ONOS-1470 Implemented component config REST API.

Change-Id: I637456a1dfd364ff3184cded8a5e8b251afc9987
diff --git a/web/api/src/main/java/org/onosproject/rest/ComponentConfigWebResource.java b/web/api/src/main/java/org/onosproject/rest/ComponentConfigWebResource.java
new file mode 100644
index 0000000..07fe8a1
--- /dev/null
+++ b/web/api/src/main/java/org/onosproject/rest/ComponentConfigWebResource.java
@@ -0,0 +1,85 @@
+/*
+ * 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.rest;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cfg.ConfigProperty;
+
+import javax.ws.rs.DELETE;
+import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.core.Response;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Set;
+
+/**
+ * REST resource for cluster-wide component configuration.
+ */
+@Path("configuration")
+public class ComponentConfigWebResource extends AbstractWebResource {
+
+    @GET
+    public Response getComponentConfigs() {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        Set<String> components = service.getComponentNames();
+        ObjectNode root = mapper().createObjectNode();
+        components.forEach(c -> encodeConfigs(c, service.getProperties(c), root));
+        return ok(root).build();
+    }
+
+    @GET
+    @Path("{component}")
+    public Response getComponentConfigs(@PathParam("component") String component) {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        ObjectNode root = mapper().createObjectNode();
+        encodeConfigs(component, nullIsNotFound(service.getProperties(component),
+                                                "No such component"), root);
+        return ok(root).build();
+    }
+
+    // Encodes the specified properties as an object in the given node.
+    private void encodeConfigs(String component, Set<ConfigProperty> props,
+                               ObjectNode node) {
+        ObjectNode compNode = mapper().createObjectNode();
+        node.set(component, compNode);
+        props.forEach(p -> compNode.put(p.name(), p.value()));
+    }
+
+    @POST
+    @Path("{component}")
+    public Response setComponentConfigs(@PathParam("component") String component,
+                                        InputStream request) throws IOException {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        ObjectNode props = (ObjectNode) mapper().readTree(request);
+        props.fieldNames().forEachRemaining(k -> service.setProperty(component, k,
+                                                                     props.path(k).asText()));
+        return Response.noContent().build();
+    }
+
+    @DELETE
+    @Path("{component}")
+    public Response unsetComponentConfigs(@PathParam("component") String component,
+                                          InputStream request) throws IOException {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        ObjectNode props = (ObjectNode) mapper().readTree(request);
+        props.fieldNames().forEachRemaining(k -> service.unsetProperty(component, k));
+        return Response.noContent().build();
+    }
+}
diff --git a/web/api/src/main/java/org/onosproject/rest/exceptions/BadRequestMapper.java b/web/api/src/main/java/org/onosproject/rest/exceptions/BadRequestMapper.java
new file mode 100644
index 0000000..fcef3b1
--- /dev/null
+++ b/web/api/src/main/java/org/onosproject/rest/exceptions/BadRequestMapper.java
@@ -0,0 +1,29 @@
+/*
+ * 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.rest.exceptions;
+
+import javax.ws.rs.core.Response;
+import java.io.IOException;
+
+/**
+ * Mapper for IO exceptions to the BAD_REQUEST response code.
+ */
+public class BadRequestMapper extends AbstractMapper<IOException> {
+    @Override
+    protected Response.Status responseStatus() {
+        return Response.Status.BAD_REQUEST;
+    }
+}
diff --git a/web/api/src/main/webapp/WEB-INF/web.xml b/web/api/src/main/webapp/WEB-INF/web.xml
index 7741afa..ba7e65f 100644
--- a/web/api/src/main/webapp/WEB-INF/web.xml
+++ b/web/api/src/main/webapp/WEB-INF/web.xml
@@ -59,9 +59,11 @@
                 org.onosproject.rest.exceptions.ServiceNotFoundMapper,
                 org.onosproject.rest.exceptions.NotFoundMapper,
                 org.onosproject.rest.exceptions.ServerErrorMapper,
+                org.onosproject.rest.exceptions.BadRequestMapper,
                 org.onosproject.rest.JsonBodyWriter,
 
                 org.onosproject.rest.ApplicationsWebResource,
+                org.onosproject.rest.ComponentConfigWebResource,
                 org.onosproject.rest.ClusterWebResource,
                 org.onosproject.rest.DevicesWebResource,
                 org.onosproject.rest.LinksWebResource,