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

   1 package com.google.apphosting.utils.config;
   2
   3 import com.google.apphosting.utils.config.DispatchXml.DispatchEntry;
   4 import com.google.common.annotations.VisibleForTesting;
   5
   6 import net.sourceforge.yamlbeans.YamlException;
   7 import net.sourceforge.yamlbeans.YamlReader;
   8
   9 import java.io.File;
  10 import java.io.FileNotFoundException;
  11 import java.io.FileReader;
  12 import java.io.Reader;
  13 import java.util.List;
  14
  15 /**
  16  * Class to parse dispatch.yaml into a {@link DispatchXml}.
  17  *
  18  */
  19 public class DispatchYamlReader {
  20   private static final String DISPATCH_FILENAME = "dispatch.yaml";
  21   private final String parentDirectory;
  22
  23   /**
  24    * Constructs a {@link DispatchYamlReader}.
  25    * @param parentDirectory the directory containing the dispatch.yaml file.
  26    */
  27   public DispatchYamlReader(String parentDirectory) {
  28     if (parentDirectory.length() > 0
  29         && parentDirectory.charAt(parentDirectory.length() - 1) != File.separatorChar) {
  30       parentDirectory += File.separatorChar;
  31     }
  32     this.parentDirectory = parentDirectory;
  33   }
  34
  35   public String getFilename() {
  36     return parentDirectory + DISPATCH_FILENAME;
  37   }
  38
  39   public DispatchXml parse() {
  40     DispatchXml result = null;
  41     try {
  42       return parseImpl(new FileReader(getFilename()));
  43     } catch (FileNotFoundException ex) {
  44     }
  45     return null;
  46   }
  47
  48   @VisibleForTesting
  49   static DispatchXml parseImpl(Reader yaml) {
  50     YamlReader reader = new YamlReader(yaml);
  51     reader.getConfig().setPropertyElementType(DispatchYaml.class, "dispatch",
  52         DispatchYamlEntry.class);
  53     try {
  54       DispatchYaml dispatchYaml = reader.read(DispatchYaml.class);
  55       if (dispatchYaml == null) {
  56         throw new AppEngineConfigException("Empty dispatch.yaml configuration.");
  57       }
  58       return dispatchYaml.toXml();
  59     } catch (YamlException ex) {
  60       throw new AppEngineConfigException(ex.getMessage(), ex);
  61     }
  62   }
  63
  64   /**
  65    * Top level bean for a parsed dispatch.yaml file that meets the
  66    * requirements of {@link YamlReader}.
  67    */
  68   public static class DispatchYaml {
  69     private List<DispatchYamlEntry> dispatchEntries;
  70
  71     public List<DispatchYamlEntry> getDispatch() {
  72       return dispatchEntries;
  73     }
  74
  75     public void setDispatch(List<DispatchYamlEntry> entries) {
  76       this.dispatchEntries = entries;
  77     }
  78
  79     public DispatchXml toXml() {
  80       DispatchXml.Builder builder = DispatchXml.builder();
  81       if (dispatchEntries != null) {
  82         for (DispatchYamlEntry entry : dispatchEntries) {
  83           builder.addDispatchEntry(entry.asDispatchEntry());
  84         }
  85       }
  86       return builder.build();
  87     }
  88   }
  89
  90   /**
  91    * Bean for a parsed single uri to module mapping entry in a
  92    * dispatch.yaml file that meets the requirements of
  93    * {@link YamlReader}.
  94    */
  95   public static class DispatchYamlEntry {
  96     private String url;
  97     private String module;
  98
  99     public String getUrl() {
 100       return url;
 101     }
 102
 103     public void setUrl(String url) {
 104       this.url = url;
 105     }
 106
 107     public String getModule() {
 108       return module;
 109     }
 110
 111     public void setModule(String module) {
 112       this.module = module;
 113     }
 114
 115     DispatchEntry asDispatchEntry() {
 116       return new DispatchEntry(url, module);
 117     }
 118   }
 119 }