dubbo SPI 源码

  • 2022-10-20
  • 浏览 (425)

dubbo SPI 代码

文件路径:/dubbo-common/src/main/java/org/apache/dubbo/common/extension/SPI.java

/*
 * 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.extension;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Marker for extension interface
 * <p/>
 * Changes on extension configuration file <br/>
 * Use <code>Protocol</code> as an example, its configuration file 'META-INF/dubbo/com.xxx.Protocol' is changed from: <br/>
 * <pre>
 *     com.foo.XxxProtocol
 *     com.foo.YyyProtocol
 * </pre>
 * <p>
 * to key-value pair <br/>
 * <pre>
 *     xxx=com.foo.XxxProtocol
 *     yyy=com.foo.YyyProtocol
 * </pre>
 * <br/>
 * The reason for this change is:
 * <p>
 * If there's third party library referenced by static field or by method in extension implementation, its class will
 * fail to initialize if the third party library doesn't exist. In this case, dubbo cannot figure out extension's id
 * therefore cannot be able to map the exception information with the extension, if the previous format is used.
 * <p/>
 * For example:
 * <p>
 * Fails to load Extension("mina"). When user configure to use mina, dubbo will complain the extension cannot be loaded,
 * instead of reporting which extract extension implementation fails and the extract reason.
 * </p>
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface SPI {

    /**
     * default extension name
     */
    String value() default "";

    /**
     * scope of SPI, default value is application scope.
     */
    ExtensionScope scope() default ExtensionScope.APPLICATION;
}

相关信息

dubbo 源码目录

相关文章

dubbo Activate 源码

dubbo Adaptive 源码

dubbo AdaptiveClassCodeGenerator 源码

dubbo DisableInject 源码

dubbo DubboInternalLoadingStrategy 源码

dubbo DubboLoadingStrategy 源码

dubbo ExtensionAccessor 源码

dubbo ExtensionAccessorAware 源码

dubbo ExtensionDirector 源码

dubbo ExtensionFactory 源码

0  赞