feat: 开发线程池拒绝策略及 SPI 方式集成.

dynamic-threadpool-spring-boot-starter/src/main/java/io/dynamic/threadpool/starter/spi/rejected/CustomRejectedExecutionHandler.java

@@ -0,0 +1,34 @@
+package io.dynamic.threadpool.starter.spi.rejected;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.concurrent.RejectedExecutionHandler;
+
+/**
+ * 自定义拒绝策略
+ *
+ * @author chen.ma
+ * @date 2021/7/10 23:51
+ */
+public interface CustomRejectedExecutionHandler {
+
+    /**
+     * 生成拒绝策略
+     *
+     * @return
+     */
+    RejectedExecutionHandlerWrap generateRejected();
+
+    @Getter
+    @Setter
+    @AllArgsConstructor
+    class RejectedExecutionHandlerWrap {
+
+        private Integer type;
+
+        private RejectedExecutionHandler rejectedExecutionHandler;
+
+    }
+}

dynamic-threadpool-spring-boot-starter/src/main/java/io/dynamic/threadpool/starter/toolkit/thread/RejectedTypeEnum.java

@@ -0,0 +1,86 @@
+package io.dynamic.threadpool.starter.toolkit.thread;
+
+import io.dynamic.threadpool.starter.spi.DynamicTpServiceLoader;
+import io.dynamic.threadpool.starter.spi.rejected.CustomRejectedExecutionHandler;
+
+import java.util.*;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.stream.Stream;
+
+/**
+ * 拒绝策略类型枚举
+ *
+ * @author chen.ma
+ * @date 2021/7/10 23:16
+ */
+public enum RejectedTypeEnum {
+
+    /**
+     * 被拒绝任务的程序由主线程执行
+     */
+    CALLER_RUNS_POLICY(1, new ThreadPoolExecutor.CallerRunsPolicy()),
+
+    /**
+     * 被拒绝任务的处理程序, 抛出异常
+     */
+    ABORT_POLICY(2, new ThreadPoolExecutor.AbortPolicy()),
+
+    /**
+     * 被拒绝任务的处理程序, 默默地丢弃被拒绝的任务。
+     */
+    DISCARD_POLICY(3, new ThreadPoolExecutor.DiscardPolicy()),
+
+    /**
+     * 被拒绝任务的处理程序, 它丢弃最早的未处理请求, 然后重试
+     */
+    DISCARD_OLDEST_POLICY(4, new ThreadPoolExecutor.DiscardOldestPolicy()),
+
+    /**
+     * 发生拒绝事件时, 添加新任务并运行最早的任务
+     */
+    RUNS_OLDEST_TASK_POLICY(5, RejectedPolicies.runsOldestTaskPolicy()),
+
+    /**
+     * 使用阻塞方法将拒绝任务添加队列, 可保证任务不丢失
+     */
+    SYNC_PUT_QUEUE_POLICY(6, RejectedPolicies.syncPutQueuePolicy());
+
+    /**
+     * 类型
+     */
+    public Integer type;
+
+    /**
+     * 线程池拒绝策略
+     */
+    public RejectedExecutionHandler rejectedHandler;
+
+    RejectedTypeEnum(Integer type, RejectedExecutionHandler rejectedHandler) {
+        this.type = type;
+        this.rejectedHandler = rejectedHandler;
+    }
+
+    public static RejectedExecutionHandler createPolicy(Integer type) {
+        Optional<RejectedExecutionHandler> rejectedTypeEnum = Stream.of(RejectedTypeEnum.values())
+                .filter(each -> Objects.equals(type, each.type))
+                .map(each -> each.rejectedHandler)
+                .findFirst();
+
+        // 使用 SPI 匹配拒绝策略
+        RejectedExecutionHandler resultRejected = rejectedTypeEnum.orElseGet(() -> {
+            Collection<CustomRejectedExecutionHandler> customRejectedExecutionHandlers = DynamicTpServiceLoader
+                    .getSingletonServiceInstances(CustomRejectedExecutionHandler.class);
+            Optional<RejectedExecutionHandler> customRejected = customRejectedExecutionHandlers.stream()
+                    .map(each -> each.generateRejected())
+                    .filter(each -> Objects.equals(type, each.getType()))
+                    .map(each -> each.getRejectedExecutionHandler())
+                    .findFirst();
+
+            return customRejected.orElse(ABORT_POLICY.rejectedHandler);
+        });
+
+        return resultRejected;
+    }
+
+}