FIXME: Move to app package

Change-Id: Iac84243d5b4767109d3c375efa36fd67bf9892d0
diff --git a/core/api/src/main/java/org/onosproject/app/ApplicationIdStore.java b/core/api/src/main/java/org/onosproject/app/ApplicationIdStore.java
new file mode 100644
index 0000000..15595dd
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/app/ApplicationIdStore.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2014-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.app;
+
+import org.onosproject.core.ApplicationId;
+
+import java.util.Set;
+
+/**
+ * Manages application IDs.
+ */
+public interface ApplicationIdStore {
+
+    /**
+     * Returns the set of currently registered application identifiers.
+     *
+     * @return set of application ids
+     */
+    Set<ApplicationId> getAppIds();
+
+    /**
+     * Returns an existing application id from a given id.
+     *
+     * @param id the short value of the id
+     * @return an application id; null if no such app registered
+     */
+    ApplicationId getAppId(Short id);
+
+    /**
+     * Returns registered application id from the given name.
+     *
+     * @param name application name
+     * @return an application id; null if no such app registered
+     */
+    ApplicationId getAppId(String name);
+
+    /**
+     * Registers a new application by its name, which is expected
+     * to follow the reverse DNS convention, e.g.
+     * {@code org.flying.circus.app}
+     *
+     * @param identifier string identifier
+     * @return the application id
+     */
+    ApplicationId registerApplication(String identifier);
+}