Code optimization

dubbo-common/src/main/java/org/apache/dubbo/common/URL.java

@@ -116,7 +116,7 @@ class URL implements Serializable {
 
     private static final long serialVersionUID = -1985165475234910535L;
 
-    private static Map<String, URL> cachedURLs = new LRUCache<>();
+    private static final Map<String, URL> cachedURLs = new LRUCache<>();
 
     private final URLAddress urlAddress;
     private final URLParam urlParam;

dubbo-common/src/main/java/org/apache/dubbo/common/URLBuilder.java

@@ -43,9 +43,9 @@ public final class URLBuilder extends ServiceConfigURL {
 
     private String path;
 
-    private Map<String, String> parameters;
+    private final Map<String, String> parameters;
 
-    private Map<String, Object> attributes;
+    private final Map<String, Object> attributes;
 
     private Map<String, Map<String, String>> methodParameters;
 

dubbo-common/src/main/java/org/apache/dubbo/common/beans/factory/ScopeBeanFactory.java

@@ -47,12 +47,12 @@ public class ScopeBeanFactory {
     protected static final ErrorTypeAwareLogger LOGGER = LoggerFactory.getErrorTypeAwareLogger(ScopeBeanFactory.class);
 
     private final ScopeBeanFactory parent;
-    private ExtensionAccessor extensionAccessor;
-    private List<ExtensionPostProcessor> extensionPostProcessors;
-    private ConcurrentHashMap<Class, AtomicInteger> beanNameIdCounterMap = new ConcurrentHashMap<>();
-    private List<BeanInfo> registeredBeanInfos = new CopyOnWriteArrayList<>();
+    private final ExtensionAccessor extensionAccessor;
+    private final List<ExtensionPostProcessor> extensionPostProcessors;
+    private final ConcurrentHashMap<Class<?>, AtomicInteger> beanNameIdCounterMap = new ConcurrentHashMap<>();
+    private final List<BeanInfo> registeredBeanInfos = new CopyOnWriteArrayList<>();
     private InstantiationStrategy instantiationStrategy;
-    private AtomicBoolean destroyed = new AtomicBoolean();
+    private final AtomicBoolean destroyed = new AtomicBoolean();
 
     public ScopeBeanFactory(ScopeBeanFactory parent, ExtensionAccessor extensionAccessor) {
         this.parent = parent;
@@ -207,6 +207,7 @@ public <T> T getBean(String name, Class<T> type) {
         return bean;
     }
 
+    @SuppressWarnings("unchecked")
     private <T> T getBeanInternal(String name, Class<T> type) {
         checkDestroyed();
         // All classes are derived from java.lang.Object, cannot filter bean by it
@@ -272,8 +273,8 @@ private void checkDestroyed() {
     }
 
     static class BeanInfo {
-        private String name;
-        private Object instance;
+        private final String name;
+        private final Object instance;
 
         public BeanInfo(String name, Object instance) {
             this.name = name;

dubbo-common/src/main/java/org/apache/dubbo/common/beanutil/JavaBeanDescriptor.java

@@ -57,7 +57,7 @@ public final class JavaBeanDescriptor implements Serializable, Iterable<Map.Entr
     private String className;
     private int type;
 
-    private Map<Object, Object> properties = new LinkedHashMap<>();
+    private final Map<Object, Object> properties = new LinkedHashMap<>();
 
     public JavaBeanDescriptor() {}
 

dubbo-common/src/main/java/org/apache/dubbo/common/bytecode/Mixin.java

@@ -30,7 +30,7 @@
  */
 public abstract class Mixin {
     private static final String PACKAGE_NAME = Mixin.class.getPackage().getName();
-    private static AtomicLong MIXIN_CLASS_COUNTER = new AtomicLong(0);
+    private static final AtomicLong MIXIN_CLASS_COUNTER = new AtomicLong(0);
 
     protected Mixin() {
     }

dubbo-common/src/main/java/org/apache/dubbo/common/cache/FileCacheStore.java

@@ -49,10 +49,10 @@
 public class FileCacheStore {
     private static final ErrorTypeAwareLogger logger = LoggerFactory.getErrorTypeAwareLogger(FileCacheStore.class);
 
