OnDisable() Force

Is there a way to force your plugin to automatically be the last one to be unloaded from the server?

 

97WaterPolo

Why does it need to be the last one?

 

97WaterPolo, i believe there is a property of the plugin manager that may be able to do this.

 

mythbusterma I'd just like to note that replies like that just don't contribute to threads. Please only post constructive things.

 

Code0 If we know why then we can maybe find another solution.

 

This, also, you're being even less constructive. Your backseat moderation is almost laughable in its uselessness.

I ask because there's probably a much easier solution to this issue.

 

97WaterPolo, after experimenting, I'm pretty sure there is no way. You can set the order in which they enable, but not disable

 

97WaterPolo You can load before plugins but I am not sure about disabling after.

 

97WaterPolo
In order to do this, you must understand how all plugins are disabled.

The collection of plugins in question is at this line: https://github.com/Bukkit/Bukkit/bl...rg/bukkit/plugin/SimplePluginManager.java#L43

Plugins are disabled by filling an empty array with the contents of the collection synchronously: https://github.com/Bukkit/Bukkit/bl...rg/bukkit/plugin/SimplePluginManager.java#L43

I haven't investigated why it is synchronized, or why it decidedly supports multithreading yet, but nevertheless, the array returned by that method is iterated by this method: https://github.com/Bukkit/Bukkit/bl...g/bukkit/plugin/SimplePluginManager.java#L413

But, here is the gotcha: the array is iterated backwards. Because ArrayList#toArray(T[]) returns the array in insertion order, you would need to insert the plugin FIRST in order to have it disabled last.

This is quite simple, as it is a matter of swapping the position of your plugin and the first plugin after all the plugins have finished loading into the list. You can be sure that it runs after all the plugins load, and before they unload by checking for the server's shutdown message. I have not investigated thoroughly all the conventional ways, but I believe this is the only way.

To avoid having a Thread that would continuously waste server resources to check the output, we will add a Handler to the server's logger to watch the output.

PHP:

@Override public void onEnable() {
    this.getServer().getLogger().addHandler(new Handler() {
        @Override public void close() {}
        @Override public void flush() {}
        @Override public void publish(LogRecord record) {
            if (record.getMessage().equals("Stopping server") {
                reorderPlugins();
            }
        }
        @Override reportError(String msg, Exception ex, int code) {}
    });
}

There! now we only need to implement the reorderPlugins() method.

PHP:

class FieldMod {
    private final Field field;
    public FieldMod(Field field) { this.field = field; }
    public static FieldMod of(Class<?> c, String field) {
        try {
            Field field = c.getDeclaredField(field);
            field.setAccessible(true);
            return new FieldMod(field);
        } catch (Exception x) {
            x.printStackTrace();
            return null;
        }
    }
    public Object get(Object o) throws Exception {
        return this.field.get(o);
    }
 
    public void set(Object o, Object value) throws Exception {
        this.field.set(o, value);
    }
 
    public Field get() {
        return this.field;
    }
}
 
private static final FieldMod SETTER = FieldMod.of(Unsafe.class, "theUnsafe");
private static final FieldMod LIST = FieldMod.of(SimplePluginManager.class, "plugins");
 
// This should be in the plugin main class
public void reorderPlugins() {
    try {
        PluginManager instance = Bukkit.getServer().getPluginManager();
        Unsafe unsafe = SETTER.get(null);
        List<Plugin> list = LIST.get(instance);
 
        Plugin old = list.get(0);
        if (old != this) { // Just to make sure this is not the first plugin already
            int index = list.indexOf(this);
            list.set(0, this);
            list.set(index, old);
        } else return;
 
        long off = unsafe.objectFieldOffset(LIST.get());
        unsafe.putObject(instance, off, list);
    } catch (Exception x) {
        x.printStackTrace();
    }
}

Try it out and see if it works.

The reason we get sun.misc.Unsafe because it is a large hassle to set the field without it. You need to rewrite the modifiers for the Field object in order to not get an exception thrown when reflecting a final field.

Basically what we are doing is setting the plugin to the first element, and setting the plugin that was originally there to our plugin's original spot. When the plugins are disabled, it starts from the last element in the list, and then iterates backwards, and the last one should be the first element, which we set to our plugin. It's pretty hacky but it should work, good luck.

Edit: Oops, Handler might be called after the string has been formatted, you should use contains(...) a the risk of false positives in plugins that use the same String, or use regex to check for the time/date/and other data prepending the string.

 

xTrollxDudex
Geesh, I was hoping there was just a simple fix. Thanks for explaining it! Will try it and see if it works!

 

Pho

Php ;-;