public CommandExecutorFailureEventArgs(CommandExecutorContext context, Exception exception, bool handled) : base(exception, handled)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
_context = context;
}
public CommandExecutorEventArgs(CommandExecutorContext context, object result)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
_context = context;
_result = result;
}
protected virtual object OnExecute(CommandExecutorContext context)
{
var queue = new Queue <Tuple <CommandExpression, CommandTreeNode> >();
var expression = context.Expression;
while (expression != null)
{
//查找指定路径的命令节点
var node = this.Find(expression.FullPath);
//如果指定的路径在命令树中是不存在的则抛出异常
if (node == null)
{
throw new CommandNotFoundException(expression.FullPath);
}
//将命令表达式的选项集绑定到当前命令上
if (node.Command != null)
{
expression.Options.Bind(node.Command);
}
//将找到的命令表达式和对应的节点加入队列中
queue.Enqueue(new Tuple <CommandExpression, CommandTreeNode>(expression, node));
//设置下一个待搜索的命令表达式
expression = expression.Next;
}
//如果队列为空则返回空
if (queue.Count < 1)
{
return(null);
}
//初始化第一个输入参数
var parameter = context.Parameter;
while (queue.Count > 0)
{
var entry = queue.Dequeue();
//执行队列中的命令
parameter = this.ExecuteCommand(context, entry.Item1, entry.Item2, parameter);
}
//返回最后一个命令的执行结果
return(parameter);
}
protected bool OnFailed(CommandExecutorContext context, Exception ex)
{
var args = new CommandExecutorFailureEventArgs(context, ex);
//激发“Failed”事件
this.OnFailed(args);
//输出异常信息
if (!args.ExceptionHandled && args.Exception != null)
{
this.Error.WriteLine(args.Exception);
}
return(args.ExceptionHandled);
}
protected virtual object ExecuteCommand(CommandExecutorContext context, CommandExpression expression, CommandTreeNode node, object parameter)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (node.Command == null)
{
return(null);
}
return(node.Command.Execute(this.CreateCommandContext(expression, node, parameter)));
}
public CommandExecutorExecutedEventArgs(CommandExecutorContext context, object result) : base(context, result)
{
}
public CommandExecutorExecutingEventArgs(CommandExecutorContext context, bool cancel = false) : base(context, null)
{
_cancel = cancel;
}
