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

   1 // Copyright 2010 Google Inc. All Rights Reserved.
   2
   3 package com.google.apphosting.utils.config;
   4
   5 import java.io.File;
   6 import java.io.FileReader;
   7 import java.io.FileNotFoundException;
   8 import java.io.Reader;
   9 import java.io.StringReader;
  10 import java.util.List;
  11 import net.sourceforge.yamlbeans.YamlException;
  12 import net.sourceforge.yamlbeans.YamlReader;
  13
  14 /**
  15  * Class to parse queue.yaml into a QueueXml object.
  16  *
  17  */
  18 public class CronYamlReader {
  19
  20   /**
  21    * Wrapper around CronXml to make the JavaBeans properties match the YAML file syntax.
  22    */
  23   public static class CronYaml {
  24     private List<CronXml.Entry> entries;
  25
  26     public List<CronXml.Entry> getCron() {
  27       return entries;
  28     }
  29
  30     public void setCron(List<CronXml.Entry> entries) {
  31       this.entries = entries;
  32     }
  33
  34     public CronXml toXml() {
  35       CronXml xml = new CronXml();
  36       if (entries != null) {
  37         for (CronXml.Entry entry : entries) {
  38           xml.addEntry(entry);
  39         }
  40       }
  41       return xml;
  42     }
  43   }
  44
  45   private static final String FILENAME = "cron.yaml";
  46   private String appDir;
  47
  48   public CronYamlReader(String appDir) {
  49     if (appDir.length() > 0 && appDir.charAt(appDir.length() - 1) != File.separatorChar) {
  50       appDir += File.separatorChar;
  51     }
  52     this.appDir = appDir;
  53   }
  54
  55   public String getFilename() {
  56     return appDir + CronYamlReader.FILENAME;
  57   }
  58
  59   public CronXml parse() {
  60     if (new File(getFilename()).exists()) {
  61       try {
  62         return parse(new FileReader(getFilename()));
  63       } catch (FileNotFoundException ex) {
  64         throw new AppEngineConfigException("Cannot find file " + getFilename(), ex);
  65       }
  66     }
  67     return null;
  68   }
  69
  70   public static CronXml parse(Reader yaml) {
  71     YamlReader reader = new YamlReader(yaml);
  72     reader.getConfig().setPropertyElementType(CronYaml.class,
  73                                               "cron",
  74                                               CronXml.Entry.class);
  75     try {
  76       CronYaml cronYaml = reader.read(CronYaml.class);
  77       if (cronYaml == null) {
  78         throw new AppEngineConfigException("Empty cron configuration.");
  79       }
  80       return cronYaml.toXml();
  81     } catch (YamlException ex) {
  82       throw new AppEngineConfigException(ex.getMessage(), ex);
  83     }
  84   }
  85
  86   public static CronXml parse(String yaml) {
  87     return parse(new StringReader(yaml));
  88   }
  89 }