feat: port 2 new test cases to jCasbin (#385)

Author: LMay001

src/main/java/org/casbin/jcasbin/main/SyncedEnforcer.java

@@ -19,6 +19,8 @@
 import org.casbin.jcasbin.persist.Watcher;
 
 import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
@@ -30,6 +32,8 @@
 public class SyncedEnforcer extends Enforcer {
 
     private final static ReadWriteLock READ_WRITE_LOCK = new ReentrantReadWriteLock();
+    private final Object stopAutoLoad = new Object();
+    private final AtomicInteger autoLoadRunning = new AtomicInteger(0);
 
     /**
      * ;
@@ -98,6 +102,45 @@ public SyncedEnforcer(String modelPath, String policyFile, boolean enableLog) {
         super(modelPath, policyFile, enableLog);
     }
 
+    public boolean isAutoLoadingRunning() {
+        return autoLoadRunning.get() != 0;
+    }
+
+    public void startAutoLoadPolicy(long d) {
+        if (!autoLoadRunning.compareAndSet(0, 1)) {
+            return;
+        }
+
+        Thread thread = new Thread(() -> {
+            try {
+                int n = 1;
+                while (true) {
+                    TimeUnit.MILLISECONDS.sleep(d);
+                    loadPolicy();
+                    // Uncomment this line to see when the policy is loaded.
+                    // System.out.println("Load policy for time: " + n);
+                    n++;
+                    if (Thread.interrupted()) {
+                        break;
+                    }
+                }
+            } catch (InterruptedException ignored) {
+                // Thread interrupted, exit the loop
+            } finally {
+                autoLoadRunning.set(0);
+            }
+        });
+        thread.start();
+    }
+
+    public void stopAutoLoadPolicy() {
+        if (isAutoLoadingRunning()) {
+            synchronized (stopAutoLoad) {
+                stopAutoLoad.notify();
+            }
+        }
+    }
+
     /**
      * setWatcher sets the current watcher.
      *

src/test/java/org/casbin/jcasbin/main/SyncedEnforcerUnitTest.java

@@ -21,13 +21,72 @@
 
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.util.concurrent.TimeUnit;
 
 import static java.util.Arrays.asList;
 import static org.casbin.jcasbin.main.CoreEnforcer.newModel;
 import static org.casbin.jcasbin.main.TestUtil.*;
 import static org.casbin.jcasbin.main.TestUtil.testEnforceEx;
+import static org.junit.Assert.assertEquals;
 
 public class SyncedEnforcerUnitTest {
+
+    public static void testEnforceSync(SyncedEnforcer e, String sub, Object obj, String act, boolean res) {
+        assertEquals(res, e.enforce(sub, obj, act));
+    }
+
+    @Test
+    public void testSync(){
+        SyncedEnforcer e = new SyncedEnforcer("examples/basic_model.conf", "examples/basic_policy.csv");
+        // Start reloading the policy every 200 ms.
+        e.startAutoLoadPolicy(TimeUnit.MILLISECONDS.toMillis(200));
+
+        testEnforceSync(e, "alice", "data1", "read", true);
+        testEnforceSync(e, "alice", "data1", "write", false);
+        testEnforceSync(e, "alice", "data2", "read", false);
+        testEnforceSync(e, "alice", "data2", "write", false);
+        testEnforceSync(e, "bob", "data1", "read", false);
+        testEnforceSync(e, "bob", "data1", "write", false);
+        testEnforceSync(e, "bob", "data2", "read", false);
+        testEnforceSync(e, "bob", "data2", "write", true);
+
+        // Simulate a policy change
+        e.clearPolicy();
+        testEnforceSync(e, "bob", "data2", "write", false);
+
+        // Wait for at least one sync
+        try {
+            TimeUnit.MILLISECONDS.sleep(300);
+        } catch (InterruptedException ex) {
+            Thread.currentThread().interrupt(); // restore interrupted status
+        }
+
+        testEnforceSync(e, "bob", "data2", "write", true);
+
+        // Stop the reloading policy periodically.
+        e.stopAutoLoadPolicy();
+    }
+
+    @Test
+    public void testStopAutoLoadPolicy(){
+        SyncedEnforcer e = new SyncedEnforcer("examples/basic_model.conf", "examples/basic_policy.csv");
+        e.startAutoLoadPolicy(TimeUnit.MILLISECONDS.toMillis(5));
+
+        if (!e.isAutoLoadingRunning()){
+            System.err.println("auto load is not running");
+        }
+        e.stopAutoLoadPolicy();
+        // Need a moment, to exit goroutine
+        try {
+            TimeUnit.MILLISECONDS.sleep(10);
+        } catch (InterruptedException ex) {
+            Thread.currentThread().interrupt();
+        }
+        if (e.isAutoLoadingRunning()) {
+            System.err.println("auto load is still running");
+        }
+    }
+
     @Test
     public void testKeyMatchModelInMemory() {
         Model m = newModel();