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GeezerVison is showing github.com — array-stack.java/Main.java at master · moocf/array-stack.java

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import java.util.*;
class Main {
static Deque<Integer> stack;
static ArrayStack<Integer> concurrentStack;
static List<Integer>[] poppedValues;
static int TH = 10, NUM = 1000;
// Each unsafe thread pushes N numbers and pops N, adding
// them to its own poppedValues for checking; using Java's
// sequential stack implementation, ArrayDeque.
static Thread unsafe(int id, int x, int N) {
return new Thread(() -> {
String action = "push";
try {
for (int i=0, y=x; i<N; i++)
stack.push(y++);
Thread.sleep(1000);
action = "pop";
for (int i=0; i<N; i++)
poppedValues[id].add(stack.pop());
}
catch (Exception e) { log(id+": failed "+action); }
});
}
// Each safe thread pushes N numbers and pops N, adding
// them to its own poppedValues for checking; using
// ArrayStack.
static Thread safe(int id, int x, int N) {
return new Thread(() -> {
String action = "push";
try {
for (int i=0, y=x; i<N; i++)
concurrentStack.push(y++);
Thread.sleep(1000);
action = "pop";
for (int i=0; i<N; i++)
poppedValues[id].add(concurrentStack.pop());
}
catch (Exception e) { log(id+": failed "+action);
e.printStackTrace(); }
});
}
// Checks if each thread popped N values, and they are
// globally unique.
static boolean wasLIFO(int N) {
Set<Integer> set = new HashSet<>();
boolean passed = true;
for (int i=0; i<TH; i++) {
int n = poppedValues[i].size();
if (n != N) {
log(i+": popped "+n+"/"+N+" values");
passed = false;
}
for (Integer x : poppedValues[i])
if (set.contains(x)) {
log(i+": has duplicate value "+x);
passed = false;
}
set.addAll(poppedValues[i]);
}
return passed;
}
@SuppressWarnings("unchecked")
static void testThreads(boolean safe) {
stack = new ArrayDeque<>();
concurrentStack = new ArrayStack<>(TH*NUM);
poppedValues = new List[TH];
for (int i=0; i<TH; i++)
poppedValues[i] = new ArrayList<>();
Thread[] threads = new Thread[TH];
for (int i=0; i<TH; i++) {
threads[i] = safe?
safe(i, i*NUM, NUM) :
unsafe(i, i*NUM, NUM);
threads[i].start();
}
try {
for (int i=0; i<TH; i++)
threads[i].join();
}
catch (Exception e) {}
}
public static void main(String[] args) {
log("Starting "+TH+" threads with sequential stack");
testThreads(false);
log("Was LIFO? "+wasLIFO(NUM));
log("");
log("Starting "+TH+" threads with array stack");
testThreads(true);
log("Was LIFO? "+wasLIFO(NUM));
log("");
}
static void log(String x) {
System.out.println(x);
}
}
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