HONEYCOMB-360 - Utility for conditional initialization of HC guice modules

Change-Id: Ia1a3f44c7dae0b4b0be99f96abb017e1b022ec32
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>
Signed-off-by: Jan Srnicek <jsrnicek@cisco.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/infra/northbound/common/src/main/java/io/fd/honeycomb/northbound/NorthboundPrivateModule.java b/infra/northbound/common/src/main/java/io/fd/honeycomb/northbound/NorthboundPrivateModule.java
new file mode 100644
index 000000000..da471a06a
--- /dev/null
+++ b/infra/northbound/common/src/main/java/io/fd/honeycomb/northbound/NorthboundPrivateModule.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * 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 io.fd.honeycomb.northbound;
+
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.Module;
+import com.google.inject.PrivateModule;
+
+/**
+ * Base class for Honeycomb's PrivateModules, that are initialized conditionally based on specific configuration.
+ *
+ * @param <T> module configuration type
+ */
+public abstract class NorthboundPrivateModule<T> extends PrivateModule implements ConfigurationSupplier<T> {
+
+    private final Class<T> configClass;
+    private final Module configurationModule;
+    private final Injector injector;
+
+    protected NorthboundPrivateModule(final Module configurationModule, final Class<T> configClass) {
+        this.configurationModule = configurationModule;
+        this.configClass = configClass;
+        this.injector = Guice.createInjector(configurationModule);
+    }
+
+    @Override
+    public final Module getConfigurationModule() {
+        return configurationModule;
+    }
+
+    @Override
+    public final T getConfiguration() {
+        return injector.getInstance(configClass);
+    }
+}