import java.io.StringReader;
import java.text.SimpleDateFormat;
import java.util.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.InputSource;

public class Example2 {
    private static final String reqMsg =
        "<samlp:AttributeQuery " +
        " xmlns:samlp='urn:oasis:names:tc:SAML:2.0:protocol' " +
        " ID='%%ID%%' IssueInstant='%%ISSUEINST%%' Version='2.0'>" +
        " <saml:Issuer xmlns:saml='urn:oasis:names:tc:SAML:2.0:assertion'>"
        +
        "%%ISSUER%%" +
        " </saml:Issuer>" +
        " <saml:Subject xmlns:saml='urn:oasis:names:tc:SAML:2.0:assertion'>"
        +
        " <saml:NameID Format='urn:oasis:names:tc:SAML:2.0:nameid-format:
        unspecified'" +
        " xmlns:saml='urn:oasis:names:tc:SAML:2.0:assertion'> " +
        "%%SUBJECT%%" +
        " </saml:NameID>" +
        " </saml:Subject>" +
        "</samlp:AttributeQuery>";

    public static String getAttributeRequest(String id, String issuer, String subject) {

        Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("US/Arizona"));
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat sdfTime = new SimpleDateFormat("HH:mm:ss");
        String res = Example2.reqMsg
        res = res.replaceAll("%%ID%%", id);
        res = res.replaceAll("%%ISSUEINST%%", sdf.format(cal.getTime()) +
        "T" +
        sdfTime.format(cal.getTime()) + "Z");
        res = res.replaceAll("%%ISSUER%%", issuer);
        res = res.replaceAll("%%SUBJECT%%", subject);
        return res;
    }

    public static Element getElementFromString(String s) throws Exception {
        DocumentBuilderFactory factory = DocumentBuilderFactory.
        newInstance();
        factory.setNamespaceAware(true);
        DocumentBuilder builder = factory.newDocumentBuilder();
        InputSource is = new InputSource(new StringReader(s));
        Document d = builder.parse(is);
        return d.getDocumentElement();
    }
    public static void main(String[] args) throws Exception {
        String id = UUID.randomUUID().toString();
        String issuer = "http://www.prise.es/uoc-book/example2";
        String subject = "cr01";
        String reqMsg = getAttributeRequest(id, issuer, subject);
        System.out.println(reqMsg);
        Element req = getElementFromString(reqMsg);
    }
}