added ArangoCollection.drop(isSystem)

Author: Mark

src/main/java/com/arangodb/ArangoCollectionAsync.java

@@ -651,7 +651,21 @@ public CompletableFuture<CollectionPropertiesEntity> count() {
 	 * @return void
 	 */
 	public CompletableFuture<Void> drop() {
-		return executor.execute(dropRequest(), Void.class);
+		return executor.execute(dropRequest(null), Void.class);
+	}
+
+	/**
+	 * Drops the collection
+	 * 
+	 * @see <a href="https://docs.arangodb.com/current/HTTP/Collection/Creating.html#drops-collection">API
+	 *      Documentation</a>
+	 * @param isSystem
+	 *            Whether or not the collection to drop is a system collection. This parameter must be set to true in
+	 *            order to drop a system collection.
+	 * @return void
+	 */
+	public CompletableFuture<Void> drop(final boolean isSystem) {
+		return executor.execute(dropRequest(isSystem), Void.class);
 	}
 
 	/**

src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -107,6 +107,35 @@ public void deleteCollection() throws InterruptedException, ExecutionException {
 		}
 	}
 
+	@Test
+	public void deleteSystemCollection() throws InterruptedException, ExecutionException {
+		final String name = "_system_test";
+		db.createCollection(name, new CollectionCreateOptions().isSystem(true)).get();
+		db.collection(name).drop(true).get();
+		try {
+			db.collection(name).getInfo().get();
+			fail();
+		} catch (final ArangoDBException e) {
+		}
+	}
+
+	@Test
+	public void deleteSystemCollectionFail() throws InterruptedException, ExecutionException {
+		final String name = "_system_test";
+		db.createCollection(name, new CollectionCreateOptions().isSystem(true)).get();
+		try {
+			db.collection(name).drop().get();
+			fail();
+		} catch (final ArangoDBException e) {
+		}
+		db.collection(name).drop(true).get();
+		try {
+			db.collection(name).getInfo().get();
+			fail();
+		} catch (final ArangoDBException e) {
+		}
+	}
+
 	@Test
 	public void getIndex() throws InterruptedException, ExecutionException {
 		try {