src/main/java/net/pterodactylus/sone/data/IdBuilder.java

   1 package net.pterodactylus.sone.data;
   2
   3 import javax.annotation.Nonnull;
   4 import javax.annotation.concurrent.ThreadSafe;
   5
   6 import com.google.common.base.Charsets;
   7 import com.google.common.hash.HashFunction;
   8 import com.google.common.hash.Hashing;
   9
  10 /**
  11  * Builds (practically) unique IDs by combining Sone and element IDs.
  12  *
  13  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  14  */
  15 @ThreadSafe
  16 public class IdBuilder {
  17
  18         private static final HashFunction HASH_FUNCTION = Hashing.sha256();
  19         public static final int ID_STRING_LENGTH = HASH_FUNCTION.bits() / 4;
  20
  21         private final HashFunction sha256 = HASH_FUNCTION;
  22
  23         @Nonnull
  24         public String buildId(@Nonnull String soneId, @Nonnull String id) {
  25                 return sha256.newHasher()
  26                                 .putBytes(soneId.getBytes(Charsets.UTF_8))
  27                                 .putBytes(id.getBytes(Charsets.UTF_8))
  28                                 .hash().toString();
  29         }
  30
  31 }