synchronization

I am creating one android test application , in which i have one button. On button click ,i want to synchronize phonebook records with my local database.If record in phone book is not in db table then insert it , otherwise leave it as it is. so how can i do this? For getting contact list from your phone book you need write permission in AndroidManifest.XML (i.e. android.permission.READ_CONTACTS ) .And you can collect contact list using following method. ShowContact() { ArrayList<String> nameList; ArrayList<String> phoneNoList; ContentResolver cr = getContentResolver(); Cursor cur = cr.query

I want to detect a rising edge of a signal from a flip-flop AA to BB +----+ A ----------------| |----- OUT +----+ | BB | B ----| |------|> | | AA | +----+ clk ----|> | +----+ Verilog code: module edge_detect ( input A, input B, input clk, output OUT ); reg AA; reg BB; always @(posedge clk) begin AA <= B; end always @(posedge AA)begin BB <= A; end assign OUT = BB; endmodule The output of AA is used as a clock to BB saying that AA has done its job and then BB can now continue its operation. I rarely see this code. Is this a good practice? If not, are there any other proper way to detect an edge

I wrote a simple program solving the Readers-Writers problem using semaphores. It runs perfectly on Linux os, but when I run it on my Mac osX I get unexpected results and I can't figure out why. My Program: #include <semaphore.h> #include <sys/types.h> #include <stdio.h> #include <pthread.h> #include <unistd.h> void* function1(void* val); void* function2(void* val); // shared values volatile int X; volatile int Y; // declare semaphores sem_t s1; sem_t s2; main() { void* status; pthread_t thread1; pthread_t thread2; srand(time(NULL)); // initialize semaphores to zero sem_init(&s1, 0, 0); sem

For a travel booking web application, where there are 100 concurrent users logged in, should ticket booking and generating an "E-Ticket Number" be implemented by a "synchronized" or a "static synchronized" method? Well, are you aware of the difference between a static method and an instance method in general? The only difference that synchronized makes is that before the VM starts running that method, it has to acquire a monitor. For an instance method, the lock acquired is the one associated with the object you're calling the method on. For a static method, the lock acquired is associated

I want to share a variable between multiple threads like this: boolean flag = true; T1 main = new T1(); T2 help = new T2(); main.start(); help.start(); I'd like to share flag between main and help thread where these are two different Java classes I've created. Is any way to do this? Thanks! Brian Agnew Both T1 and T2 can refer to a class containing this variable. You can then make this variable volatile , and this means that Changes to that variable are immediately visible in both threads. See this article for more info. Volatile variables share the visibility features of synchronized but none

This is a general Java question and not an Android one first off! I'd like to know how to run code on the main thread, from the context of a secondary thread. For example: new Thread(new Runnable() { public void run() { //work out pi to 1,000 DP (takes a while!) //print the result on the main thread } }).start(); That sort of thing - I realise my example is a little poor since in Java you don't need to be in the main thread to print something out, and that Swing has an event queue also - but the generic situation where you might need to run say a Runnable on the main thread while in the