Polling link provider

    The provider is capable of polling the environment using the
    device driver behaviour (LinkDiscovery)

Change-Id: Ia09f866299d38c4de9b13201c9cf63b03909164a

+/*
+ * Copyright 2016-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.behaviour;
+
+import org.onosproject.net.driver.HandlerBehaviour;
+import org.onosproject.net.link.LinkDescription;
+
+import java.util.Set;
+
+/**
+ * A HandlerBehaviour to discover links.
+ */
+public interface LinkDiscovery extends HandlerBehaviour {
+
+
+    /**
+     * Returns set of discovered {@link LinkDescription}.
+     * @return set of LinkDescription.
+     */
+    Set<LinkDescription> getLinks();
+}
\ No newline at end of file

+COMPILE_DEPS = [
+    '//lib:CORE_DEPS',
+]
+
+TEST_DEPS = [
+    '//lib:TEST_ADAPTERS',
+    '//utils/osgi:onlab-osgi-tests',
+]
+
+osgi_jar_with_tests (
+    deps = COMPILE_DEPS,
+    test_deps = TEST_DEPS,
+)
+
+onos_app (
+  app_name = 'org.onosproject.linkdiscovery',
+  title = 'Link Discovery Provider',
+  category = 'Provider',
+  url = 'http://onosproject.org',
+  description = 'ONOS link discovery provider.',
+)
\ No newline at end of file

+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+  ~ Copyright 2016-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.
+  -->
+<app name="org.onosproject.linkdiscovery" origin="acino.eu" version="${project.version}"
+     category="Provider" url="http://onosproject.org" title="ONOS link discovery provider"
+     featuresRepo="mvn:${project.groupId}/${project.artifactId}/${project.version}/xml/features"
+     features="${project.artifactId}">
+    <description>${project.description}</description>
+    <artifact>mvn:${project.groupId}/onos-linkdiscovery-provider/${project.version}</artifact>
+</app>

+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+
+<!--
+  ~ Copyright 2016-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.
+  --><features xmlns="http://karaf.apache.org/xmlns/features/v1.2.0" name="${project.artifactId}-${project.version}">
+    <feature name="${project.artifactId}" version="${project.version}"
+             description="${project.description}">
+        <feature>onos-api</feature>
+        <bundle>mvn:${project.groupId}/onos-linkdiscovery-provider/${project.version}</bundle>
+    </feature>
+</features>
+

+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2016-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.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.onosproject</groupId>
+        <artifactId>onos-providers</artifactId>
+        <version>1.7.0-SNAPSHOT</version>
+    </parent>
+
+
+    <artifactId>onos-linkdiscovery-provider</artifactId>
+    <packaging>bundle</packaging>
+
+    <properties>
+        <onos.app.name>org.onosproject.linkdiscovery</onos.app.name>
+        <onos.app.title>Link Discovery Provider</onos.app.title>
+        <onos.app.origin>acino.eu</onos.app.origin>
+        <onos.app.category>Provider</onos.app.category>
+        <onos.app.readme>ONOS link discovery provider.</onos.app.readme>
+    </properties>
+
+    <description>ONOS link discovery provider</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.osgi</groupId>
+            <artifactId>org.osgi.compendium</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-osgi</artifactId>
+            <version>${project.version}</version>
+            <classifier>tests</classifier>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.easymock</groupId>
+            <artifactId>easymock</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-api</artifactId>
+            <classifier>tests</classifier>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>
\ No newline at end of file

+/*
+ * Copyright 2016-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.
+ */
+
+/**
+ * Provider that uses LinkDiscovery {@link org.onosproject.net.behaviour.LinkDiscovery}
+ * to poll the network environment as a means of link discovery.
+ */
+package org.onosproject.provider.linkdiscovery.impl;
\ No newline at end of file

+/*
+ * Copyright 2016-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.
+ */
+
+/**
+ * Test package for the Link Discovery Provider.
+ */
+package org.onosproject.provider.linkdiscovery.impl;
\ No newline at end of file

@@ -49,6 +49,7 @@
         <module>isis</module>
         <module>lisp</module>
         <module>ospf</module>
+        <module>link</module>
     </modules>
 
     <dependencies>