Merge pull request #138 from kevin-canadian/add-list-to-config-cache

Add list() to ConfigCache

owner/src/main/java/org/aeonbits/owner/ConfigCache.java

@@ -8,7 +8,9 @@
 
 package org.aeonbits.owner;
 
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
@@ -115,6 +117,19 @@ public static <T extends Config> T add(Object key, T instance) {
         return (T) CACHE.putIfAbsent(key, instance);
     }
 
+    /**
+     * Lists the key objects for all configuration instances present in the cache.
+     *
+     * @return a set containing the key objects for all instance in the cache.
+     */
+    public static Set<Object> list() {
+        // Create a new Set to ensure that the caller does not modify the contents of our
+        // private map via the result of this call. The key objects themselves are the same
+        // as those contained in the private map, which means that if they are mutable, the
+        // caller will be able to affect the contents of the map (albeit only the keys).
+        return new HashSet<Object>(CACHE.keySet());
+    }
+
     /**
      * Removes all of the cached instances.
      * The cache will be empty after this call returns.

owner/src/test/java/org/aeonbits/owner/cache/CacheConfigTest.java

@@ -17,6 +17,7 @@
 import org.mockito.Matchers;
 
 import java.util.Map;
+import java.util.Set;
 
 import static org.junit.Assert.*;
 import static org.mockito.Matchers.eq;
@@ -60,6 +61,18 @@ public void testGetOrCreateUsingNameKey() {
         assertSame(first, second);
     }
 
+    @Test
+    public void testList() {
+        ConfigCache.getOrCreate("MyConfig1", MyConfig.class);
+        ConfigCache.getOrCreate("MyConfig2", MyConfig.class);
+        ConfigCache.getOrCreate("MyConfig3", MyConfig.class);
+        Set<Object> keys = ConfigCache.list();
+        assertTrue(keys.contains("MyConfig1"));
+        assertTrue(keys.contains("MyConfig2"));
+        assertTrue(keys.contains("MyConfig3"));
+        assertTrue(3 == keys.size());
+    }
+
     @Test
     public void testRemoveUsingClassAsKey() {
         MyConfig first = ConfigCache.getOrCreate(MyConfig.class);