+    public void test7() {
+        List<String> joursSemaine = Arrays.asList("Lundi", "Mardi", "Mercredi", "Jeudi", "Vendredi", "Samedi", "Dimanche");
+
+        String jour;
+        // iterator is allowed
+        for (Iterator<String> iterator = joursSemaine.iterator(); iterator.hasNext(); jour = iterator.next()) {
+            System.out.println(jour);
+        }
+
+        // subclass of iterator is allowed
+        for (ListIterator<String> iterator = joursSemaine.listIterator(); iterator.hasNext(); jour = iterator.next()) {
+            System.out.println(jour);
+        }
+
+        // iterator called in an indirect way is allowed
+        for (OtherClassWithIterator otherClass = new OtherClassWithIterator(joursSemaine); otherClass.iterator.hasNext(); jour = otherClass.iterator.next()) {
+            System.out.println(jour);
+        }
+        // but using a method that returns an iterator causes an issue
+        for (OtherClassWithIterator otherClass = new OtherClassWithIterator(joursSemaine); otherClass.getIterator().hasNext(); jour = otherClass.getIterator().next()) {  // Noncompliant {{Do not call a function when declaring a for-type loop}}
+            System.out.println(jour);
+        }
+
+    }
+
+}
+
+class OtherClassWithIterator {
+    public Iterator<String> iterator;
+
+    public OtherClassWithIterator(Iterator<String> iterator){
+        this.iterator = iterator;
+    }
+
+    public Iterator getIterator(){
+        return iterator;
+    }
 }