Improving jax-rs APIS of CDM-F

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/beans/ActivityList.java

@@ -0,0 +1,108 @@
+/*
+ *   Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ *   WSO2 Inc. licenses this file to you 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.wso2.carbon.device.mgt.jaxrs.beans;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import io.swagger.annotations.ApiModel;
+import io.swagger.annotations.ApiModelProperty;
+import org.wso2.carbon.device.mgt.common.Device;
+import org.wso2.carbon.device.mgt.common.operation.mgt.Activity;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@ApiModel(value = "List of activities", description = "This contains a set of activities that matches a given " +
+        "criteria as a collection")
+public class ActivityList {
+
+    private int count;
+    private String next;
+    private String previous;
+
+    private List<Activity> activities = new ArrayList<>();
+
+    /**
+     * Number of Devices returned.
+     */
+    @ApiModelProperty(value = "Number of activities returned.")
+    @JsonProperty("count")
+    public int getCount() {
+        return count;
+    }
+
+    public void setCount(int count) {
+        this.count = count;
+    }
+
+
+    /**
+     * Link to the next subset of resources qualified. \nEmpty if no more resources are to be returned.
+     */
+    @ApiModelProperty(value = "Link to the next subset of resources qualified. \n " +
+            "Empty if no more resources are to be returned.")
+    @JsonProperty("next")
+    public String getNext() {
+        return next;
+    }
+
+    public void setNext(String next) {
+        this.next = next;
+    }
+
+    /**
+     * Link to the previous subset of resources qualified. \nEmpty if current subset is the first subset returned.
+     */
+    @ApiModelProperty(value = "Link to the previous subset of resources qualified. \n" +
+            "Empty if current subset is the first subset returned.")
+    @JsonProperty("previous")
+    public String getPrevious() {
+        return previous;
+    }
+
+    public void setPrevious(String previous) {
+        this.previous = previous;
+    }
+
+    /**
+     **/
+    @ApiModelProperty(value = "List of devices returned")
+    @JsonProperty("activities")
+    public List<Activity> getList() {
+        return activities;
+    }
+
+    public void setList(List<Activity> activities) {
+        this.activities = activities;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("{\n");
+
+        sb.append("  count: ").append(count).append(",\n");
+        sb.append("  next: ").append(next).append(",\n");
+        sb.append("  previous: ").append(previous).append(",\n");
+        sb.append("  devices: [").append(activities).append("\n");
+        sb.append("]}\n");
+        return sb.toString();
+    }
+
+
+}

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/ActivityInfoProviderService.java

@@ -22,6 +22,8 @@ import io.swagger.annotations.*;
 import org.wso2.carbon.apimgt.annotations.api.API;
 import org.wso2.carbon.apimgt.annotations.api.Permission;
 import org.wso2.carbon.device.mgt.common.operation.mgt.Activity;
+import org.wso2.carbon.device.mgt.jaxrs.beans.ActivityList;
+import org.wso2.carbon.device.mgt.jaxrs.beans.ErrorResponse;
 
