yackx · February 3, 2014 12:52 · Feb 3, 2014
diff --git a/philosophers.groovy b/philosophers.groovy
@@ -0,0 +1,59 @@
+#!/usr/bin/env groovy
+
+import static groovyx.gpars.GParsPool.withPool
+
+import groovy.transform.*
+import java.util.concurrent.*
+
+@TypeChecked
+class Philosopher {
+
+    enum State { THINKING, HUNGRY, EATING }
+
+    int MAX_TIME = 1 * 1000
+
+    int id
+    State state
+    Semaphore left, right
+
+    private void doItSomeTime() {
+        sleep(ThreadLocalRandom.current().nextLong(MAX_TIME))
+    }
+
+    private void dine() {
+        state = State.THINKING
+        println this
+        doItSomeTime()
+
+        state = State.HUNGRY
+        println this
+
+        left.acquire()
+        right.acquire()
+
+        state = State.EATING
+        doItSomeTime()
+        println this
+
+        right.release()
+        left.release()
+
+        dine()
+    }
+
+    @Override String toString() {
+        "#${id} is $state"
+    }
+}
+
+int PHILOSOPHER_COUNT = 5
+
+List<Semaphore> forks = (1..PHILOSOPHER_COUNT).collect { new Semaphore(1) }
+
+List<Philosopher> philosophers = (1..PHILOSOPHER_COUNT).collect { i ->
+    new Philosopher(id: i, left: forks[i - 1], right: forks[i % PHILOSOPHER_COUNT])
+}
+
+withPool(PHILOSOPHER_COUNT) {
+    philosophers.eachParallel { it.dine() }
+}