From fcbf07b798d15bd6c5849bc03eb2ef0bffc539d3 Mon Sep 17 00:00:00 2001
From: Leonard Husmann <leonard.husmann@tum.de>
Date: Fri, 28 Apr 2023 10:43:06 +0200
Subject: [PATCH] add support to detect references of fields in methods

This adds a method to the public API of FieldsShould.java to check if a field has been accessed by methods matching a given predicate.

Issue: #857
Signed-off-by: Leonard Husmann <leonard.husmann@tum.de>
---
 .../archunit/lang/conditions/ArchConditions.java     | 12 ++++++++++++
 .../archunit/lang/syntax/FieldsShouldInternal.java   |  6 ++++++
 .../archunit/lang/syntax/elements/FieldsShould.java  | 10 ++++++++++
 3 files changed, 28 insertions(+)

diff --git a/archunit/src/main/java/com/tngtech/archunit/lang/conditions/ArchConditions.java b/archunit/src/main/java/com/tngtech/archunit/lang/conditions/ArchConditions.java
index d59fe58788..060b3a97e1 100644
--- a/archunit/src/main/java/com/tngtech/archunit/lang/conditions/ArchConditions.java
+++ b/archunit/src/main/java/com/tngtech/archunit/lang/conditions/ArchConditions.java
@@ -1274,6 +1274,18 @@ public static ArchCondition<JavaCodeUnit> onlyBeCalledByConstructorsThat(Describ
                 origin.is(matching(JavaConstructor.class, predicate)), GET_CALLS_OF_SELF);
     }
 
+    @PublicAPI(usage = ACCESS)
+    public static ArchCondition<JavaField> notBeAccessedByMethodsThat(DescribedPredicate<? super JavaMethod> predicate) {
+        return new ArchCondition<JavaField>("not be accessed by methods that " + predicate.getDescription()) {
+            @Override
+            public void check(JavaField field, ConditionEvents events) {
+                field.getAccessesToSelf().stream()
+                        .filter(access -> access.getOrigin() instanceof JavaMethod && predicate.test((JavaMethod) access.getOrigin()))
+                        .forEach(violation -> events.add(SimpleConditionEvent.violated(field, violation.getDescription())));
+            }
+        };
+    }
+
     /**
      * Derives an {@link ArchCondition} from a {@link DescribedPredicate}. Similar to {@link ArchCondition#from(DescribedPredicate)},
      * but more conveniently creates a message to be used within a 'have'-sentence.
diff --git a/archunit/src/main/java/com/tngtech/archunit/lang/syntax/FieldsShouldInternal.java b/archunit/src/main/java/com/tngtech/archunit/lang/syntax/FieldsShouldInternal.java
index 4cddb9baf0..aa2448d722 100644
--- a/archunit/src/main/java/com/tngtech/archunit/lang/syntax/FieldsShouldInternal.java
+++ b/archunit/src/main/java/com/tngtech/archunit/lang/syntax/FieldsShouldInternal.java
@@ -20,6 +20,7 @@
 import com.tngtech.archunit.base.DescribedPredicate;
 import com.tngtech.archunit.core.domain.JavaClass;
 import com.tngtech.archunit.core.domain.JavaField;
+import com.tngtech.archunit.core.domain.JavaMethod;
 import com.tngtech.archunit.lang.ArchCondition;
 import com.tngtech.archunit.lang.ClassesTransformer;
 import com.tngtech.archunit.lang.Priority;
@@ -93,4 +94,9 @@ public FieldsShouldInternal haveRawType(DescribedPredicate<? super JavaClass> pr
     public FieldsShouldInternal notHaveRawType(DescribedPredicate<? super JavaClass> predicate) {
         return addCondition(not(ArchConditions.haveRawType(predicate)));
     }
+
+    @Override
+    public FieldsShouldInternal notBeAccessedByMethodsThat(DescribedPredicate<? super JavaMethod> predicate) {
+        return addCondition(ArchConditions.notBeAccessedByMethodsThat(predicate));
+    }
 }
diff --git a/archunit/src/main/java/com/tngtech/archunit/lang/syntax/elements/FieldsShould.java b/archunit/src/main/java/com/tngtech/archunit/lang/syntax/elements/FieldsShould.java
index dc8b39260e..4e7118db1e 100644
--- a/archunit/src/main/java/com/tngtech/archunit/lang/syntax/elements/FieldsShould.java
+++ b/archunit/src/main/java/com/tngtech/archunit/lang/syntax/elements/FieldsShould.java
@@ -18,6 +18,7 @@
 import com.tngtech.archunit.PublicAPI;
 import com.tngtech.archunit.base.DescribedPredicate;
 import com.tngtech.archunit.core.domain.JavaClass;
+import com.tngtech.archunit.core.domain.JavaMethod;
 import com.tngtech.archunit.core.domain.properties.HasName;
 import com.tngtech.archunit.lang.syntax.ArchRuleDefinition;
 
@@ -156,6 +157,15 @@ public interface FieldsShould<CONJUNCTION extends FieldsShouldConjunction> exten
     @PublicAPI(usage = ACCESS)
     CONJUNCTION notHaveRawType(DescribedPredicate<? super JavaClass> predicate);
 
+    /**
+     * Asserts that fields are not accessed by methods matching the given predicate.
+     *
+     * @param predicate A predicate determining the methods this field should not be accessed by
+     * @return A syntax element that can either be used as working rule, or to continue specifying a more complex rule
+     */
+    @PublicAPI(usage = ACCESS)
+    CONJUNCTION notBeAccessedByMethodsThat(DescribedPredicate<? super JavaMethod> predicate);
+
     /**
      * Asserts that fields are static.
      *