ph-schematron/src/main/java/com/helger/schematron/pure/exchange/PSWriter.java
@Nullable
  public String getXMLString (@Nonnull final IPSElement aPSElement)
  {
    ValueEnforcer.notNull (aPSElement, "PSElement");
    final IMicroElement eXML = aPSElement.getAsMicroElement ();
    return MicroWriter.getNodeAsString (getAsDocument (eXML), m_aWriterSettings.getXMLWriterSettings ());
  }
@Nullable
  public String getXMLString (@Nonnull final IPSElement aPSElement)
  {
    ValueEnforcer.notNull (aPSElement, "PSElement");
    final IMicroElement eXML = aPSElement.getAsMicroElement ();
    return MicroWriter.getNodeAsString (getAsDocument (eXML), m_aWriterSettings.getXMLWriterSettings ());
  }
Get the passed Schematron element as a String

@param aPSElement
The schematron element to convert to a string. May not be
<code>null</code>.
@return The passed element as a string or <code>null</code> if
serialization failed.