本文主要研究一下dubbo的CommandExecutor
dubbo-2.7.2/dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/command/CommandExecutor.java
public interface CommandExecutor { /** * Execute one command and return the execution result * * @param commandContext command context * @return command execution result * @throws NoSuchCommandException */ String execute(CommandContext commandContext) throws NoSuchCommandException; }
dubbo-2.7.2/dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/command/CommandContext.java
public class CommandContext { private String commandName; private String[] args; private Channel remote; private boolean isHttp; private Object originRequest; public CommandContext(String commandName) { this.commandName = commandName; } public CommandContext(String commandName, String[] args, boolean isHttp) { this.commandName = commandName; this.args = args; this.isHttp = isHttp; } public String getCommandName() { return commandName; } public void setCommandName(String commandName) { this.commandName = commandName; } public String[] getArgs() { return args; } public void setArgs(String[] args) { this.args = args; } public Channel getRemote() { return remote; } public void setRemote(Channel remote) { this.remote = remote; } public boolean isHttp() { return isHttp; } public void setHttp(boolean http) { isHttp = http; } public Object getOriginRequest() { return originRequest; } public void setOriginRequest(Object originRequest) { this.originRequest = originRequest; } }
dubbo-2.7.2/dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/command/DefaultCommandExecutor.java
public class DefaultCommandExecutor implements CommandExecutor { @Override public String execute(CommandContext commandContext) throws NoSuchCommandException { BaseCommand command = null; try { command = ExtensionLoader.getExtensionLoader(BaseCommand.class).getExtension(commandContext.getCommandName()); } catch (Throwable throwable) { //can't find command } if (command == null) { throw new NoSuchCommandException(commandContext.getCommandName()); } return command.execute(commandContext, commandContext.getArgs()); } }
CommandExecutor定义了execute方法,其方法传入CommandContext参数;CommandContext定义了commandName、args、remote、isHttp、originRequest参数;DefaultCommandExecutor实现了CommandExecutor接口,其execute方法会根据commandName通过ExtensionLoader来加载对应的comamnd,然后执行command的execute方法