@Override
 protected ValidationResult compute() {
   String projectName = projectNameField.getValue();
   if (projectName == null) {
     return error("Project name is undefined");
   } else if ("".equals(projectName)) {
     return error("Project name is empty");
   } else if (projectName.indexOf(' ') >= 0) {
     return error("Project name contains spaces");
   } else if (existsInWorkspace(projectName)) {
     return error("A project with name '" + projectName + "' already exists in the workspace.");
   } else {
     for (int i = 0; i < projectName.length(); i++) {
       char c = projectName.charAt(i);
       if (!isAllowedChar(c)) {
         return error("Project name contains forbidden character '" + c + "'");
       }
     }
   }
   return ValidationResult.OK;
 }