Polish apache/incubator-dubbo/#4096 : To add new module for Dubbo Event

dubbo-all/pom.xml

@@ -500,6 +500,23 @@
             <optional>true</optional>
         </dependency>
 
+        <!-- 2.7.2 new modules -->
+        <dependency>
+            <groupId>org.apache.dubbo</groupId>
+            <artifactId>dubbo-event</artifactId>
+            <version>${project.version}</version>
+            <scope>compile</scope>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.dubbo</groupId>
+            <artifactId>dubbo-metadata</artifactId>
+            <version>${project.version}</version>
+            <scope>compile</scope>
+            <optional>true</optional>
+        </dependency>
+
         <!-- Transitive dependencies -->
         <dependency>
             <groupId>org.springframework</groupId>
@@ -631,6 +648,10 @@
                                     <include>org.apache.dubbo:dubbo-metadata-report-nacos</include>
                                     <include>org.apache.dubbo:dubbo-serialization-native-hession</include>
                                     <include>org.apache.dubbo:dubbo-rpc-native-thrift</include>
+
+                                    <!-- 2.7.2 new modules -->
+                                    <include>org.apache.dubbo:dubbo-event</include>
+                                    <include>org.apache.dubbo:dubbo-metadata</include>
                                 </includes>
                             </artifactSet>
                             <transformers>
@@ -756,6 +777,19 @@
                                     <resource>META-INF/dubbo/internal/org.apache.dubbo.metadata.store.MetadataReportFactory
                                     </resource>
                                 </transformer>
+                                <!-- @since 2.7.2 -->
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
+                                    <resource>META-INF/dubbo/internal/org.apache.dubbo.event.EventDispatcher
+                                    </resource>
+                                </transformer>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
+                                    <resource>META-INF/dubbo/internal/org.apache.dubbo.metadata.export.MetadataServiceExporter
+                                    </resource>
+                                </transformer>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
+                                    <resource>META-INF/dubbo/internal/org.apache.dubbo.metadata.LocalMetadataService
+                                    </resource>
+                                </transformer>
                             </transformers>
                             <filters>
                                 <filter>

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

@@ -0,0 +1,66 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.dubbo.common.function;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * {@link Consumer} with {@link Throwable}
+ *
+ * @param <T> the source type
+ * @see Function
+ * @see Throwable
+ * @since 2.7.2
+ */
+@FunctionalInterface
+public interface ThrowableConsumer<T> {
+
+    /**
+     * Applies this function to the given argument.
+     *
+     * @param t the function argument
+     * @throws Throwable if met with any error
+     */
+    void accept(T t) throws Throwable;
+
+    /**
+     * Executes {@link ThrowableConsumer}
+     *
+     * @param t the function argument
+     * @throws RuntimeException wrappers {@link Throwable}
+     */
+    default void execute(T t) throws RuntimeException {
+        try {
+            accept(t);
+        } catch (Throwable e) {
+            throw new RuntimeException(e.getMessage(), e.getCause());
+        }
+    }
+
+    /**
+     * Executes {@link ThrowableConsumer}
+     *
+     * @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/function/ThrowableFunction.java

@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.dubbo.common.function;
+
+import java.util.function.Function;
+
+/**
+ * {@link Function} with {@link Throwable}
+ *
+ * @param <T> the source type
+ * @param <R> the return type
+ * @see Function
+ * @see Throwable
+ * @since 2.7.2
+ */
+@FunctionalInterface
+public interface ThrowableFunction<T, R> {
+
+    /**
+     * Applies this function to the given argument.
+     *
+     * @param t the function argument
+     * @return the function result
+     * @throws Throwable if met with any error
+     */
+    R apply(T t) throws Throwable;
+
+    /**
+     * Executes {@link ThrowableFunction}
+     *
+     * @param t the function argument
+     * @return the function result
+     * @throws RuntimeException wrappers {@link Throwable}
+     */
+    default R execute(T t) throws RuntimeException {
+        R result = null;
+        try {
+            result = apply(t);
+        } catch (Throwable e) {
+            throw new RuntimeException(e.getCause());
+        }
+        return result;
+    }
+
+    /**
+     * Executes {@link ThrowableFunction}
+     *
+     * @param t        the function argument
+     * @param function {@link ThrowableFunction}
+     * @param <T>      the source type
+     * @param <R>      the return type
+     * @return the result after execution
+     */
+    static <T, R> R execute(T t, ThrowableFunction<T, R> function) {
+        return function.execute(t);
+    }
+}

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

@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.dubbo.common.utils;
+
+import java.io.Serializable;
+import java.util.List;
+
+/**
+ * The default implementation of {@link Page}
+ *
+ * @since 2.7.2
+ */
+public class DefaultPage<T> implements Page<T>, Serializable {
+
+    private static final long serialVersionUID = 1099331838954070419L;
+
+    private final int requestOffset;
+
+    private final int requestSize;
+
+    private int totalSize;
+
+    private List<T> data;
+
+    public DefaultPage(int requestOffset, int requestSize) {
+        this.requestOffset = requestOffset;
+        this.requestSize = requestSize;
+    }
+
+    @Override
+    public int getRequestOffset() {
+        return requestOffset;
+    }
+
+    @Override
+    public int getRequestSize() {
+        return requestSize;
+    }
+
+    @Override
+    public int getTotalSize() {
+        return totalSize;
+    }
+
+    public void setTotalSize(int totalSize) {
+        this.totalSize = totalSize;
+    }
+
+    @Override
+    public List<T> getData() {
+        return data;
+    }
+
+    public void setData(List<T> data) {
+        this.data = data;
+    }
+}

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

@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.dubbo.common.utils;
+
+import java.util.List;
+
+/**
+ * The model class of pagination
+ *
+ * @since 2.7.2
+ */
+public interface Page<T> {
+
+    /**
+     * Gets the offset of request
+     *
+     * @return positive integer
+     */
+    int getRequestOffset();
+
+    /**
+     * Gets the size of request for query
+     *
+     * @return positive integer
+     */
+    int getRequestSize();
+
+    /**
+     * Returns the total amount of elements.
+     *
+     * @return the total amount of elements
+     */
+    int getTotalSize();
+
+    /**
+     * The data of current page
+     *
+     * @return non-null {@link List}
+     */
+    List<T> getData();
+
+    /**
+     * The size of {@link #getData() data}
+     *
+     * @return positive integer
+     */
+    default int getDataSize() {
+        return getData().size();
+    }
+
+    /**
+     * Returns whether the page has data at all.
+     *
+     * @return
+     */
+    default boolean hasData() {
+        return getDataSize() > 0;
+    }
+}