added FlowObjectiveService to act as an objective manager between applications and drivers

Change-Id: I4dc44db8bafae8a55b7663895c87b1b08645637f
diff --git a/core/net/src/main/java/org/onosproject/net/driver/impl/DriverManager.java b/core/net/src/main/java/org/onosproject/net/driver/impl/DriverManager.java
new file mode 100644
index 0000000..dc9c6aa
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/driver/impl/DriverManager.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright 2015 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.driver.impl;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.driver.Behaviour;
+import org.onosproject.net.driver.DefaultDriverData;
+import org.onosproject.net.driver.DefaultDriverHandler;
+import org.onosproject.net.driver.Driver;
+import org.onosproject.net.driver.DriverAdminService;
+import org.onosproject.net.driver.DriverData;
+import org.onosproject.net.driver.DriverHandler;
+import org.onosproject.net.driver.DriverProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Map;
+import java.util.Set;
+
+
+@Component(immediate = true)
+@Service
+public class DriverManager implements DriverAdminService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private Set<DriverProvider> providers = Sets.newConcurrentHashSet();
+    private Map<String, Driver> driverByName = Maps.newConcurrentMap();
+    private Map<String, Driver> driverByKey = Maps.newConcurrentMap();
+
+    @Activate
+    protected void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        log.info("Stopped");
+    }
+
+
+    @Override
+    public Set<DriverProvider> getProviders() {
+        return ImmutableSet.copyOf(providers);
+    }
+
+    @Override
+    public void registerProvider(DriverProvider provider) {
+        provider.getDrivers().forEach(driver -> {
+            driverByName.put(driver.name(), driver);
+            driverByKey.put(key(driver.manufacturer(),
+                                driver.hwVersion(),
+                                driver.swVersion()), driver);
+        });
+        providers.add(provider);
+    }
+
+    @Override
+    public void unregisterProvider(DriverProvider provider) {
+        provider.getDrivers().forEach(driver -> {
+            driverByName.remove(driver.name());
+            driverByKey.remove(key(driver.manufacturer(),
+                                   driver.hwVersion(),
+                                   driver.swVersion()));
+        });
+        providers.remove(provider);
+    }
+
+    @Override
+    public Set<Driver> getDrivers(Class<? extends Behaviour>... withBehaviours) {
+        //TODO
+        return null;
+    }
+
+    @Override
+    public Driver getDriver(String driverName) {
+        //TODO: replace with fallback driver.
+        return driverByName.getOrDefault(driverName, driverByName.get("default"));
+    }
+
+    @Override
+    public Driver getDriver(String mfr, String hw, String sw) {
+        return driverByKey.getOrDefault(key(mfr, hw, sw), driverByName.get("default"));
+    }
+
+    @Override
+    public DriverHandler createHandler(String driverName, DeviceId deviceId, String... credentials) {
+        Driver driver = driverByName.get(driverName);
+        return new DefaultDriverHandler(new DefaultDriverData(driver));
+    }
+
+    @Override
+    public DriverHandler createHandler(DriverData data, DeviceId deviceId, String... credentials) {
+        return null;
+    }
+
+    private String key(String mfr, String hw, String sw) {
+        return String.format("%s-%s-%s", mfr, hw, sw);
+    }
+
+}