java/src/main/com/google/apphosting/utils/config/AppEngineApplicationXmlReader.java

   1 package com.google.apphosting.utils.config;
   2
   3 import org.mortbay.xml.XmlParser;
   4
   5 import java.io.InputStream;
   6
   7 /**
   8  * Constructs an {@link AppEngineApplicationXml} from an xml document
   9  * corresponding to appengine-application.xsd.
  10  *
  11  * <p>We use Jetty's {@link XmlParser} utility to match other Appengine XML
  12  * parsing code.
  13  *
  14  */
  15 public class AppEngineApplicationXmlReader {
  16   private static final String EMPTY_STRING = "";
  17
  18   /**
  19    * Construct an {@link AppEngineApplicationXml} from the xml document
  20    * within the provided {@link InputStream}.
  21    *
  22    * @param is The InputStream containing the xml we want to parse and process
  23    *
  24    * @return Object representation of the xml document
  25    * @throws AppEngineConfigException If the input stream cannot be parsed
  26    */
  27   public AppEngineApplicationXml processXml(InputStream is) throws AppEngineConfigException {
  28     AppEngineApplicationXml.Builder builder = new AppEngineApplicationXml.Builder();
  29     String applicationId = EMPTY_STRING;
  30     for (Object o : XmlUtils.parse(is)) {
  31       if (!(o instanceof XmlParser.Node)) {
  32         continue;
  33       }
  34       XmlParser.Node node = (XmlParser.Node) o;
  35       if (node.getTag().equals("application")) {
  36         applicationId = XmlUtils.getText(node);
  37       } else {
  38         throw new AppEngineConfigException("Unrecognized element <" + node.getTag()
  39             + "> in appengine-application.xml.");
  40       }
  41     }
  42     if (applicationId.equals(EMPTY_STRING)) {
  43       throw new AppEngineConfigException(
  44           "Missing or empty <application> element in appengine-application.xml.");
  45     }
  46     return builder.setApplicationId(applicationId).build();
  47   }
  48 }