-    private String cacheFilePath;
-    private File cacheFile;
-    private File lockFile;
-    private FileLock directoryLock;
+    private final String cacheFilePath;
+    private final File cacheFile;
+    private final File lockFile;
+    private final FileLock directoryLock;
 
     private FileCacheStore(String cacheFilePath, File cacheFile, File lockFile, FileLock directoryLock) {
         this.cacheFilePath = cacheFilePath;

dubbo-common/src/main/java/org/apache/dubbo/common/config/Environment.java

@@ -70,8 +70,8 @@ public class Environment extends LifecycleAdapter implements ApplicationExt {
 
     private String localMigrationRule;
 
-    private AtomicBoolean initialized = new AtomicBoolean(false);
-    private ScopeModel scopeModel;
+    private final AtomicBoolean initialized = new AtomicBoolean(false);
+    private final ScopeModel scopeModel;
 
     public Environment(ScopeModel scopeModel) {
         this.scopeModel = scopeModel;

dubbo-common/src/main/java/org/apache/dubbo/common/config/ModuleEnvironment.java

@@ -39,11 +39,11 @@ public class ModuleEnvironment extends Environment implements ModuleExt {
 
     public static final String NAME = "moduleEnvironment";
 
-    private AtomicBoolean initialized = new AtomicBoolean(false);
+    private final AtomicBoolean initialized = new AtomicBoolean(false);
 
     private final ModuleModel moduleModel;
 
-    private Environment applicationDelegate;
+    private final Environment applicationDelegate;
 
     private OrderedPropertiesConfiguration orderedPropertiesConfiguration;
 

dubbo-common/src/main/java/org/apache/dubbo/common/config/OrderedPropertiesConfiguration.java

@@ -28,7 +28,7 @@
 
 public class OrderedPropertiesConfiguration implements Configuration {
     private Properties properties;
-    private ModuleModel moduleModel;
+    private final ModuleModel moduleModel;
 
     public OrderedPropertiesConfiguration(ModuleModel moduleModel) {
         this.moduleModel = moduleModel;

dubbo-common/src/main/java/org/apache/dubbo/common/config/PrefixedConfiguration.java

@@ -20,9 +20,9 @@
 
 public class PrefixedConfiguration implements Configuration {
 
-    private String prefix;
+    private final String prefix;
 
-    private Configuration origin;
+    private final Configuration origin;
 
     public PrefixedConfiguration(Configuration origin, String prefix) {
         this.origin = origin;

dubbo-common/src/main/java/org/apache/dubbo/common/config/configcenter/wrapper/CompositeDynamicConfiguration.java

@@ -37,7 +37,7 @@ public class CompositeDynamicConfiguration implements DynamicConfiguration {
 
     private static final ErrorTypeAwareLogger logger = LoggerFactory.getErrorTypeAwareLogger(CompositeDynamicConfiguration.class);
 
-    private Set<DynamicConfiguration> configurations = new HashSet<>();
+    private final Set<DynamicConfiguration> configurations = new HashSet<>();
 
     public void addConfiguration(DynamicConfiguration configuration) {
         if (configuration != null) {

dubbo-common/src/main/java/org/apache/dubbo/common/extension/AdaptiveClassCodeGenerator.java

@@ -74,7 +74,7 @@ public class AdaptiveClassCodeGenerator {
 
     private final Class<?> type;
 
-    private String defaultExtName;
+    private final String defaultExtName;
 
     public AdaptiveClassCodeGenerator(Class<?> type, String defaultExtName) {
         this.type = type;

dubbo-common/src/main/java/org/apache/dubbo/common/extension/ExtensionLoader.java

@@ -134,27 +134,27 @@ public class ExtensionLoader<T> {
 
     private Set<Class<?>> cachedWrapperClasses;
 
-    private Map<String, IllegalStateException> exceptions = new ConcurrentHashMap<>();
+    private final Map<String, IllegalStateException> exceptions = new ConcurrentHashMap<>();
 
     private static volatile LoadingStrategy[] strategies = loadLoadingStrategies();
 
