[Add] Core 初步添加 Event 模块的具体实现和对 Message 的 Handler;

[Add] ThreadPoolEventExecutor, DefaultEventHandlerRegistry 添加基于线程池的事件执行器和事件处理注册器;
[Add] MessageEventHandler 添加一个尚未完成的 MessageEvent 处理类;

ContentGrabbingJi-core/src/main/java/net/lamgc/cgj/bot/event/DefaultEventHandlerRegistry.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.cgj.bot.event;
+
+import java.lang.reflect.Method;
+import java.util.*;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+/**
+ * 默认的事件处理注册器.
+ * @author LamGC
+ */
+public class DefaultEventHandlerRegistry implements EventHandlerRegistry {
+
+    private final Map<Method, Object> instanceMap = new Hashtable<>();
+    private final Map<Class<? extends EventObject>, Set<Method>> eventHandlerMap = new Hashtable<>();
+
+    @Override
+    public int registerHandler(Object handlerObject) {
+        int count = 0;
+        Class<?> handlerClass = handlerObject.getClass();
+        Method[] methods = handlerClass.getDeclaredMethods();
+        for (Method method : methods) {
+            if (!EventUtils.checkEventHandlerMethod(method)) {
+                continue;
+            }
+            addHandlerMethod(method, handlerObject);
+            count++;
+        }
+
+        return count;
+    }
+
+    private void addHandlerMethod(Method method, Object instance) {
+        instanceMap.put(method, instance);
+        Class<? extends EventObject> eventObjectClass = getParameterTypeClass(method);
+        if (!eventHandlerMap.containsKey(eventObjectClass)) {
+            eventHandlerMap.put(eventObjectClass, new CopyOnWriteArraySet<>());
+        }
+        eventHandlerMap.get(eventObjectClass).add(method);
+    }
+
+    private Class<? extends EventObject> getParameterTypeClass(Method method) {
+        Class<?> parameterType = method.getParameterTypes()[0];
+        if (EventObject.class.isAssignableFrom(parameterType)) {
+            throw new IllegalArgumentException("Wrong parameter type: " + parameterType.getName());
+        }
+        return parameterType.asSubclass(EventObject.class);
+    }
+
+    @Override
+    public Map<Method, Object> getMatchedHandlerMethod(EventObject event) {
+        Map<Method, Object> result = new HashMap<>(0);
+        Set<Method> methods = findHandleMethod(event.getClass());
+        for (Method method : methods) {
+            result.put(method, instanceMap.get(method));
+        }
+        return result;
+    }
+
+    /**
+     * 查找可处理的方法.
+     * @param eventClass 事件 Class 对象.
+     * @return 返回存储了可处理方法的集合.
+     */
+    private Set<Method> findHandleMethod(Class<? extends EventObject> eventClass) {
+        Set<Method> methods = new HashSet<>();
+        for (Class<? extends EventObject> clazz : eventHandlerMap.keySet()) {
+            if (!clazz.isAssignableFrom(eventClass)) {
+                continue;
+            }
+
+            Set<Method> eventHandlers = eventHandlerMap.get(clazz);
+            for (Method handlerMethod : eventHandlers) {
+                EventHandler handlerInfo = handlerMethod.getAnnotation(EventHandler.class);
+                if (handlerInfo.inheritable()) {
+                    methods.add(handlerMethod);
+                }
+            }
+        }
+        return methods;
+    }
+
+}

ContentGrabbingJi-core/src/main/java/net/lamgc/cgj/bot/event/MessageEventHandler.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.cgj.bot.event;
+
+import net.lamgc.cgj.bot.framework.message.AbstractMessageEvent;
+
+/**
+ * 消息事件处理类.
+ * <p> 该类将接受原始消息事件, 经消息处理器处理后返回.
+ * @author LamGC
+ */
+public class MessageEventHandler {
+
+    @EventHandler(inheritable = true)
+    public void onHandle(AbstractMessageEvent event) {
+
+    }
+
+}

