Ok, so what I found is that you can make UDF functions in mysql that can do anything but need to be written in C/C++. They can be then called from triggers on updates in database and notify your application when update happened. I saw that there are some security concerns. I did not use … Read more
It seems that whenever you use header/footer views in a listview, your ListView gets wrapped with a HeaderViewListAdapter. You can fix this using the below code: ((YourAdapter)((HeaderViewListAdapter)lv.getAdapter()).getWrappedAdapter()).notifyDataSetChanged();
There is one more reason that notify can return: spurious wakeup. This is an unlikely but possible thing, because preventing spurious wakeups is very expensive on some hardware/OS combinations. Because of this you always have to call wait() in a loop and re-check the condition that you are waiting for. During this work it’s easy … Read more
You have noted correctly that notifyAll must be called from a synchronized block. However, in your case, because of auto-boxing, the object you synchronized on is not the same instance that you invoked notifyAll on. In fact, the new, incremented foo instance is still confined to the stack, and no other threads could possibly be … Read more
I use i3 on Ubuntu 18.04. My way to solve this is: * * * * * XDG_RUNTIME_DIR=/run/user/$(id -u) notify-send Hey “this is dog!” Edit 2020: I still use it on Ubuntu 20.04.
Locking is about protecting shared data. The lock is on the data structure being protected. The threads are the things accessing the data structure. The locks are on the data structure object in order to keep the threads from accessing the data structure in an unsafe way. Any object can be used as an intrinsic … Read more
Because, you wait on a given Object (or specifically, its monitor) to use this functionality. I think you may be mistaken on how these methods work. They’re not simply at a Thread-granularity level, i.e. it is not a case of just calling wait() and being woken up by the next call to notify(). Rather, you … Read more
I am just having hard time to understand concept behind putting wait() in object class For this questions sake consider as if wait() and notifyAll() are in thread class In the Java language, you wait() on a particular instance of an Object – a monitor assigned to that object to be precise. If you want … Read more
Define a callback interface to receive whatever parameters you want to pass along in the completion notification. Then invoke it at the end of the task. You could even write a general wrapper for Runnable tasks, and submit these to ExecutorService. Or, see below for a mechanism built into Java 8. class CallbackTask implements Runnable … Read more
The wait() and notify() methods are designed to provide a mechanism to allow a thread to block until a specific condition is met. For this I assume you’re wanting to write a blocking queue implementation, where you have some fixed size backing-store of elements. The first thing you have to do is to identify the … Read more