sharding-jdbc中RootInvokeHook的用法
本篇内容介绍了"sharding-jdbc中RootInvokeHook的用法"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
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本文主要研究一下sharding-jdbc的RootInvokeHook
RootInvokeHook
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-execute/src/main/java/org/apache/shardingsphere/core/execute/hook/RootInvokeHook.java
public interface RootInvokeHook { /** * Handle when root invoke started. */ void start(); /** * Handle when root invoke finished. * * @param connectionCount connection count */ void finish(int connectionCount);}RootInvokeHook定义了start、finish接口
SPIRootInvokeHook
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-execute/src/main/java/org/apache/shardingsphere/core/execute/hook/SPIRootInvokeHook.java
public final class SPIRootInvokeHook implements RootInvokeHook { private final Collection rootInvokeHooks = NewInstanceServiceLoader.newServiceInstances(RootInvokeHook.class); static { NewInstanceServiceLoader.register(RootInvokeHook.class); } @Override public void start() { for (RootInvokeHook each : rootInvokeHooks) { each.start(); } } @Override public void finish(final int connectionCount) { for (RootInvokeHook each : rootInvokeHooks) { each.finish(connectionCount); } }} SPIRootInvokeHook实现了RootInvokeHook接口，它使用NewInstanceServiceLoader注册了RootInvokeHook；rootInvokeHooks集合由NewInstanceServiceLoader.newServiceInstances创建；start方法遍历rootInvokeHooks，执行其start方法；finish方法则遍历rootInvokeHooks，执行器finish方法
NewInstanceServiceLoader
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/spi/NewInstanceServiceLoader.java
@NoArgsConstructor(access = AccessLevel.PRIVATE)public final class NewInstanceServiceLoader { private static final Map>> SERVICE_MAP = new HashMap<>(); /** * Register SPI service into map for new instance. * * @param service service type * @param type of service */ public static void register(final Class service) { for (T each : ServiceLoader.load(service)) { registerServiceClass(service, each); } } @SuppressWarnings("unchecked") private static void registerServiceClass(final Class service, final T instance) { Collection> serviceClasses = SERVICE_MAP.get(service); if (null == serviceClasses) { serviceClasses = new LinkedHashSet<>(); } serviceClasses.add(instance.getClass()); SERVICE_MAP.put(service, serviceClasses); } /** * New service instances. * * @param service service class * @param type of service * @return service instances */ @SneakyThrows @SuppressWarnings("unchecked") public static Collection newServiceInstances(final Class service) { Collection result = new LinkedList<>(); if (null == SERVICE_MAP.get(service)) { return result; } for (Class each : SERVICE_MAP.get(service)) { result.add((T) each.newInstance()); } return result; }} NewInstanceServiceLoader的register方法会使用ServiceLoader.load加载指定service的实现类，然后调用registerServiceClass注册到SERVICE_MAP；newServiceInstances则找到指定service的实现类，然后挨个创建实例
OpenTracingRootInvokeHook
incubator-shardingsphere-4.0.0-RC1/sharding-opentracing/src/main/java/org/apache/shardingsphere/opentracing/hook/OpenTracingRootInvokeHook.java
public final class OpenTracingRootInvokeHook implements RootInvokeHook { public static final String ACTIVE_SPAN_CONTINUATION = "ACTIVE_SPAN_CONTINUATION"; private static final String OPERATION_NAME = "/" + ShardingTags.COMPONENT_NAME + "/rootInvoke/"; private ActiveSpan activeSpan; @Override public void start() { activeSpan = ShardingTracer.get().buildSpan(OPERATION_NAME).withTag(Tags.COMPONENT.getKey(), ShardingTags.COMPONENT_NAME).startActive(); ShardingExecuteDataMap.getDataMap().put(ACTIVE_SPAN_CONTINUATION, activeSpan.capture()); } @Override public void finish(final int connectionCount) { activeSpan.setTag(ShardingTags.CONNECTION_COUNT.getKey(), connectionCount).deactivate(); }}OpenTracingRootInvokeHook实现了RootInvokeHook接口，其start方法创建并启动activeSpan；finish方法则设置CONNECTION_COUNT，然后标记activeSpan为deactivate
AbstractConnectionAdapter
incubator-shardingsphere-4.0.0-RC1/sharding-jdbc/sharding-jdbc-core/src/main/java/org/apache/shardingsphere/shardingjdbc/jdbc/adapter/AbstractConnectionAdapter.java
@Getterpublic abstract class AbstractConnectionAdapter extends AbstractUnsupportedOperationConnection { private final Multimap cachedConnections = LinkedHashMultimap.create(); private boolean autoCommit = true; private boolean readOnly = true; private volatile boolean closed; private int transactionIsolation = TRANSACTION_READ_UNCOMMITTED; private final ForceExecuteTemplate forceExecuteTemplate = new ForceExecuteTemplate<>(); private final ForceExecuteTemplate> forceExecuteTemplateForClose = new ForceExecuteTemplate<>(); private final RootInvokeHook rootInvokeHook = new SPIRootInvokeHook(); private final ShardingTransactionManager shardingTransactionManager; private ShardingTransactionManagerEngine shardingTransactionManagerEngine; private TransactionType transactionType; protected AbstractConnectionAdapter(final ShardingTransactionManagerEngine shardingTransactionManagerEngine, final TransactionType transactionType) { rootInvokeHook.start(); this.transactionType = transactionType; this.shardingTransactionManagerEngine = shardingTransactionManagerEngine; shardingTransactionManager = shardingTransactionManagerEngine.getTransactionManager(transactionType); } //...... public final void close() throws SQLException { closed = true; MasterVisitedManager.clear(); TransactionTypeHolder.clear(); int connectionSize = cachedConnections.size(); try { forceExecuteTemplateForClose.execute(cachedConnections.entries(), new ForceExecuteCallback>() { @Override public void execute(final Entry cachedConnections) throws SQLException { cachedConnections.getValue().close(); } }); } finally { cachedConnections.clear(); rootInvokeHook.finish(connectionSize); } } //......} AbstractConnectionAdapter的构造器会执行rootInvokeHook.start()；其close方法会执行rootInvokeHook.finish(connectionSize)
小结
RootInvokeHook定义了start、finish接口；SPIRootInvokeHook实现了RootInvokeHook接口，它使用NewInstanceServiceLoader注册了RootInvokeHook；rootInvokeHooks集合由NewInstanceServiceLoader.newServiceInstances创建；start方法遍历rootInvokeHooks，执行其start方法；finish方法则遍历rootInvokeHooks，执行器finish方法
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