 import javax.ws.rs.*;
 import javax.ws.rs.core.MediaType;
@@ -44,7 +46,6 @@ public interface ActivityInfoProviderService {
     @ApiOperation(
             produces = MediaType.APPLICATION_JSON,
             httpMethod = "GET",
-            response = Activity.class,
             value = "Retrieve details of a particular activity.",
             notes = "This will return information of a particular activity i.e. meta information of an operation, " +
                     "etc; including the responses from the devices.",
@@ -71,12 +72,20 @@ public interface ActivityInfoProviderService {
                     code = 304,
                     message = "Not Modified. \n Empty body because the client has already the latest version of " +
                             "the requested resource."),
+            @ApiResponse(
+                    code = 400,
+                    message = "Bad Request. \n Invalid request or validation error.",
+                    response = ErrorResponse.class),
+            @ApiResponse(
+                    code = 404,
+                    message = "Not Found. \n No activity is found under the provided id."),
             @ApiResponse(
                     code = 406,
                     message = "Not Acceptable.\n The requested media type is not supported"),
             @ApiResponse(
                     code = 500,
-                    message = "Internal Server ErrorResponse. \n Server error occurred while fetching activity data.")
+                    message = "Internal Server ErrorResponse. \n Server error occurred while fetching activity data.",
+                    response = ErrorResponse.class)
     })
     @Permission(scope = "activity-view", permissions = {"/permission/admin/device-mgt/admin/activities/view"})
     Response getActivity(
@@ -96,8 +105,6 @@ public interface ActivityInfoProviderService {
     @ApiOperation(
             produces = MediaType.APPLICATION_JSON,
             httpMethod = "GET",
-            response = Activity.class,
-            responseContainer = "List",
             value = "Retrieve details of a particular activity.",
             notes = "This will return information of a particular activities i.e. meta information of operations, " +
                     "etc; including the responses from the devices which happened after given time.",
@@ -106,8 +113,7 @@ public interface ActivityInfoProviderService {
             @ApiResponse(
                     code = 200,
                     message = "OK. \n Activity details are successfully fetched",
-                    response = Activity.class,
+                    response = ActivityList.class,
-                    responseContainer = "List",
                     responseHeaders = {
                             @ResponseHeader(
                                     name = "Content-Type",
@@ -130,7 +136,8 @@ public interface ActivityInfoProviderService {
                     message = "Not Acceptable.\n The requested media type is not supported"),
             @ApiResponse(
                     code = 500,
-                    message = "Internal Server ErrorResponse. \n Server error occurred while fetching activity data.")
+                    message = "Internal Server ErrorResponse. \n Server error occurred while fetching activity data.",
+                    response = ErrorResponse.class)
     })
     @Permission(scope = "activity-view", permissions = {"/permission/admin/device-mgt/admin/activities/view"})
     Response getActivities(
@@ -138,8 +145,8 @@ public interface ActivityInfoProviderService {
                     name = "timestamp",
                     value = "Validates if the requested variant has not been modified since the time specified, this " +
                             "should be provided in unix format in seconds.",
-                    required = false)
+                    required = true)
-            @QueryParam("timestamp") String timestamp,
+            @QueryParam("timestamp") long timestamp,
             @ApiParam(
                     name = "If-Modified-Since",
                     value = "Validates if the requested variant has not been modified since the time specified",

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/admin/ApplicationManagementAdminService.java

@@ -31,7 +31,7 @@ import javax.ws.rs.core.Response;
 
 @API(name = "Application", version = "1.0.0", context = "/devicemgt_admin/applications", tags = {"devicemgt_admin"})
 
-@Path("/applications")
+@Path("/admin/applications")
 @Api(value = "Application Management Administrative Service", description = "This an  API intended to be used by " +
         "'internal' components to log in as an admin user and do a selected number of operations. " +
         "Further, this is strictly restricted to admin users only ")

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/admin/DeviceManagementAdminService.java

@@ -28,7 +28,7 @@ import javax.ws.rs.core.Response;
 
 @API(name = "DeviceManagementAdmin", version = "1.0.0", context = "/devicemgt_admin/applications",
         tags = {"devicemgt_admin"})
-@Path("/devices")
+@Path("/admin/devices")
 @Api(value = "Device Management Administrative Service", description = "This an  API intended to be used by " +
         "'internal' components to log in as an admin user and do a selected number of operations. " +
         "Further, this is strictly restricted to admin users only ")

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/admin/GroupManagementAdminService.java

@@ -27,7 +27,7 @@ import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 import java.util.Date;
 
-@Path("/groups")
+@Path("/admin/groups")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 @Api(value = "Group Management Administrative Service", description = "This an  API intended to be used by " +

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/admin/UserManagementAdminService.java

@@ -26,7 +26,7 @@ import javax.ws.rs.*;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 
-@Path("/users")
+@Path("/admin/users")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 @Api(value = "User Management Administrative Service", description = "This an  API intended to be used by " +