-    private static Map<String, String> specialSPILoadingStrategyMap = getSpecialSPILoadingStrategyMap();
+    private static final Map<String, String> specialSPILoadingStrategyMap = getSpecialSPILoadingStrategyMap();
 
     private static SoftReference<Map<java.net.URL, List<String>>> urlListMapCache = new SoftReference<>(
         new ConcurrentHashMap<>());
 
-    private static List<String> ignoredInjectMethodsDesc = getIgnoredInjectMethodsDesc();
+    private static final List<String> ignoredInjectMethodsDesc = getIgnoredInjectMethodsDesc();
 
     /**
      * Record all unacceptable exceptions when using SPI
      */
-    private Set<String>                  unacceptableExceptions = new ConcurrentHashSet<>();
-    private ExtensionDirector            extensionDirector;
-    private List<ExtensionPostProcessor> extensionPostProcessors;
+    private final Set<String>                  unacceptableExceptions = new ConcurrentHashSet<>();
+    private final ExtensionDirector            extensionDirector;
+    private final List<ExtensionPostProcessor> extensionPostProcessors;
     private InstantiationStrategy        instantiationStrategy;
-    private ActivateComparator           activateComparator;
-    private ScopeModel                   scopeModel;
-    private AtomicBoolean                destroyed              = new AtomicBoolean();
+    private final ActivateComparator           activateComparator;
+    private final ScopeModel                   scopeModel;
+    private final AtomicBoolean                destroyed              = new AtomicBoolean();
 
     public static void setLoadingStrategies(LoadingStrategy... strategies) {
         if (ArrayUtils.isNotEmpty(strategies)) {

dubbo-common/src/main/java/org/apache/dubbo/common/function/Predicates.java

@@ -57,7 +57,7 @@ static <T> Predicate<T> alwaysFalse() {
      * @return non-null
      */
     static <T> Predicate<T> and(Predicate<T>... predicates) {
-        return of(predicates).reduce((a, b) -> a.and(b)).orElseGet(Predicates::alwaysTrue);
+        return of(predicates).reduce(Predicate::and).orElseGet(Predicates::alwaysTrue);
     }
 
     /**
@@ -68,7 +68,7 @@ static <T> Predicate<T> and(Predicate<T>... predicates) {
      * @return non-null
      */
     static <T> Predicate<T> or(Predicate<T>... predicates) {
-        return of(predicates).reduce((a, b) -> a.or(b)).orElse(e -> true);
+        return of(predicates).reduce(Predicate::or).orElse(e -> true);
     }
 
 }

dubbo-common/src/main/java/org/apache/dubbo/common/function/Streams.java

@@ -47,6 +47,7 @@ static <T, S extends Iterable<T>> Set<T> filterSet(S values, Predicate<T> predic
         return filterStream(values, predicate).collect(LinkedHashSet::new, Set::add, Set::addAll);
     }
 
+    @SuppressWarnings("unchecked")
     static <T, S extends Iterable<T>> S filter(S values, Predicate<T> predicate) {
         final boolean isSet = Set.class.isAssignableFrom(values.getClass());
         return (S) (isSet ? filterSet(values, predicate) : filterList(values, predicate));

dubbo-common/src/main/java/org/apache/dubbo/common/function/ThrowableConsumer.java

@@ -58,7 +58,6 @@ default void execute(T t) throws RuntimeException {
      * @param t        the function argument
      * @param consumer {@link ThrowableConsumer}
      * @param <T>      the source type
-     * @return the result after execution
      */
     static <T> void execute(T t, ThrowableConsumer<T> consumer) {
         consumer.execute(t);

dubbo-common/src/main/java/org/apache/dubbo/common/io/Bytes.java

@@ -41,9 +41,9 @@ public class Bytes {
 
     private static final int MASK4 = 0x0f, MASK6 = 0x3f, MASK8 = 0xff;
 
-    private static final Map<Integer, byte[]> DECODE_TABLE_MAP = new ConcurrentHashMap<Integer, byte[]>();
+    private static final Map<Integer, byte[]> DECODE_TABLE_MAP = new ConcurrentHashMap<>();
 
