[ONOS-6348] Intent installer redesign

Change-Id: I9ae2e8158dc1c686eaf848f330566f9dbb78405f
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/InstallerRegistry.java b/core/net/src/main/java/org/onosproject/net/intent/impl/InstallerRegistry.java
new file mode 100644
index 0000000..db5becc
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/InstallerRegistry.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2017-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.net.intent.impl;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+import org.onosproject.net.intent.Intent;
+import org.onosproject.net.intent.IntentInstaller;
+
+import java.util.Map;
+
+/**
+ * The local registry for Intent installer.
+ */
+public class InstallerRegistry {
+    private final Map<Class<? extends Intent>, IntentInstaller<? extends Intent>> installers;
+
+    public InstallerRegistry() {
+        installers = Maps.newConcurrentMap();
+    }
+
+    /**
+     * Registers the specific installer for the given intent class.
+     *
+     * @param cls intent class
+     * @param installer intent installer
+     * @param <T> the type of intent
+     */
+    public <T extends Intent> void registerInstaller(Class<T> cls, IntentInstaller<T> installer) {
+        installers.put(cls, installer);
+    }
+
+    /**
+     * Unregisters the installer for the specific intent class.
+     *
+     * @param cls intent class
+     * @param <T> the type of intent
+     */
+    public <T extends Intent> void unregisterInstaller(Class<T> cls) {
+        installers.remove(cls);
+    }
+
+    /**
+     * Returns immutable set of binding of currently registered intent installers.
+     *
+     * @return the set of installer bindings
+     */
+    public Map<Class<? extends Intent>, IntentInstaller<? extends Intent>> getInstallers() {
+        return ImmutableMap.copyOf(installers);
+    }
+
+    /**
+     * Get an Intent installer by given Intent type.
+     *
+     * @param cls the Intent type
+     * @param <T> the Intent type
+     * @return the Intent installer of the Intent type if exists; null otherwise
+     */
+    public <T extends Intent> IntentInstaller<T> getInstaller(Class<T> cls) {
+        return (IntentInstaller<T>) installers.get(cls);
+    }
+}