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/ActivityProviderServiceImpl.java

@@ -23,7 +23,10 @@ import org.apache.commons.logging.LogFactory;
 import org.wso2.carbon.device.mgt.common.operation.mgt.Activity;
 import org.wso2.carbon.device.mgt.common.operation.mgt.OperationManagementException;
 import org.wso2.carbon.device.mgt.core.service.DeviceManagementProviderService;
+import org.wso2.carbon.device.mgt.jaxrs.beans.ErrorResponse;
 import org.wso2.carbon.device.mgt.jaxrs.service.api.ActivityInfoProviderService;
+import org.wso2.carbon.device.mgt.jaxrs.service.impl.util.RequestValidationUtil;
+import org.wso2.carbon.device.mgt.jaxrs.service.impl.util.UnexpectedServerErrorException;
 import org.wso2.carbon.device.mgt.jaxrs.util.DeviceMgtAPIUtils;
 
 import javax.ws.rs.*;
@@ -44,23 +47,30 @@ public class ActivityProviderServiceImpl implements ActivityInfoProviderService
     public Response getActivity(
             @PathParam("id") String id,
             @HeaderParam("If-Modified-Since") String ifModifiedSince) {
-        Activity operation = null;
+        Activity activity;
         DeviceManagementProviderService dmService;
         try {
+            RequestValidationUtil.validateActivityId(id);
+
             dmService = DeviceMgtAPIUtils.getDeviceManagementService();
-            operation = dmService.getOperationByActivityId(id);
+            activity = dmService.getOperationByActivityId(id);
+            if (activity == null) {
+                return Response.status(Response.Status.NOT_FOUND).entity("No activity can be found upon the provided " +
+                        "activity id '" + id + "'").build();
+            }
         } catch (OperationManagementException e) {
             String msg = "ErrorResponse occurred while fetching the activity for the supplied id.";
             log.error(msg, e);
-            Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+            throw new UnexpectedServerErrorException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
         }
-        return Response.status(Response.Status.OK).entity(operation).build();
+        return Response.status(Response.Status.OK).entity(activity).build();
     }
 
     @GET
     @Override
     public Response getActivities(
-            @QueryParam("timestamp") String timestamp,
+            @QueryParam("timestamp") long timestamp,
             @HeaderParam("If-Modified-Since") String ifModifiedSince,
             @QueryParam("offset") int offset,
             @QueryParam("limit") int limit) {
@@ -68,11 +78,13 @@ public class ActivityProviderServiceImpl implements ActivityInfoProviderService
         DeviceManagementProviderService dmService;
         try {
             dmService = DeviceMgtAPIUtils.getDeviceManagementService();
-            activities = dmService.getActivitiesUpdatedAfter(Long.parseLong(timestamp));
+            activities = dmService.getActivitiesUpdatedAfter(timestamp);
+
         } catch (OperationManagementException e) {
             String msg = "ErrorResponse occurred while fetching the activities updated after given time stamp.";
             log.error(msg, e);
-            Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+            throw new UnexpectedServerErrorException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
         }
         return Response.status(Response.Status.OK).entity(activities).build();
     }

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/admin/ApplicationManagementAdminServiceImpl.java

@@ -40,7 +40,7 @@ import javax.ws.rs.Produces;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 
-@Path("/applications")
+@Path("/admin/applications")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 public class ApplicationManagementAdminServiceImpl implements ApplicationManagementAdminService {

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/admin/DeviceManagementAdminServiceImpl.java

@@ -30,7 +30,7 @@ import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 import java.util.List;
 
-@Path("/devices")
+@Path("/admin/devices")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 public class DeviceManagementAdminServiceImpl implements DeviceManagementAdminService {

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/admin/GroupManagementAdminServiceImpl.java

@@ -31,7 +31,7 @@ import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 import java.util.Date;
 