-    private static ThreadLocal<MessageDigest> MD = new ThreadLocal<MessageDigest>();
+    private static final ThreadLocal<MessageDigest> MD = new ThreadLocal<>();
 
     private Bytes() {
     }

dubbo-common/src/main/java/org/apache/dubbo/common/lang/ShutdownHookCallbacks.java

@@ -36,7 +36,7 @@ public class ShutdownHookCallbacks implements Disposable {
 
     private final List<ShutdownHookCallback> callbacks = new LinkedList<>();
 
-    private ApplicationModel applicationModel;
+    private final ApplicationModel applicationModel;
 
     public ShutdownHookCallbacks(ApplicationModel applicationModel) {
         this.applicationModel = applicationModel;
@@ -45,7 +45,9 @@ public ShutdownHookCallbacks(ApplicationModel applicationModel) {
 
     public ShutdownHookCallbacks addCallback(ShutdownHookCallback callback) {
         synchronized (this) {
-            this.callbacks.add(callback);
+            if (!callbacks.contains(callback)) {
+                this.callbacks.add(callback);
+            }
         }
         return this;
     }
@@ -65,7 +67,7 @@ public void destroy() {
 
     private void loadCallbacks() {
         ExtensionLoader<ShutdownHookCallback> loader =
-                applicationModel.getExtensionLoader(ShutdownHookCallback.class);
+            applicationModel.getExtensionLoader(ShutdownHookCallback.class);
         loader.getSupportedExtensionInstances().forEach(this::addCallback);
     }
 

dubbo-common/src/main/java/org/apache/dubbo/common/store/support/SimpleDataStore.java

@@ -28,17 +28,17 @@
 public class SimpleDataStore implements DataStore {
 
     // <component name or id, <data-name, data-value>>
-    private ConcurrentMap<String, ConcurrentMap<String, Object>> data =
-        new ConcurrentHashMap<String, ConcurrentMap<String, Object>>();
+    private final ConcurrentMap<String, ConcurrentMap<String, Object>> data =
+        new ConcurrentHashMap<>();
 
     @Override
     public Map<String, Object> get(String componentName) {
         ConcurrentMap<String, Object> value = data.get(componentName);
         if (value == null) {
-            return new HashMap<String, Object>();
+            return new HashMap<>();
         }
 
-        return new HashMap<String, Object>(value);
+        return new HashMap<>(value);
     }
 
     @Override

dubbo-common/src/main/java/org/apache/dubbo/common/threadpool/ThreadlessExecutor.java

@@ -172,7 +172,7 @@ public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedE
     }
 
     private static class RunnableWrapper implements Runnable {
-        private Runnable runnable;
+        private final Runnable runnable;
 
         public RunnableWrapper(Runnable runnable) {
             this.runnable = runnable;

dubbo-common/src/main/java/org/apache/dubbo/common/threadpool/manager/Ring.java

@@ -25,7 +25,7 @@ public class Ring<T> {
 
     AtomicInteger count = new AtomicInteger();
 
-    private List<T> itemList = new CopyOnWriteArrayList<T>();
+    private final List<T> itemList = new CopyOnWriteArrayList<>();
 
     public void addItem(T t) {
         if (t != null) {

dubbo-common/src/main/java/org/apache/dubbo/common/utils/AnnotationUtils.java

@@ -61,6 +61,7 @@ public interface AnnotationUtils {
      * @param <A>                 the type of annotation
      * @return If resolved, return the type of annotation, or <code>null</code>
      */
+    @SuppressWarnings("unchecked")
     static <A extends Annotation> Class<A> resolveAnnotationType(AnnotatedElement annotatedElement,
                                                                  String annotationClassName) {
         ClassLoader classLoader = annotatedElement.getClass().getClassLoader();
@@ -192,6 +193,7 @@ static List<Annotation> getAllDeclaredAnnotations(AnnotatedElement annotatedElem
      * @param annotationsToFilter the annotations to filter
      * @return non-null read-only {@link List}
      */
+    @SuppressWarnings("unchecked")
     static List<Annotation> getAllDeclaredAnnotations(Class<?> type, Predicate<Annotation>... annotationsToFilter) {
 
