src/main/java/net/pterodactylus/sone/freenet/wot/IdentityChangeDetector.kt

   1 /*
   2  * Sone - IdentityChangeDetector.kt - Copyright © 2013–2019 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sone.freenet.wot
  19
  20 /**
  21  * Detects changes between two lists of [Identity]s. The detector can find
  22  * added and removed identities, and for identities that exist in both list
  23  * their contexts and properties are checked for added, removed, or (in case of
  24  * properties) changed values.
  25  */
  26 class IdentityChangeDetector(oldIdentities: Collection<Identity>) {
  27
  28         private val oldIdentities: Map<String, Identity> = oldIdentities.associateBy { it.id }
  29         var onNewIdentity: IdentityProcessor? = null
  30         var onRemovedIdentity: IdentityProcessor? = null
  31         var onChangedIdentity: IdentityProcessor? = null
  32         var onUnchangedIdentity: IdentityProcessor? = null
  33
  34         fun detectChanges(newIdentities: Collection<Identity>) {
  35                 onRemovedIdentity.notify(oldIdentities.values.filter { it !in newIdentities })
  36                 onNewIdentity.notify(newIdentities.filter { it !in oldIdentities.values })
  37                 onChangedIdentity.notify(newIdentities.filter { it.id in oldIdentities }.filter { identityHasChanged(oldIdentities[it.id]!!, it) })
  38                 onUnchangedIdentity.notify(newIdentities.filter { it.id in oldIdentities }.filterNot { identityHasChanged(oldIdentities[it.id]!!, it) })
  39         }
  40
  41         private fun identityHasChanged(oldIdentity: Identity, newIdentity: Identity?) =
  42                         identityHasNewContexts(oldIdentity, newIdentity!!)
  43                                         || identityHasRemovedContexts(oldIdentity, newIdentity)
  44                                         || identityHasNewProperties(oldIdentity, newIdentity)
  45                                         || identityHasRemovedProperties(oldIdentity, newIdentity)
  46                                         || identityHasChangedProperties(oldIdentity, newIdentity)
  47
  48         private fun identityHasNewContexts(oldIdentity: Identity, newIdentity: Identity) =
  49                         newIdentity.contexts.any { it !in oldIdentity.contexts }
  50
  51         private fun identityHasRemovedContexts(oldIdentity: Identity, newIdentity: Identity) =
  52                         oldIdentity.contexts.any { it !in newIdentity.contexts }
  53
  54         private fun identityHasNewProperties(oldIdentity: Identity, newIdentity: Identity) =
  55                         newIdentity.properties.keys.any { it !in oldIdentity.properties }
  56
  57         private fun identityHasRemovedProperties(oldIdentity: Identity, newIdentity: Identity) =
  58                         oldIdentity.properties.keys.any { it !in newIdentity.properties }
  59
  60         private fun identityHasChangedProperties(oldIdentity: Identity, newIdentity: Identity) =
  61                         oldIdentity.properties.entries.any { newIdentity.properties[it.key] != it.value }
  62
  63 }
  64
  65 typealias IdentityProcessor = (Identity) -> Unit
  66
  67 private fun IdentityProcessor?.notify(identities: Iterable<Identity>) =
  68                 this?.let { identities.forEach(this::invoke) }