-@Path("/groups")
+@Path("/admin/groups")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 public class GroupManagementAdminServiceImpl implements GroupManagementAdminService {

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/admin/UserManagementAdminServiceImpl.java

@@ -26,7 +26,7 @@ import javax.ws.rs.*;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 
-@Path("/users")
+@Path("/admin/users")
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 public class UserManagementAdminServiceImpl implements UserManagementAdminService {

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/util/RequestValidationUtil.java

@@ -168,4 +168,43 @@ public class RequestValidationUtil {
                             "cannot be null").build());
         }
     }
+
+    public static void validateTimestamp(String timestamp) {
+        if (timestamp == null || timestamp.isEmpty()) {
+            throw new InputValidationException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage("Timestamp value " +
+                            "cannot be null or empty").build());
+        }
+        try {
+            Long.parseLong(timestamp);
+        } catch (NumberFormatException e) {
+            throw new InputValidationException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage(
+                            "Invalid timestamp value").build());
+        }
+    }
+
+    public static void validateActivityId(String activityId) {
+        if (activityId == null || activityId.isEmpty()) {
+            throw new InputValidationException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage("Activity Id " +
+                            "cannot be null or empty. It should be in the form of " +
+                            "'[ACTIVITY][_][any-positive-integer]' instead").build());
+        }
+        String[] splits = activityId.split("_");
+        if (splits == null || splits[0] == null || splits[0].isEmpty() || !"ACTIVITY".equals(splits[0]) ||
+                splits[1] == null || splits[0].isEmpty()) {
+            throw new InputValidationException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage(
+                            "Activity Id should be in the form of '[ACTIVITY][_][any-positive-integer]'").build());
+        }
+        try {
+            Long.parseLong(splits[1]);
+        } catch (NumberFormatException e) {
+            throw new InputValidationException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(400l).setMessage(
+                            "Activity Id should be in the form of '[ACTIVITY][_][any-positive-integer]'").build());
+        }
+    }
+
 }

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/util/UnexpectedServerErrorException.java

@@ -0,0 +1,34 @@
+/*
+ *   Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ *   WSO2 Inc. licenses this file to you 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.wso2.carbon.device.mgt.jaxrs.service.impl.util;
+
+import org.wso2.carbon.device.mgt.jaxrs.beans.ErrorResponse;
+
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.Response;
+
+public class UnexpectedServerErrorException extends WebApplicationException {
+
+    private static final long serialVersionUID = 147943579458906890L;
+
+    public UnexpectedServerErrorException(ErrorResponse error) {
+        super(Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(error).build());
+    }
+
+}

components/device-mgt/org.wso2.carbon.device.mgt.common/src/main/java/org/wso2/carbon/device/mgt/common/operation/mgt/Activity.java

@@ -19,6 +19,7 @@
 
 package org.wso2.carbon.device.mgt.common.operation.mgt;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import io.swagger.annotations.ApiModel;
 import io.swagger.annotations.ApiModelProperty;
 
@@ -36,27 +37,36 @@ public class Activity {
             name = "activityId",
             value = "Activity identifier",
             required = true)
+    @JsonProperty("activityId")
     private String activityId;
+
     @ApiModelProperty(
             name = "code",
             value = "Activity code",
             required = true)
+    @JsonProperty("code")
     private String code;
+
     @ApiModelProperty(
             name = "type",
             value = "Activity type",
             required = true,
             allowableValues = "CONFIG, MESSAGE, INFO, COMMAND, PROFILE, POLICY")
+    @JsonProperty("type")
     private Type type;
+
     @ApiModelProperty(
             name = "createdTimeStamp",
             value = "Timestamp recorded when the activity took place",
             required = true)
+    @JsonProperty("createdTimestamp")
     private String createdTimeStamp;
+
     @ApiModelProperty(
             name = "activityStatuses",
             value = "Collection of statuses corresponding to the activity",
             required = true)
+    @JsonProperty("activityStatuses")
     private List<ActivityStatus> activityStatus;
 
     public String getActivityId() {

components/device-mgt/org.wso2.carbon.device.mgt.common/src/main/java/org/wso2/carbon/device/mgt/common/operation/mgt/ActivityStatus.java

