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

   1 // Copyright 2011 Google. All Rights Reserved.
   2
   3 package com.google.apphosting.utils.config;
   4
   5 import com.google.common.base.Joiner;
   6
   7 import net.sourceforge.yamlbeans.YamlException;
   8 import net.sourceforge.yamlbeans.YamlReader;
   9
  10 import java.beans.IntrospectionException;
  11 import java.beans.PropertyDescriptor;
  12 import java.beans.SimpleBeanInfo;
  13 import java.io.File;
  14 import java.io.FileNotFoundException;
  15 import java.io.FileReader;
  16 import java.io.Reader;
  17 import java.io.StringReader;
  18 import java.util.EnumSet;
  19 import java.util.List;
  20 import java.util.Set;
  21 import java.util.ArrayList;
  22
  23 /**
  24  * JavaBean representation of the Java backends.yaml file.
  25  *
  26  */
  27 public class BackendsYamlReader {
  28
  29   public static class BackendsYaml {
  30
  31     private List<Entry> backends;
  32
  33     public List<Entry> getBackends() {
  34       return backends;
  35     }
  36
  37     public void setBackends(List<Entry> backends) {
  38       this.backends = backends;
  39     }
  40
  41     public BackendsXml toXml() {
  42       BackendsXml xml = new BackendsXml();
  43       for (Entry backend : backends) {
  44         xml.addBackend(backend.toXml());
  45       }
  46       return xml;
  47     }
  48
  49     public static class Entry {
  50       private String name;
  51       private Integer instances;
  52       private String instanceClass;
  53       private BackendsXml.State state;
  54       private Integer maxConcurrentRequests;
  55       private Set<BackendsXml.Option> options = EnumSet.noneOf(BackendsXml.Option.class);
  56
  57       public String getName() {
  58         return name;
  59       }
  60
  61       public void setName(String name) {
  62         this.name = name;
  63       }
  64
  65       public Integer getInstances() {
  66         return instances;
  67       }
  68
  69       public void setInstances(Integer instances) {
  70         this.instances = instances;
  71       }
  72
  73       public String getInstanceClass() {
  74         return instanceClass;
  75       }
  76
  77       public void setInstanceClass(String instanceClass) {
  78         this.instanceClass = instanceClass;
  79       }
  80
  81       public Integer getMax_concurrent_requests() {
  82         return maxConcurrentRequests;
  83       }
  84
  85       public void setMax_concurrent_requests(Integer maxConcurrentRequests) {
  86         this.maxConcurrentRequests = maxConcurrentRequests;
  87       }
  88
  89       public String getOptions() {
  90         List<String> optionNames = new ArrayList<String>();
  91         for (BackendsXml.Option option : options) {
  92           optionNames.add(option.getYamlValue());
  93         }
  94         return Joiner.on(", ").useForNull("null").join(optionNames);
  95       }
  96
  97       public void setOptions(String optionString) {
  98         options.clear();
  99         for (String optionName : optionString.split(" *, *")) {
 100           options.add(BackendsXml.Option.fromYamlValue(optionName));
 101         }
 102       }
 103
 104       public String getState() {
 105         return (state != null) ? state.getYamlValue() : null;
 106       }
 107
 108       public void setState(String state) {
 109         this.state = (state != null) ? BackendsXml.State.fromYamlValue(state) : null;
 110       }
 111
 112       public BackendsXml.Entry toXml() {
 113         return new BackendsXml.Entry(
 114             name,
 115             instances,
 116             instanceClass,
 117             maxConcurrentRequests,
 118             options,
 119             state);
 120       }
 121     }
 122
 123     public static class EntryBeanInfo extends SimpleBeanInfo {
 124       @Override
 125       public PropertyDescriptor[] getPropertyDescriptors() {
 126         try {
 127           return new PropertyDescriptor[] {
 128             new PropertyDescriptor("name", Entry.class),
 129             new PropertyDescriptor("instances", Entry.class),
 130             new PropertyDescriptor("class", Entry.class, "getInstanceClass", "setInstanceClass"),
 131             new PropertyDescriptor("state", Entry.class),
 132             new PropertyDescriptor("max_concurrent_requests", Entry.class),
 133             new PropertyDescriptor("options", Entry.class),
 134           };
 135         } catch (IntrospectionException ex) {
 136           throw new RuntimeException(ex);
 137         }
 138       }
 139     }
 140   }
 141
 142   private static final String FILENAME = "backends.yaml";
 143   private String appDir;
 144
 145   public BackendsYamlReader(String appDir) {
 146     if (appDir.length() > 0 && appDir.charAt(appDir.length() - 1) != File.separatorChar) {
 147       appDir += File.separatorChar;
 148     }
 149     this.appDir = appDir;
 150   }
 151
 152   public String getFilename() {
 153     return appDir + FILENAME;
 154   }
 155
 156   public BackendsXml parse() {
 157     if (new File(getFilename()).exists()) {
 158       try {
 159         return parse(new FileReader(getFilename()));
 160       } catch (FileNotFoundException ex) {
 161         throw new AppEngineConfigException("Cannot find file " + getFilename(), ex);
 162       }
 163     }
 164     return null;
 165   }
 166
 167   public static BackendsXml parse(Reader yaml) {
 168     YamlReader reader = new YamlReader(yaml);
 169     reader.getConfig().setPropertyElementType(BackendsYaml.class,
 170                                               "backends",
 171                                               BackendsYaml.Entry.class);
 172
 173     try {
 174       BackendsYaml backendsYaml = reader.read(BackendsYaml.class);
 175       if (backendsYaml == null) {
 176         throw new AppEngineConfigException("Empty backends configuration.");
 177       }
 178       return backendsYaml.toXml();
 179     } catch (YamlException ex) {
 180       throw new AppEngineConfigException(ex.getMessage(), ex);
 181     }
 182   }
 183
 184   public static BackendsXml parse(String yaml) {
 185     return parse(new StringReader(yaml));
 186   }
 187 }