Provide a New Java Rule checking if System.out and System.err is not …

…used Closes gh-20
enofex · Jun 12, 2024 · 22eb2af · 22eb2af
1 parent 2355d20
commit 22eb2af
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diff --git a/docs/USERGUIDE.md b/docs/USERGUIDE.md
@@ -145,6 +145,17 @@ Taikai.builder()
     .check();
 ```
 
+- **No Usage of System.out or System.err**: Enforce disallowing the use of System.out and System.err for logging, encouraging the use of proper logging frameworks instead.
+
+```java
+Taikai.builder()
+    .namespace("com.company.yourproject")
+    .java(java -> java
+        .noUsageOfSystemOutOrErr())
+    .build()
+    .check();
+```
+
 ## Spring Configuration
 
 Spring configuration involves defining constraints specific to Spring Framework usage.

diff --git a/src/main/java/com/enofex/taikai/java/JavaConfigurer.java b/src/main/java/com/enofex/taikai/java/JavaConfigurer.java
@@ -3,6 +3,7 @@
 import static com.enofex.taikai.java.Deprecations.notUseDeprecatedAPIs;
 import static com.enofex.taikai.java.FieldsShouldNotBePublic.notBePublic;
 import static com.enofex.taikai.java.HashCodeAndEquals.implementHashCodeAndEquals;
+import static com.enofex.taikai.java.NoSystemOutOrErr.notUseSystemOutOrErr;
 import static com.enofex.taikai.java.UtilityClasses.beFinal;
 import static com.enofex.taikai.java.UtilityClasses.havePrivateConstructor;
 import static com.enofex.taikai.java.UtilityClasses.utilityClasses;
@@ -95,6 +96,14 @@ public JavaConfigurer noUsageOf(Class clazz, Configuration configuration) {
         configuration));
   }
 
+  public JavaConfigurer noUsageOfSystemOutOrErr() {
+    return noUsageOfSystemOutOrErr(null);
+  }
+
+  public JavaConfigurer noUsageOfSystemOutOrErr(Configuration configuration) {
+    return addRule(TaikaiRule.of(classes().should(notUseSystemOutOrErr()), configuration));
+  }
+
   @Override
   public void disable() {
     disable(ImportsConfigurer.class);

diff --git a/src/main/java/com/enofex/taikai/java/NoSystemOutOrErr.java b/src/main/java/com/enofex/taikai/java/NoSystemOutOrErr.java
@@ -0,0 +1,34 @@
+package com.enofex.taikai.java;
+
+import com.tngtech.archunit.core.domain.JavaClass;
+import com.tngtech.archunit.lang.ArchCondition;
+import com.tngtech.archunit.lang.ConditionEvents;
+import com.tngtech.archunit.lang.SimpleConditionEvent;
+
+final class NoSystemOutOrErr {
+
+  private NoSystemOutOrErr() {
+  }
+
+  static ArchCondition<JavaClass> notUseSystemOutOrErr() {
+    return new ArchCondition<>("not call System.out or System.err") {
+      @Override
+      public void check(JavaClass javaClass, ConditionEvents events) {
+        javaClass.getFieldAccessesFromSelf().stream()
+            .filter(fieldAccess -> fieldAccess.getTargetOwner().isEquivalentTo(System.class))
+            .forEach(fieldAccess -> {
+              String fieldName = fieldAccess.getTarget().getName();
+
+              if ("out".equals(fieldName) || "err".equals(fieldName)) {
+                String message = String.format("Method %s calls %s.%s",
+                    fieldAccess.getOrigin().getFullName(),
+                    fieldAccess.getTargetOwner().getName(),
+                    fieldAccess.getTarget().getName());
+
+                events.add(SimpleConditionEvent.violated(fieldAccess, message));
+              }
+            });
+      }
+    };
+  }
+}
diff --git a/src/test/java/com/enofex/taikai/ArchitectureTest.java b/src/test/java/com/enofex/taikai/ArchitectureTest.java
@@ -1,6 +1,5 @@
 package com.enofex.taikai;
 
-import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 import org.junit.jupiter.api.Test;
@@ -21,6 +20,7 @@ void shouldFulfilConstrains() {
             .methodsShouldNotThrowGenericException()
             .utilityClassesShouldBeFinalAndHavePrivateConstructor()
             .fieldsShouldNotBePublic()
+            .noUsageOfSystemOutOrErr()
             .noUsageOf(Date.class)
             .noUsageOf(Calendar.class)
             .noUsageOf("java.text.SimpleDateFormat")

diff --git a/src/test/java/com/enofex/taikai/Usage.java b/src/test/java/com/enofex/taikai/Usage.java
@@ -1,6 +1,5 @@
 package com.enofex.taikai;
 
-import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 
@@ -35,6 +34,7 @@ public static void main(String[] args) {
                 .classesShouldNotBeAnnotatedWithDisabled()
                 .methodsShouldNotBeAnnotatedWithDisabled()))
         .java(java -> java
+            .noUsageOfSystemOutOrErr()
             .noUsageOfDeprecatedAPIs()
             .classesShouldImplementHashCodeAndEquals()
             .methodsShouldNotThrowGenericException()