@@ -19,6 +19,7 @@
 
 package org.wso2.carbon.device.mgt.common.operation.mgt;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import io.swagger.annotations.ApiModel;
 import io.swagger.annotations.ApiModelProperty;
 import org.wso2.carbon.device.mgt.common.DeviceIdentifier;
@@ -31,25 +32,33 @@ public class ActivityStatus {
     public enum Status {
         IN_PROGRESS, PENDING, COMPLETED, ERROR, REPEATED
     }
+
     @ApiModelProperty(
             name = "deviceIdentifier",
             value = "Device identifier of the device.",
             required = true)
+    @JsonProperty("deviceIdentifier")
     private DeviceIdentifier deviceIdentifier;
+
     @ApiModelProperty(
             name = "status",
             value = "Status of the activity performed.",
             required = true)
+    @JsonProperty("status")
     private Status status;
+
     @ApiModelProperty(
             name = "responses",
             value = "Responses received from devices.",
             required = true)
+    @JsonProperty("responses")
     private List<OperationResponse> responses;
+
     @ApiModelProperty(
             name = "updatedTimestamp    ",
             value = "Last updated time of the activity.",
             required = true)
+    @JsonProperty("updatedTimestamp")
     private String updatedTimestamp;
 
     public DeviceIdentifier getDeviceIdentifier() {

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/operation/mgt/OperationManagerImpl.java

@@ -763,7 +763,7 @@ public class OperationManagerImpl implements OperationManager {
         try {
             OperationManagementDAOFactory.openConnection();
             Activity act = operationDAO.getActivity(operationId);
-            act.setActivityId(activity);
+//            act.setActivityId(activity);
             return act;
         } catch (SQLException e) {
             throw new OperationManagementException("Error occurred while opening a connection to the data source.", e);

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/operation/mgt/dao/impl/GenericOperationDAOImpl.java

@@ -257,7 +257,7 @@ public class GenericOperationDAOImpl implements OperationDAO {
 
         PreparedStatement stmt = null;
         ResultSet rs = null;
-        Activity activity = new Activity();
+        Activity activity = null;
         List<ActivityStatus> activityStatusList = new ArrayList<>();
         try {
             Connection conn = OperationManagementDAOFactory.getConnection();
@@ -281,7 +281,9 @@ public class GenericOperationDAOImpl implements OperationDAO {
 
             int enrolmentId = 0;
             ActivityStatus activityStatus = null;
-            while (rs.next()) {
+
+            if (rs.next()) {
+                activity = new Activity();
                 if (enrolmentId == 0) {
                     activity.setType(Activity.Type.valueOf(rs.getString("OPERATION_TYPE")));
                     activity.setCreatedTimeStamp(new java.util.Date(rs.getLong(("CREATED_TIMESTAMP"))).toString());
@@ -306,6 +308,7 @@ public class GenericOperationDAOImpl implements OperationDAO {
                     activityStatusList.add(activityStatus);
 
                     enrolmentId = rs.getInt("ENROLMENT_ID");
+                    activity.setActivityStatus(activityStatusList);
                 } else {
                     if (rs.getInt("UPDATED_TIMESTAMP") != 0) {
                         activityStatus.getResponses().add(this.getOperationResponse(rs));
@@ -322,7 +325,6 @@ public class GenericOperationDAOImpl implements OperationDAO {
         } finally {
             OperationManagementDAOUtil.cleanupResources(stmt, rs);
         }
-        activity.setActivityStatus(activityStatusList);
         return activity;
     }
 
@@ -523,7 +525,6 @@ public class GenericOperationDAOImpl implements OperationDAO {
     }
 
 
-
     @Override
     public void deleteOperation(int id) throws OperationManagementDAOException {
         PreparedStatement stmt = null;