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

   1 // Copyright 2008 Google Inc. All Rights Reserved.
   2 package com.google.apphosting.utils.config;
   3
   4 import org.mortbay.xml.XmlParser.Node;
   5
   6 import java.io.InputStream;
   7 import java.util.Stack;
   8
   9 /**
  10  * Creates an {@link CronXml} instance from
  11  * <appdir>WEB-INF/cron.xml.  If you want to read the configuration
  12  * from a different file, subclass and override {@link #getFilename()}.  If you
  13  * want to read the configuration from something that isn't a file, subclass
  14  * and override {@link #getInputStream()}.
  15  *
  16  */
  17 public class CronXmlReader extends AbstractConfigXmlReader<CronXml> {
  18
  19   private static final String FILENAME = "WEB-INF/cron.xml";
  20
  21   private static final String CRONENTRIES_TAG = "cronentries";
  22   private static final String CRON_TAG = "cron";
  23   private static final String DESCRIPTION_TAG = "description";
  24   private static final String SCHEDULE_TAG = "schedule";
  25   private static final String TARGET_TAG = "target";
  26   private static final String TIMEZONE_TAG = "timezone";
  27   private static final String URL_TAG = "url";
  28
  29   /**
  30    * Constructs the reader for {@code cron.xml} in a given application directory.
  31    * @param appDir the application directory
  32    */
  33   public CronXmlReader(String appDir) {
  34     super(appDir, false);
  35   }
  36
  37   /**
  38    * Parses the config file.
  39    * @return A {@link CronXml} object representing the parsed configuration.
  40    */
  41   public CronXml readCronXml() {
  42     return readConfigXml();
  43   }
  44
  45   @Override
  46   protected CronXml processXml(InputStream is) {
  47     final CronXml cronXml = new CronXml();
  48     parse(new ParserCallback() {
  49       boolean first = true;
  50       CronXml.Entry entry;
  51
  52       @Override
  53       public void newNode(Node node, Stack<Node> ancestors) {
  54         switch (ancestors.size()) {
  55           case 0:
  56             if (!CRONENTRIES_TAG.equalsIgnoreCase(node.getTag())) {
  57               throw new AppEngineConfigException(getFilename() + " does not contain <"
  58                   + CRONENTRIES_TAG + ">");
  59             }
  60             if (!first) {
  61               throw new AppEngineConfigException(getFilename() + " contains multiple <"
  62                   + CRONENTRIES_TAG + ">");
  63             }
  64             first = false;
  65             break;
  66
  67           case 1:
  68             if (CRON_TAG.equalsIgnoreCase(node.getTag())) {
  69               entry = cronXml.addNewEntry();
  70             } else {
  71               throw new AppEngineConfigException(getFilename() + " contains <"
  72                   + node.getTag() + "> instead of <" + CRON_TAG + "/>");
  73             }
  74             break;
  75
  76           case 2:
  77             assert(entry != null);
  78             if (DESCRIPTION_TAG.equalsIgnoreCase(node.getTag())) {
  79               if (node.size() == 1 && node.get(0) instanceof String) {
  80                 entry.setDescription((String) node.get(0));
  81               } else {
  82                 throw new AppEngineConfigException(getFilename() + " has bad contents in <"
  83                     + DESCRIPTION_TAG + ">");
  84               }
  85             } else if (URL_TAG.equalsIgnoreCase(node.getTag())) {
  86                 if (node.size() == 1 && node.get(0) instanceof String) {
  87                   entry.setUrl((String) node.get(0));
  88                 } else {
  89                   throw new AppEngineConfigException(getFilename() + " has bad contents in <"
  90                       + URL_TAG + ">");
  91                 }
  92             } else if (SCHEDULE_TAG.equalsIgnoreCase(node.getTag())) {
  93               if (node.size() == 1 && node.get(0) instanceof String) {
  94                 entry.setSchedule((String) node.get(0));
  95               } else {
  96                 throw new AppEngineConfigException(getFilename() + " has bad contents in <"
  97                     + SCHEDULE_TAG + ">");
  98               }
  99             } else if (TIMEZONE_TAG.equalsIgnoreCase(node.getTag())) {
 100               if (node.size() == 1 && node.get(0) instanceof String) {
 101                 entry.setTimezone((String) node.get(0));
 102               } else {
 103                 throw new AppEngineConfigException(getFilename() + " has bad contents in <"
 104                     + TIMEZONE_TAG + ">");
 105               }
 106             } else if (TARGET_TAG.equalsIgnoreCase(node.getTag())) {
 107               if (node.size() == 1 && node.get(0) instanceof String) {
 108                 entry.setTarget((String) node.get(0));
 109               } else {
 110                 throw new AppEngineConfigException(getFilename() + " has bad contents in <"
 111                     + TARGET_TAG + ">");
 112               }
 113             } else {
 114               throw new AppEngineConfigException(getFilename() + " contains unknown <"
 115                   + node.getTag() + "> inside <" + CRON_TAG + "/>");
 116             }
 117             break;
 118
 119           default:
 120             throw new AppEngineConfigException(getFilename()
 121                 + " has a syntax error; node <"
 122                 + node.getTag() + "> is too deeply nested to be valid.");
 123         }
 124       }
 125     }, is);
 126     cronXml.validateLastEntry();
 127     return cronXml;
 128   }
 129
 130   @Override
 131   protected String getRelativeFilename() {
 132     return FILENAME;
 133   }
 134
 135 }