java/src/main/com/google/appengine/tools/admin/CronEntryImpl.java

   1 // Copyright 2009 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.tools.admin;
   4
   5 import com.google.cron.GrocTimeSpecification;
   6
   7 import java.text.DateFormat;
   8 import java.text.SimpleDateFormat;
   9 import java.util.Date;
  10 import java.util.Iterator;
  11 import java.util.TimeZone;
  12
  13 /**
  14  * Implementation of the CronEntry interface used to describe a single cron
  15  * task.
  16  *
  17  */
  18 public class CronEntryImpl implements CronEntry {
  19
  20   private final DateFormat formatter;
  21
  22   private final String url;
  23   private final String description;
  24   private final String schedule;
  25   private final String tz;
  26
  27   public CronEntryImpl(String url, String description, String schedule, String tz) {
  28     this.url = url;
  29     this.description = description;
  30     this.schedule = schedule;
  31     this.tz = (tz == null) ? "UTC" : tz;
  32     formatter = new SimpleDateFormat("EEE MMM dd, yyyy HH:mm z (Z)");
  33     formatter.setTimeZone(TimeZone.getTimeZone(this.tz));
  34   }
  35
  36   @Override
  37   public String getDescription() {
  38     return description;
  39   }
  40
  41   @Override
  42   public Iterator<String> getNextTimesIterator() {
  43     return new TimeIterator(new Date(),
  44         GrocTimeSpecification.create(schedule, TimeZone.getTimeZone(tz)));
  45   }
  46
  47   /**
  48    * Test variant of {@link #getNextTimesIterator()}, with a specified start.
  49    */
  50   Iterator<String> getNextTimesIterator(Date start) {
  51     return new TimeIterator(start,
  52         GrocTimeSpecification.create(schedule, TimeZone.getTimeZone(tz)));
  53   }
  54
  55   @Override
  56   public String getSchedule() {
  57     return schedule;
  58   }
  59
  60   public String getTimezone() {
  61     return tz;
  62   }
  63
  64   @Override
  65   public String getUrl() {
  66     return url;
  67   }
  68
  69   @Override
  70   public String toXml() {
  71       String result =
  72         "<cron>\n" +
  73           "  <url>" + url + "</url>\n" +
  74           "  <schedule>" + schedule + "</schedule>\n" +
  75           "  <timezone>" + tz + "</timezone>\n";
  76       if (description != null) {
  77         result = result + "  <description>" + description + "</description>\n";
  78       }
  79       return result + "</cron>";
  80   }
  81
  82   /**
  83    * An iterator tracking the last execution time, and the groc time
  84    * specification object to compute future execution times.
  85    */
  86   public class TimeIterator implements Iterator<String> {
  87
  88     private Date lastRun;
  89     private GrocTimeSpecification groc;
  90
  91     public TimeIterator(Date seedTime, GrocTimeSpecification groc) {
  92       lastRun = seedTime;
  93       this.groc = groc;
  94     }
  95
  96     @Override
  97     public boolean hasNext() {
  98       return true;
  99     }
 100
 101     @Override
 102     public String next() {
 103       lastRun = groc.getMatch(lastRun);
 104       String result = formatter.format(lastRun);
 105       return result;
 106     }
 107
 108     @Override
 109     public void remove() {
 110       throw new UnsupportedOperationException("cron execution times cannot be removed");
 111     }
 112   }
 113 }