package org.tinyjee.maven.dim.utils;
   
   import org.xml.sax.EntityResolver;
   import org.xml.sax.InputSource;
   import org.xml.sax.SAXException;
   
   import javax.xml.transform.Source;
   import javax.xml.transform.TransformerException;
   import javax.xml.transform.URIResolver;
  import java.io.IOException;
  import java.net.URL;
  
  /**
   * This is a simple DTD resolver that attempts to load DTDs from the classpath first
   * before delegating to a web query.
   * <p/>
   * It is doing so by translating any HTTP systemIds to local classpath URLs using the
   * common translation rule between HTTP-url and CP url.
   *
   * @author Juergen_Kellerer, 2011-09-28
   */
  public class XhtmlEntityResolver implements EntityResolver {
  	public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException {
  		if (systemId.startsWith("http")) {
  			URL systemIdUrl = new URL(systemId);
  
  			StringBuilder newPath = new StringBuilder(systemId.length());
  			String[] domainParts = systemIdUrl.getHost().split("\\.");
  			for (int i = domainParts.length - 1; i > 0; i--) newPath.append('/').append(domainParts[i]);
  			newPath.append(systemIdUrl.getPath());
  
  			URL resource = getClass().getResource(newPath.toString());
  			if (resource != null) {
  				InputSource inputSource = new InputSource(resource.toExternalForm());
  				inputSource.setPublicId(publicId);
  				return inputSource;
  			}
  		}
  
  		return null;
  	}
  }