add api for get visible roles

components/device-mgt/io.entgra.device.mgt.core.device.mgt.api/src/main/java/io/entgra/device/mgt/core/device/mgt/api/jaxrs/service/api/RoleManagementService.java

@@ -187,6 +187,104 @@ public interface RoleManagementService {
                     defaultValue = "5")
             @QueryParam("limit") int limit);
 
+    @GET
+    @Path("/visible/{metaKey}")
+    @ApiOperation(
+            produces = MediaType.APPLICATION_JSON,
+            httpMethod = "GET",
+            value = "Getting the List of Visible Roles",
+            notes = "WSO2 IoTS supports role-based access control (RBAC) and role management. Using this API you can the list of roles that are in WSO2 IoTS.\n" +
+                    "Note: Internal roles, roles created for service-providers, and application related roles will not be given in the output.",
+            tags = "Role Management",
+            extensions = {
+                    @Extension(properties = {
+                            @ExtensionProperty(name = Constants.SCOPE, value = "perm:roles:view")
+                    })
+            }
+    )
+    @ApiResponses(value = {
+            @ApiResponse(
+                    code = 200,
+                    message = "OK. \n Successfully fetched the list of roles in WSO2 IoTS.",
+                    response = RoleList.class,
+                    responseHeaders = {
+                            @ResponseHeader(
+                                    name = "Content-Type",
+                                    description = "The content type of the body"),
+                            @ResponseHeader(
+                                    name = "ETag",
+                                    description = "Entity Tag of the response resource.\n" +
+                                            "Used by caches, or in conditional requests."),
+                            @ResponseHeader(
+                                    name = "Last-Modified",
+                                    description = "Date and time the resource has been modified the last time.\n" +
+                                            "Used by caches, or in conditional requests."),
+                    }),
+            @ApiResponse(
+                    code = 304,
+                    message = "Not Modified. \n Empty body because the client already has the latest version of the " +
+                            "requested resource."),
+            @ApiResponse(
+                    code = 404,
+                    message = "Not Found. \n The specified resource does not exist.\n",
+                    response = ErrorResponse.class),
+            @ApiResponse(
+                    code = 406,
+                    message = "Not Acceptable.\n The requested media type is not supported",
+                    response = ErrorResponse.class),
+            @ApiResponse(
+                    code = 500,
+                    message = "Internal Server Error. \n Server error occurred while fetching the list of roles" +
+                            " assigned to the specified user.",
+                    response = ErrorResponse.class)
+    })
+    Response getVisibleRole(
+            @ApiParam(
+                    name = "filter",
+                    value = "Provide a character or a few characters in the role name.",
+                    required = false)
+            @QueryParam("filter") String filter,
+            @ApiParam(
+                    name = "user-store",
+                    value = "The name of the UserStore you wish to get the list of roles.",
+                    required = false)
+            @QueryParam("user-store") String userStoreName,
+            @ApiParam(
+                    name = "If-Modified-Since",
+                    value = "Checks if the requested variant was modified, since the specified date-time." +
+                            "Provide the value in the following format: EEE, d MMM yyyy HH:mm:ss Z.\n" +
+                            "Example: Mon, 05 Jan 2014 15:10:00 +0200",
+                    required = false)
+            @HeaderParam("If-Modified-Since") String ifModifiedSince,
+            @ApiParam(
+                    name = "offset",
+                    value = "The starting pagination index for the complete list of qualified items.",
+                    required = false,
+                    defaultValue = "0")
+            @QueryParam("offset") int offset,
+            @ApiParam(
+                    name = "limit",
+                    value = "Provide how many role details you require from the starting pagination index/offset.",
+                    required = false,
+                    defaultValue = "5")
+            @QueryParam("limit") int limit,
+            @ApiParam(
+                    name = "username",
+                    value = "The username of the user.",
+                    required = true,
+                    defaultValue = "admin")
+            @QueryParam("username") String username,
+            @ApiParam(
+                    name = "domain",
+                    value = "The domain name of the user store.",
+                    required = false)
+            @QueryParam("domain") String domain,
+            @ApiParam(
+                    name = "metaKey",
+                    value = "Key of the metadata",
+                    required = true)
+            @PathParam("metaKey") String metaKey);
+
         @GET
         @Path("/filter/{prefix}")
         @ApiOperation(

components/device-mgt/io.entgra.device.mgt.core.device.mgt.api/src/main/java/io/entgra/device/mgt/core/device/mgt/api/jaxrs/service/impl/RoleManagementServiceImpl.java

@@ -17,6 +17,12 @@
  */
 package io.entgra.device.mgt.core.device.mgt.api.jaxrs.service.impl;
 
