public Signer(Request request,String contentSha256,DateTime date,String region,String accessKey,String secretKey){
  this.request=request;
  this.contentSha256=contentSha256;
  this.date=date;
  this.region=region;
  this.accessKey=accessKey;
  this.secretKey=secretKey;
}

public Signer ( Request request , String contentSha256 , DateTime date , String region , String accessKey , String secretKey ) { this . request = request ; this . contentSha256 = contentSha256 ; this . date = date ; this . region = region ; this . accessKey = accessKey ; this . secretKey = secretKey ; }
create new signer object for v4 .
