org.argeo.init/src/org/argeo/init/prefs/SystemRootPreferences.java

   1 package org.argeo.init.prefs;
   2
   3 import java.util.concurrent.CompletableFuture;
   4 import java.util.concurrent.ExecutionException;
   5 import java.util.function.Consumer;
   6 import java.util.prefs.AbstractPreferences;
   7 import java.util.prefs.BackingStoreException;
   8
   9 public class SystemRootPreferences extends AbstractPreferences implements Consumer<AbstractPreferences> {
  10         private CompletableFuture<AbstractPreferences> singleChild;
  11
  12         protected SystemRootPreferences() {
  13                 super(null, "");
  14         }
  15
  16         @Override
  17         public void accept(AbstractPreferences t) {
  18                 this.singleChild.complete(t);
  19         }
  20
  21         /*
  22          * ABSTRACT PREFERENCES
  23          */
  24
  25         @Override
  26         protected void putSpi(String key, String value) {
  27                 throw new UnsupportedOperationException();
  28         }
  29
  30         @Override
  31         protected String getSpi(String key) {
  32                 throw new UnsupportedOperationException();
  33         }
  34
  35         @Override
  36         protected void removeSpi(String key) {
  37                 throw new UnsupportedOperationException();
  38         }
  39
  40         @Override
  41         protected void removeNodeSpi() throws BackingStoreException {
  42                 throw new UnsupportedOperationException();
  43         }
  44
  45         @Override
  46         protected String[] keysSpi() throws BackingStoreException {
  47                 return new String[0];
  48         }
  49
  50         /** Will block. */
  51         @Override
  52         protected String[] childrenNamesSpi() throws BackingStoreException {
  53                 String childName;
  54                 try {
  55                         childName = singleChild.get().name();
  56                 } catch (InterruptedException | ExecutionException e) {
  57                         throw new IllegalStateException("Cannot get child preferences name", e);
  58                 }
  59                 return new String[] { childName };
  60         }
  61
  62         @Override
  63         protected AbstractPreferences childSpi(String name) {
  64                 String childName;
  65                 try {
  66                         childName = singleChild.get().name();
  67                 } catch (InterruptedException | ExecutionException e) {
  68                         throw new IllegalStateException("Cannot get child preferences name", e);
  69                 }
  70                 if (!childName.equals(name))
  71                         throw new IllegalArgumentException("Child name is " + childName + ", not " + name);
  72                 return null;
  73         }
  74
  75         @Override
  76         protected void syncSpi() throws BackingStoreException {
  77         }
  78
  79         @Override
  80         protected void flushSpi() throws BackingStoreException {
  81         }
  82
  83 }