Fluent style builder API support(#3431)

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/annotation/Method.java

@@ -0,0 +1,95 @@
+package org.apache.dubbo.config.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import org.apache.dubbo.common.Constants;
+
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.METHOD})
+@Inherited
+public @interface Method {
+
+  /**
+   * Timeout value for service invocation, default value is 0
+   */
+  int timeout() default 0;
+
+  /**
+   * Service invocation retry times
+   *
+   * @see Constants#DEFAULT_RETRIES
+   */
+  int retries() default Constants.DEFAULT_RETRIES;
+
+  /**
+   * Load balance strategy, legal values include: random, roundrobin, leastactive
+   *
+   * @see Constants#DEFAULT_LOADBALANCE
+   */
+  String loadbalance() default Constants.DEFAULT_LOADBALANCE;
+
+  /**
+   * Whether to enable async invocation, default value is false
+   */
+  boolean async() default false;
+
+  /**
+   * Maximum active requests allowed, default value is 0
+   */
+  int actives() default 0;
+
+  /**
+   * Whether the async request has already been sent, the default value is false
+   */
+  boolean sent() default false;
+
+  /**
+   * Maximum concurrent executes for the service, default value is 0 - no limits
+   */
+  int executes() default 0;
+
+  /**
+   * Whether the service is deprecated, default value is false
+   */
+  boolean deprecated() default false;
+
+  /**
+   * Enable/Disable cluster sticky policy, default value is false.
+   */
+  boolean sticky() default false;
+
+  /**
+   * Method result need return, when async is true.default value is true.
+   */
+  boolean needReturn() default true;
+
+  /**
+   * Specify cache implementation for service invocation, legal values include: lru, threadlocal, jcache
+   */
+  String cache() default "";
+
+  /**
+   * Whether to use JSR303 validation, legal values are: true, false
+   */
+  boolean validation() default false;
+
+  /**
+   * Method return trigger. return attribute must be true
+   */
+  String onReturn() default "";
+
+  /**
+   * Method invoke trigger.
+   */
+  String onInvoke() default "";
+
+  /**
+   * Method on error trigger.return attribute must be true.
+   */
+  String onThrow() default "";
+}

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/builders/AbstractBuilder.java

@@ -0,0 +1,69 @@
+/*
+ * 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.config.builders;
+
+import org.apache.dubbo.common.utils.StringUtils;
+import org.apache.dubbo.config.AbstractConfig;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * AbstractBuilder
+ *
+ * @since 2.7
+ */
+public abstract class AbstractBuilder<T extends AbstractConfig, B extends AbstractBuilder> {
+    /**
+     * The config id
+     */
+    protected String id;
+    protected String prefix;
+
+    protected B id(String id) {
+        this.id = id;
+        return getThis();
+    }
+
+    protected B prefix(String prefix) {
+        this.prefix = prefix;
+        return getThis();
+    }
+
+    protected abstract B getThis();
+
+    protected static Map<String, String> appendParameter(Map<String, String> parameters, String key, String value) {
+        if (parameters == null) {
+            parameters = new HashMap<>();
+        }
+        parameters.put(key, value);
+        return parameters;
+    }
+
+    protected static Map<String, String> appendParameters(Map<String, String> parameters, Map<String, String> appendParameters) {
+        if (parameters == null) {
+            parameters = new HashMap<>();
+        }
+        parameters.putAll(appendParameters);
+        return parameters;
+    }
+
+    protected void build(T instance) {
+        if (!StringUtils.isEmpty(id)) instance.setId(id);
+        if (!StringUtils.isEmpty(prefix)) instance.setPrefix(prefix);
+    }
+}