adding apply policy end point

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

@@ -386,5 +386,30 @@ public interface PolicyManagementService {
             @ApiParam(name = "policyIds", value = "Policy ID list to be deactivated.",
                     required = true) List<Integer> policyIds);
 
+    @PUT
+    @Produces("application/json")
+    @Path("apply-changes")
+    @ApiOperation(
+            consumes = MediaType.APPLICATION_JSON,
+            produces = MediaType.APPLICATION_JSON,
+            httpMethod = "PUT",
+            value = "Applying Changes on Policies.",
+            notes = "Policies in the active state will be applied to new device that register with WSO2 EMM based on" +
+                    " the policy enforcement criteria . In a situation where you need to make changes to existing" +
+                    " policies (removing, activating, deactivating and updating) or add new policies, the existing" +
+                    " devices will not receive these changes immediately. Once all the required changes are made" +
+                    " you need to apply the changes to push the policy changes to the existing devices.")
+    @ApiResponses(value = {
+            @ApiResponse(
+                    code = 200,
+                    message = "Changes have been successfully updated."),
+            @ApiResponse(
+                    code = 500,
+                    message = "ErrorResponse in deactivating policies.",
+                    response = ErrorResponse.class)
+    })
+    @Permission(scope = "policy-modify", permissions = {"/permission/admin/device-mgt/admin/policies/update"})
+    Response applyChanges();
+
 
 }

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

@@ -301,4 +301,21 @@ public class PolicyManagementServiceImpl implements PolicyManagementService {
         }
     }
 
+    @Override
+    @PUT
+    @Produces("application/json")
+    @Path("apply-changes")
+    public Response applyChanges() {
+        try {
+            PolicyManagerService policyManagementService = DeviceMgtAPIUtils.getPolicyManagementService();
+            PolicyAdministratorPoint pap = policyManagementService.getPAP();
+            pap.publishChanges();
+        } catch (PolicyManagementException e) {
+            String msg = "Exception in applying changes.";
+            log.error(msg, e);
+            throw new UnexpectedServerErrorException(
+                    new ErrorResponse.ErrorResponseBuilder().setCode(500l).setMessage(msg).build());
+        }
+        return Response.status(Response.Status.OK).entity("Changes have been successfully updated.").build();
+    }
 }

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/webapp/META-INF/permissions.xml

@@ -611,6 +611,12 @@
         <url>/policies/*</url>
         <method>Put</method>
     </Permission>
+    <Permission>
+        <name>Edit policy</name>
+        <path>/device-mgt/admin/policies/update</path>
+        <url>/policies/apply-changes</url>
+        <method>PUT</method>
+    </Permission>
     <!-- End of Policy related APIs -->
 
     <!-- Profile related APIs -->