+import io.entgra.device.mgt.core.device.mgt.common.exceptions.MetadataManagementException;
+import io.entgra.device.mgt.core.device.mgt.common.metadata.mgt.Metadata;
+import org.apache.axis2.databinding.types.xsd._boolean;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
 import io.entgra.device.mgt.core.device.mgt.api.jaxrs.beans.ErrorResponse;
 import io.entgra.device.mgt.core.device.mgt.api.jaxrs.beans.RoleInfo;
 import io.entgra.device.mgt.core.device.mgt.api.jaxrs.beans.RoleList;
@@ -97,6 +103,91 @@ public class RoleManagementServiceImpl implements RoleManagementService {
         }
     }
 
+    @GET
+    @Path("/visible/{metaKey}")
+    @Override
+    public Response getVisibleRole(
+            @QueryParam("filter") String filter,
+            @QueryParam("user-store") String userStore,
+            @HeaderParam("If-Modified-Since") String ifModifiedSince,
+            @QueryParam("offset") int offset, @QueryParam("limit") int limit,
+            @QueryParam("username") String username, @QueryParam("domain") String domain,
+            @PathParam("metaKey") String metaKey) {
+        RequestValidationUtil.validatePaginationParameters(offset, limit);
+        if (limit == 0){
+            limit = Constants.DEFAULT_PAGE_LIMIT;
+        }
+        if (domain != null && !domain.isEmpty()) {
+            username = domain + '/' + username;
+        }
+        Metadata metadata;
+        List<String> visibleRoles;
+        RoleList visibleRoleList = new RoleList();
+        try {
+            metadata = DeviceMgtAPIUtils.getMetadataManagementService().retrieveMetadata(metaKey);
+            String metaValue = metadata.getMetaValue();
+            JSONParser parser = new JSONParser();
+            JSONObject jsonObject = (JSONObject) parser.parse(metaValue);
+            boolean decision = (boolean) jsonObject.get("isUserAbleToViewAllRoles");
+            if (decision) {
+                if(userStore == null || "".equals(userStore)){
+                    userStore = PRIMARY_USER_STORE;
+                }
+                try{
+                    visibleRoles =getRolesFromUserStore(filter, userStore);
+                    visibleRoleList.setList(visibleRoles);
+
+                    visibleRoles = FilteringUtil.getFilteredList(getRolesFromUserStore(filter, userStore), offset, limit);
+                    visibleRoleList.setList(visibleRoles);
+
+                    return Response.status(Response.Status.OK).entity(visibleRoleList).build();
+                } catch (UserStoreException e) {
+                    String msg = "Error occurred while retrieving roles from the underlying user stores";
+                    log.error(msg, e);
+                    return Response.serverError().entity(
+                            new ErrorResponse.ErrorResponseBuilder().setMessage(msg).build()).build();
+                }
+            } else {
+                try{UserStoreManager userStoreManager = DeviceMgtAPIUtils.getUserStoreManager();
+                    if (!userStoreManager.isExistingUser(username)) {
+                        if (log.isDebugEnabled()) {
+                            log.debug("User by username: " + username + " does not exist for role retrieval.");
+                        }
+                        String msg = "User by username: " + username + " does not exist for role retrieval.";
+                        return Response.status(Response.Status.NOT_FOUND).entity(msg).build();
+                    }
+                    visibleRoleList.setList(getFilteredVisibleRoles(userStoreManager, username));
+
+                    return Response.status(Response.Status.OK).entity(visibleRoleList).build();
+                }catch (UserStoreException e) {
+                    String msg = "Error occurred while trying to retrieve roles of the user '" + username + "'";
+                    log.error(msg, e);
+                    return Response.serverError().entity(
+                            new ErrorResponse.ErrorResponseBuilder().setMessage(msg).build()).build();
+                }
+            }
+        } catch (MetadataManagementException e) {
+            String msg = "Error occurred while getting the metadata entry for metaKey:" + metaKey;
+            log.error(msg, e);
+            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
+        } catch (ParseException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private List<String> getFilteredVisibleRoles(UserStoreManager userStoreManager, String username)
+            throws UserStoreException {
+        String[] roleListOfUser;
+        roleListOfUser = userStoreManager.getRoleListOfUser(username);
+        List<String> filteredRoles = new ArrayList<>();
+        for (String role : roleListOfUser) {
+            if (!(role.startsWith("Internal/") || role.startsWith("Authentication/"))) {
+                filteredRoles.add(role);
+            }
+        }
+        return filteredRoles;
+    }
+
     @GET
     @Path("/filter/{prefix}")
     @Override