rspec/rules/S6399/java/how-to-fix-it/java-se.adoc

== How to fix it in Java SE

=== Code examples

include::../../common/fix/code-rationale.adoc[]

==== Noncompliant code example

[source,java,diff-id=1,diff-type=noncompliant]
----
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    String xml = "<node id=\""+req.getParameter("id")+"\"></node>";
    
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    try {
        DocumentBuilder builder = factory.newDocumentBuilder();
        builder.parse(new InputSource(new StringReader(xml)); // Noncompliant
    } catch (ParserConfigurationException | SAXException e) {
        resp.sendError(400);
    }
}
----

==== Compliant solution

[source,java,diff-id=1,diff-type=compliant]
----
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    String xml = "<node></node>";
    
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    try {
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document doc = builder.parse(new InputSource(new StringReader(xml));
        Element element = (Element) doc.getElementsByTagName("node").item(0);
        element.setAttribute("id", req.getParameter("id"));
    } catch (ParserConfigurationException | SAXException e) {
        resp.sendError(400);
    }
}
----

=== How does this work?

include::../../common/fix/introduction.adoc[]

include::../../common/fix/object.adoc[]

The example compliant code takes advantage of the `javax.xml` and `org.w3c.dom`
libraries capabilities to programmatically build XML documents.

include::../../common/fix/casting.adoc[]