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使用guava AbstractScheduledService(Using guava AbstractScheduledService)

 我正在尝试使用guava AbstractScheduledService定期执行一些任务：  
public class MyService extends AbstractScheduledService {

    public MyService() {

    }

    @Override
    protected void runOneIteration() {
        doStuff();
    }

    private void doStuff() {
    // Do stuff
    }

    @Override
    protected Scheduler scheduler() {
        return Scheduler.newFixedRateSchedule(0, 8, TimeUnit.HOURS);
    }

}
 
 所以这项服务应该每8小时定期执行一些任务，但实际上并不是这样。 继承的isRunning()方法返回false，并且永远不会调用runOneIteration()方法。  
 我已经设法通过从我的服务构造函数调用startAsync()方法（从父类继承startAsync()来使它工作，但我没有看到任何引用说这是应该工作的方式。  
 我错过了什么吗？ 这是AbstractScheduledService工作方式吗？ 

I'm trying to execute some task periodically using guava AbstractScheduledService : 
public class MyService extends AbstractScheduledService {

    public MyService() {

    }

    @Override
    protected void runOneIteration() {
        doStuff();
    }

    private void doStuff() {
    // Do stuff
    }

    @Override
    protected Scheduler scheduler() {
        return Scheduler.newFixedRateSchedule(0, 8, TimeUnit.HOURS);
    }

}
 
So this service should execute some task periodically every 8 hours but it never actually does. The inherited isRunning() method returns false and the runOneIteration() method never gets invoked. 
I have managed to make it work by calling the startAsync() method (inherited from parent class) from my service constructor but I don't see any reference saying this is the way it should work. 
Have I missed something here? Is this the way the AbstractScheduledService works?

原文：https://stackoverflow.com/questions/25499811

更新时间：2023-07-12 21:07

最满意答案

 是的，不幸的是，这需要一些基于反思的黑客才能实现。 这里是一个示例扩展类：  
 PropertyGridExtensionHacks.cs  
using System.Reflection;
using System.Windows.Forms;

namespace PropertyGridExtensionHacks
{
    public static class PropertyGridExtensions
    {
        /// <summary>
        /// Gets the (private) PropertyGridView instance.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <returns>The PropertyGridView instance.</returns>
        private static object GetPropertyGridView(PropertyGrid propertyGrid)
        { 
            //private PropertyGridView GetPropertyGridView();
            //PropertyGridView is an internal class...
            MethodInfo methodInfo = typeof(PropertyGrid).GetMethod("GetPropertyGridView", BindingFlags.NonPublic | BindingFlags.Instance);
            return methodInfo.Invoke(propertyGrid, new object[] {});
        }

        /// <summary>
        /// Gets the width of the left column.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <returns>
        /// The width of the left column.
        /// </returns>
        public static int GetInternalLabelWidth(this PropertyGrid propertyGrid)
        {
            //System.Windows.Forms.PropertyGridInternal.PropertyGridView
            object gridView = GetPropertyGridView(propertyGrid);

            //protected int InternalLabelWidth
            PropertyInfo propInfo = gridView.GetType().GetProperty("InternalLabelWidth", BindingFlags.NonPublic | BindingFlags.Instance);
            return (int)propInfo.GetValue(gridView);
        }

        /// <summary>
        /// Moves the splitter to the supplied horizontal position.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <param name="xpos">The horizontal position.</param>
        public static void MoveSplitterTo(this PropertyGrid propertyGrid, int xpos)
        {
            //System.Windows.Forms.PropertyGridInternal.PropertyGridView
            object gridView = GetPropertyGridView(propertyGrid);

            //private void MoveSplitterTo(int xpos);
            MethodInfo methodInfo = gridView.GetType().GetMethod("MoveSplitterTo", BindingFlags.NonPublic | BindingFlags.Instance);
            methodInfo.Invoke(gridView, new object[] { xpos });
        }
    }
}
 
 要移动拆分器位置，请使用MoveSplitterTo扩展方法。 使用GetInternalLabelWidth扩展方法来获取分离器的实际位置。 请注意，我观察到，直到SelectedObject被分配并且PropertyGrid未显示，GetInternalLabelWidth返回（-1）。  
 使用示例：  
using PropertyGridExtensionHacks;
//...

    private void buttonMoveSplitter_Click(object sender, EventArgs e)
    {
        int splitterPosition = this.propertyGrid1.GetInternalLabelWidth();
        this.propertyGrid1.MoveSplitterTo(splitterPosition + 10);
    }

Yes, unfortunately this requires some reflection based hacks in order to be achieved. Here is a sample extensions class: 
PropertyGridExtensionHacks.cs 
using System.Reflection;
using System.Windows.Forms;

namespace PropertyGridExtensionHacks
{
    public static class PropertyGridExtensions
    {
        /// <summary>
        /// Gets the (private) PropertyGridView instance.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <returns>The PropertyGridView instance.</returns>
        private static object GetPropertyGridView(PropertyGrid propertyGrid)
        { 
            //private PropertyGridView GetPropertyGridView();
            //PropertyGridView is an internal class...
            MethodInfo methodInfo = typeof(PropertyGrid).GetMethod("GetPropertyGridView", BindingFlags.NonPublic | BindingFlags.Instance);
            return methodInfo.Invoke(propertyGrid, new object[] {});
        }

        /// <summary>
        /// Gets the width of the left column.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <returns>
        /// The width of the left column.
        /// </returns>
        public static int GetInternalLabelWidth(this PropertyGrid propertyGrid)
        {
            //System.Windows.Forms.PropertyGridInternal.PropertyGridView
            object gridView = GetPropertyGridView(propertyGrid);

            //protected int InternalLabelWidth
            PropertyInfo propInfo = gridView.GetType().GetProperty("InternalLabelWidth", BindingFlags.NonPublic | BindingFlags.Instance);
            return (int)propInfo.GetValue(gridView);
        }

        /// <summary>
        /// Moves the splitter to the supplied horizontal position.
        /// </summary>
        /// <param name="propertyGrid">The property grid.</param>
        /// <param name="xpos">The horizontal position.</param>
        public static void MoveSplitterTo(this PropertyGrid propertyGrid, int xpos)
        {
            //System.Windows.Forms.PropertyGridInternal.PropertyGridView
            object gridView = GetPropertyGridView(propertyGrid);

            //private void MoveSplitterTo(int xpos);
            MethodInfo methodInfo = gridView.GetType().GetMethod("MoveSplitterTo", BindingFlags.NonPublic | BindingFlags.Instance);
            methodInfo.Invoke(gridView, new object[] { xpos });
        }
    }
}
 
To move the splitter position use the MoveSplitterTo extension method. Use the GetInternalLabelWidth extension method to get the actual position of the splitter. Please note that I observed that until the SelectedObject is assigned and the PropertyGrid was not shown, GetInternalLabelWidth returns (-1). 
Sample use: 
using PropertyGridExtensionHacks;
//...

    private void buttonMoveSplitter_Click(object sender, EventArgs e)
    {
        int splitterPosition = this.propertyGrid1.GetInternalLabelWidth();
        this.propertyGrid1.MoveSplitterTo(splitterPosition + 10);
    }

使用guava AbstractScheduledService(Using guava AbstractScheduledService)

最满意答案

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