feat: fix CachedEnforcer bug that false result was not cached (#457)

Author: raiki02

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

@@ -133,8 +133,8 @@ public boolean enforce(Object... rvals) {
             return super.enforce(rvals);
         }
 
-        boolean cachedResult = getCachedResult(key);
-        if (cachedResult) {
+        Boolean cachedResult = getCachedResult(key);
+        if (cachedResult != null) {
             return cachedResult;
         }
 
@@ -217,7 +217,7 @@ public boolean removePolicies(String[][] rules) {
      * @param key The cache key.
      * @return The cached result, or null if not found.
      */
-    private boolean getCachedResult(String key) {
+    private Boolean getCachedResult(String key) {
         READ_WRITE_LOCK.readLock().lock();
         try {
             return cache.get(key);

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

@@ -132,7 +132,7 @@ public boolean enforce(Object... rvals) {
         }
 
         Boolean cachedResult = getCachedResult(key);
-        if (cachedResult) {
+        if (cachedResult != null) {
             return cachedResult;
         }
 

src/main/java/org/casbin/jcasbin/persist/cache/Cache.java

@@ -36,7 +36,7 @@ public interface Cache {
      * @param key the key to retrieve
      * @return an Optional containing the boolean value if present, otherwise Optional.empty()
      */
-    boolean get(String key);
+    Boolean get(String key);
 
     /**
      * Delete removes the specific key from the cache.

src/main/java/org/casbin/jcasbin/persist/cache/DefaultCache.java

@@ -79,14 +79,14 @@ public boolean set(String key, boolean value, Object... extra) {
      * @throws CasbinCacheException If the key does not exist in the cache.
      * @return The value corresponding to the key.
      */
-    public boolean get(String key) {
+    public Boolean get(String key) {
         CacheItem item = cache.get(key);
         if (item == null) {
-            return false;
+            return null;
         }
         if (item.isExpired()) {
             cache.remove(key);
-            return false;
+            return null;
         }
         return item.getValue();
     }

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

@@ -29,7 +29,7 @@ public class CachedEnforcerUnitTest {
     private Cache cache;
 
     private void testEnforceCache(String sub, String obj, String act, boolean expectedRes) throws Exception {
-        boolean actualRes = cachedEnforcer.enforce(sub, obj, act);
+        Boolean actualRes = cachedEnforcer.enforce(sub, obj, act);
         assertEquals(String.format("%s, %s, %s: %s, supposed to be %s", sub, obj, act, actualRes, expectedRes), expectedRes, actualRes);
     }
 
@@ -87,17 +87,17 @@ public void testCache() throws Exception {
     public void testInvalidateCache() throws Exception {
         cachedEnforcer = new CachedEnforcer("examples/basic_model.conf", "examples/basic_policy.csv", false);
 
-        boolean cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
-        assertFalse(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, false), cacheKey);
+        Boolean cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
+        assertNull(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, null), cacheKey);
 
-        boolean actualRes = cachedEnforcer.enforce("alice", "data1", "read");
+        Boolean actualRes = cachedEnforcer.enforce("alice", "data1", "read");
         cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
         assertTrue(String.format("alice, data1, read: %s, supposed to be %s", actualRes, true), actualRes);
         assertTrue(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, true), cacheKey);
 
         cachedEnforcer.invalidateCache();
         cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
-        assertFalse(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, false), cacheKey);
+        assertNull(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, null), cacheKey);
 
     }
 
@@ -132,14 +132,14 @@ public void testCacheExpiration() throws Exception {
         // Test cache expiration
         cache.set(getKey("alice", "data1", "read"),true,Duration.ofMillis(10));
         cachedEnforcer.setCache(cache);
-        boolean cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
+        Boolean cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
         assertTrue(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, true), cacheKey);
 
         // Wait for the cache to expire
         Thread.sleep(15);
 
         cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("alice", "data1", "read"));
-        assertFalse(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, false), cacheKey);
+        assertNull(String.format("alice, data1, read: %s, supposed to be %s", cacheKey, null), cacheKey);
 
         // Replace cache during test run
         cache.clear();
@@ -152,7 +152,7 @@ public void testCacheExpiration() throws Exception {
         cache.set(getKey("jack", "data1", "write"),true,Duration.ofMillis(1000));
         cachedEnforcer.setCache(cache);
         cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("bob", "data1", "read"));
-        assertFalse(String.format("bob, data1, read: %s, supposed to be %s", cacheKey, false), cacheKey);
+        assertNull(String.format("bob, data1, read: %s, supposed to be %s", cacheKey, null), cacheKey);
 
         cacheKey = cachedEnforcer.getCache().get(cachedEnforcer.getCacheKey("jack", "data1", "write"));
         assertTrue(String.format("jack, data1, write: %s, supposed to be %s", cacheKey, true), cacheKey);