ContentGrabbingJi-core/src/main/java/net/lamgc/cgj/bot/event/ThreadPoolEventExecutor.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.cgj.bot.event;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.ThreadPoolExecutor;
+
+/**
+ * 基于线程池, 以事件为单位的异步事件执行器.
+ * <p> 以事件为单位对于 ContentGrabbingJi 来说是实现难度低, 还很合适的,
+ * ContentGrabbingJi 只会注册一个 Handler, 所以依然类似于一个 Handler 一个线程.
+ * @author LamGC
+ */
+public class ThreadPoolEventExecutor implements EventExecutor {
+
+    private final ThreadPoolExecutor threadExecutor;
+    private final EventHandlerRegistry registry;
+
+    /**
+     * 构造线程池事件执行器.
+     * @param threadExecutor 执行器所使用的线程池.
+     * @param registry 事件处理注册器.
+     */
+    public ThreadPoolEventExecutor(ThreadPoolExecutor threadExecutor, EventHandlerRegistry registry) {
+        this.threadExecutor = threadExecutor;
+        this.registry = registry;
+    }
+
+    @Override
+    public void execute(EventObject event) {
+        threadExecutor.execute(new ExecuteRunnable(event, registry.getMatchedHandlerMethod(event)));
+    }
+
+    @Override
+    public boolean isAsync() {
+        return true;
+    }
+
+    /**
+     * 按事件为单位的事件处理执行类.
+     */
+    private final static class ExecuteRunnable implements Runnable {
+
+        private final static Logger log = LoggerFactory.getLogger(ExecuteRunnable.class);
+
+        private final EventObject event;
+        private final Map<Method, Object> handlerMethods;
+
+        private ExecuteRunnable(EventObject event, Map<Method, Object> handlerMethods) {
+            this.event = Objects.requireNonNull(event);
+            this.handlerMethods = Objects.requireNonNull(handlerMethods);
+        }
+
+        @Override
+        public void run() {
+            if (event instanceof Cancelable) {
+                runCancelableEvent();
+            } else {
+                runOrdinaryEvent();
+            }
+        }
+
+        /**
+         * 运行可取消事件.
+         */
+        private void runCancelableEvent() {
+            Cancelable cancelable = (Cancelable) event;
+            for (Method handlerMethod : handlerMethods.keySet()) {
+                if (cancelable.canceled()) {
+                    log.warn("事件 {} 已取消, 终止处理.", event);
+                    break;
+                }
+
+                try {
+                    Object instance = handlerMethods.get(handlerMethod);
+                    checkInstance(handlerMethod, instance);
+                    handlerMethod.invoke(instance, event);
+                } catch (InvocationTargetException e) {
+                    log.error("Handler '" + handlerMethod.getDeclaringClass() + "." +
+                            handlerMethod.getName() + "()'" +" throws an uncaught exception when handling an event",
+                            e);
+                } catch (Exception e) {
+                    log.error("Exception in handler '" + handlerMethod.getDeclaringClass() + "." +
+                            handlerMethod.getName() + "()' call", e);
+                }
+            }
+        }
+
+        /**
+         * 运行普通事件.
+         */
+        private void runOrdinaryEvent() {
+            handlerMethods.forEach((method, instance) -> {
+                try {
+                    checkInstance(method, instance);
+                    method.invoke(instance, event);
+                } catch (InvocationTargetException e) {
+                    log.error("Handler '" + method.getDeclaringClass() + "." + method.getName() + "()'" +
+                            " throws an uncaught exception when handling an event", e);
+                } catch (Exception e) {
+                    log.error("Exception in handler '" + method.getDeclaringClass() + "." +
+                            method.getName() + "()' call", e);
+                }
+            });
+        }
+
+        private void checkInstance(Method method, Object object) {
+            if (!method.getDeclaringClass().isAssignableFrom(object.getClass())) {
+                throw new ClassCastException("Method declaration class does not match call instance (Method: '" +
+                        method.getDeclaringClass().getName() + "', Instance: '" + object.getClass().getName() + "')");
+            }
+        }
+
+    }
+
+}