Refactor ReadKotlinClassHeaderAnnotationVisitor

Extract a hierarchy of four nested classes instead of anonymous

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/header/ReadKotlinClassHeaderAnnotationVisitor.java

@@ -96,11 +96,11 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
 
             switch (newKind) {
                 case CLASS:
-                    return kotlinClassOrPackageVisitor(annotation);
+                    return new ClassHeaderReader();
                 case PACKAGE_FACADE:
-                    return kotlinClassOrPackageVisitor(annotation);
+                    return new PackageHeaderReader();
                 case SYNTHETIC_CLASS:
-                    return syntheticClassAnnotationVisitor();
+                    return new SyntheticClassHeaderReader();
                 default:
                     throw new IllegalStateException("Unknown kind: " + newKind);
             }
@@ -118,17 +118,26 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
     public void visitEnd() {
     }
 
-    @NotNull
+    private abstract class HeaderAnnotationArgumentVisitor implements AnnotationArgumentVisitor {
-    private AnnotationArgumentVisitor kotlinClassOrPackageVisitor(@NotNull final JvmClassName annotationClassName) {
+        protected final JvmClassName annotationClassName;
-        return new AnnotationArgumentVisitor() {
+
+        public HeaderAnnotationArgumentVisitor(@NotNull JvmClassName annotationClassName) {
+            this.annotationClassName = annotationClassName;
+        }
+
         @Override
         public void visit(@Nullable Name name, @Nullable Object value) {
-                visitIntValueForSupportedAnnotation(name, value, annotationClassName);
+            if (name != null && name.asString().equals(ABI_VERSION_FIELD_NAME)) {
+                version = value == null ? AbiVersionUtil.INVALID_VERSION : (Integer) value;
+            }
+            else {
+                unexpectedArgument(name);
+            }
         }
 
         @Override
         public void visitEnum(@NotNull Name name, @NotNull ClassId enumClassId, @NotNull Name enumEntryName) {
-                unexpectedArgument(name, annotationClassName);
+            unexpectedEnumArgument(name, enumClassId, enumEntryName);
         }
 
         @Override
@@ -159,7 +168,7 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
 
                 @Override
                 public void visitEnum(@NotNull ClassId enumClassId, @NotNull Name enumEntryName) {
-                        unexpectedArgument(null, annotationClassName);
+                    unexpectedArgument(null);
                 }
 
                 @Override
@@ -170,18 +179,41 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
             };
         }
 
+        @Nullable
+        protected AnnotationArrayArgumentVisitor unexpectedArgument(@Nullable Name name) {
+            if (isAbiVersionCompatible(version)) {
+                throw new IllegalStateException("Unexpected argument " + name + " for annotation " + annotationClassName);
+            }
+            return null;
+        }
+
+        protected void unexpectedEnumArgument(@NotNull Name name, @NotNull ClassId enumClassId, @NotNull Name enumEntryName) {
+            if (isAbiVersionCompatible(version)) {
+                throw new IllegalStateException("Unexpected enum entry for class annotation " + annotationClassName + ": " +
+                                                name + "=" + enumClassId + "." + enumEntryName);
+            }
+        }
+
         @Override
         public void visitEnd() {
         }
-        };
     }
 
-    @NotNull
+    private class ClassHeaderReader extends HeaderAnnotationArgumentVisitor {
-    private AnnotationArgumentVisitor syntheticClassAnnotationVisitor() {
+        public ClassHeaderReader() {
-        return new AnnotationArgumentVisitor() {
+            super(KotlinClass.CLASS_NAME);
-            @Override
+        }
-            public void visit(@Nullable Name name, @Nullable Object value) {
+    }
-                visitIntValueForSupportedAnnotation(name, value, KotlinSyntheticClass.CLASS_NAME);
+
+    private class PackageHeaderReader extends HeaderAnnotationArgumentVisitor {
+        public PackageHeaderReader() {
+            super(JvmClassName.byFqNameWithoutInnerClasses(KOTLIN_PACKAGE));
+        }
+    }
+
+    private class SyntheticClassHeaderReader extends HeaderAnnotationArgumentVisitor {
+        public SyntheticClassHeaderReader() {
+            super(KotlinSyntheticClass.CLASS_NAME);
         }
 
         @Override
@@ -190,41 +222,10 @@ public class ReadKotlinClassHeaderAnnotationVisitor implements AnnotationVisitor
                 syntheticClassKind = valueOfOrNull(KotlinSyntheticClass.Kind.class, enumEntryName.asString());
                 if (syntheticClassKind != null) return;
             }
-                if (isAbiVersionCompatible(version)) {
+            unexpectedEnumArgument(name, enumClassId, enumEntryName);
-                    throw new IllegalStateException("Unexpected enum entry for synthetic class annotation: " +
-                                                    name + "=" + enumClassId + "." + enumEntryName);
         }
     }
 
-            @Nullable
-            @Override
-            public AnnotationArrayArgumentVisitor visitArray(@NotNull Name name) {
-                return unexpectedArgument(name, KotlinSyntheticClass.CLASS_NAME);
-            }
-
-            @Override
-            public void visitEnd() {
-            }
-        };
-    }
-
-    private void visitIntValueForSupportedAnnotation(@Nullable Name name, @Nullable Object value, @NotNull JvmClassName className) {
-        if (name != null && name.asString().equals(ABI_VERSION_FIELD_NAME)) {
-            version = value == null ? AbiVersionUtil.INVALID_VERSION : (Integer) value;
-        }
-        else {
-            unexpectedArgument(name, className);
-        }
-    }
-
-    @Nullable
-    private AnnotationArrayArgumentVisitor unexpectedArgument(@Nullable Name name, @NotNull JvmClassName annotationClassName) {
-        if (isAbiVersionCompatible(version)) {
-            throw new IllegalStateException("Unexpected argument " + name + " for annotation " + annotationClassName);
-        }
-        return null;
-    }
-
     // This function is needed here because Enum.valueOf() throws exception if there's no such value,
     // but we don't want to fail if we're loading the header with an _incompatible_ ABI version
     @Nullable