         if (type == null) {
@@ -223,6 +225,7 @@ static List<Annotation> getAllDeclaredAnnotations(Class<?> type, Predicate<Annot
      * @param metaAnnotationsToFilter the meta annotations to filter
      * @return non-null read-only {@link List}
      */
+    @SuppressWarnings("unchecked")
     static List<Annotation> getMetaAnnotations(Class<? extends Annotation> annotationType,
                                                Predicate<Annotation>... metaAnnotationsToFilter) {
         return getDeclaredAnnotations(annotationType,
@@ -243,6 +246,7 @@ static List<Annotation> getMetaAnnotations(Class<? extends Annotation> annotatio
      * @param annotationsToFilter the annotations to filter
      * @return non-null read-only {@link List}
      */
+    @SuppressWarnings("unchecked")
     static List<Annotation> getAllMetaAnnotations(Class<? extends Annotation> annotationType,
                                                   Predicate<Annotation>... annotationsToFilter) {
 
@@ -280,6 +284,7 @@ static <A extends Annotation> A findAnnotation(AnnotatedElement annotatedElement
      * @param <A>              the required type of annotation
      * @return If found, return first matched-type {@link Annotation annotation}, or <code>null</code>
      */
+    @SuppressWarnings("unchecked")
     static <A extends Annotation> A findAnnotation(AnnotatedElement annotatedElement, Class<A> annotationType) {
         return (A) filterFirst(getAllDeclaredAnnotations(annotatedElement), a -> isSameType(a, annotationType));
     }
@@ -292,6 +297,7 @@ static <A extends Annotation> A findAnnotation(AnnotatedElement annotatedElement
      * @param <A>                the type of required annotation
      * @return if found, return all matched results, or get an {@link Collections#emptyList() empty list}
      */
+    @SuppressWarnings("unchecked")
     static <A extends Annotation> List<A> findMetaAnnotations(Class<? extends Annotation> annotationType,
                                                               Class<A> metaAnnotationType) {
         return (List<A>) getAllMetaAnnotations(annotationType, a -> isSameType(a, metaAnnotationType));
@@ -305,6 +311,7 @@ static <A extends Annotation> List<A> findMetaAnnotations(Class<? extends Annota
      * @param <A>                the type of required annotation
      * @return if found, return all matched results, or get an {@link Collections#emptyList() empty list}
      */
+    @SuppressWarnings("unchecked")
     static <A extends Annotation> List<A> findMetaAnnotations(AnnotatedElement annotatedElement,
                                                               Class<A> metaAnnotationType) {
         List<A> metaAnnotations = new LinkedList<>();
@@ -395,6 +402,7 @@ static boolean isAnnotationPresent(Class<?> type,
      * @param annotationType the class of annotation
      * @return If the specified annotation type is present, return <code>true</code>, or <code>false</code>
      */
+    @SuppressWarnings("unchecked")
     static boolean isAnnotationPresent(Class<?> type, Class<? extends Annotation> annotationType) {
         return isAnnotationPresent(type, true, annotationType);
     }
@@ -406,6 +414,7 @@ static boolean isAnnotationPresent(Class<?> type, Class<? extends Annotation> an
      * @param annotationClassName the class name of annotation
      * @return If any specified annotation types are present, return <code>true</code>
      */
+    @SuppressWarnings("unchecked")
     static boolean isAnnotationPresent(AnnotatedElement annotatedElement, String annotationClassName) {
         ClassLoader classLoader = annotatedElement.getClass().getClassLoader();
         Class<?> resolvedType = resolveClass(annotationClassName, classLoader);
@@ -477,6 +486,7 @@ static <T> T getDefaultValue(Annotation annotation, String attributeName) {
      * @return <code>null</code> if not found
      * @since 2.7.9
      */
+    @SuppressWarnings("unchecked")
     static <T> T getDefaultValue(Class<? extends Annotation> annotationType, String attributeName) {
         Method method = findMethod(annotationType, attributeName);
         return (T) (method == null ? null : method.getDefaultValue());