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

   1 /*
   2  * Sone - IdentityChangeDetector.java - Copyright © 2013 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.freenet.wot;
  19
  20 import static com.google.common.base.Optional.absent;
  21 import static com.google.common.base.Optional.fromNullable;
  22 import static com.google.common.base.Predicates.not;
  23 import static com.google.common.collect.FluentIterable.from;
  24
  25 import java.util.Collection;
  26 import java.util.Map;
  27 import java.util.Map.Entry;
  28
  29 import com.google.common.base.Optional;
  30 import com.google.common.base.Predicate;
  31 import com.google.common.collect.FluentIterable;
  32 import com.google.common.collect.ImmutableMap;
  33
  34 /**
  35  * Detects changes between two lists of {@link Identity}s. The detector can find
  36  * added and removed identities, and for identities that exist in both list
  37  * their contexts and properties are checked for added, removed, or (in case of
  38  * properties) changed values.
  39  *
  40  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  41  */
  42 public class IdentityChangeDetector {
  43
  44         private final Map<String, Identity> oldIdentities;
  45         private Optional<IdentityProcessor> onNewIdentity = absent();
  46         private Optional<IdentityProcessor> onRemovedIdentity = absent();
  47         private Optional<IdentityProcessor> onChangedIdentity = absent();
  48         private Optional<IdentityProcessor> onUnchangedIdentity = absent();
  49
  50         public IdentityChangeDetector(Collection<? extends Identity> oldIdentities) {
  51                 this.oldIdentities = convertToMap(oldIdentities);
  52         }
  53
  54         public void onNewIdentity(IdentityProcessor onNewIdentity) {
  55                 this.onNewIdentity = fromNullable(onNewIdentity);
  56         }
  57
  58         public void onRemovedIdentity(IdentityProcessor onRemovedIdentity) {
  59                 this.onRemovedIdentity = fromNullable(onRemovedIdentity);
  60         }
  61
  62         public void onChangedIdentity(IdentityProcessor onChangedIdentity) {
  63                 this.onChangedIdentity = fromNullable(onChangedIdentity);
  64         }
  65
  66         public void onUnchangedIdentity(IdentityProcessor onUnchangedIdentity) {
  67                 this.onUnchangedIdentity = fromNullable(onUnchangedIdentity);
  68         }
  69
  70         public void detectChanges(Collection<? extends Identity> newIdentities) {
  71                 notifyForRemovedIdentities(from(oldIdentities.values()).filter(notContainedIn(newIdentities)));
  72                 notifyForNewIdentities(from(newIdentities).filter(notContainedIn(oldIdentities.values())));
  73                 notifyForChangedIdentities(from(newIdentities).filter(containedIn(oldIdentities)).filter(hasChanged(oldIdentities)));
  74                 notifyForUnchangedIdentities(from(newIdentities).filter(containedIn(oldIdentities)).filter(not(hasChanged(oldIdentities))));
  75         }
  76
  77         private void notifyForRemovedIdentities(Iterable<Identity> identities) {
  78                 notify(onRemovedIdentity, identities);
  79         }
  80
  81         private void notifyForNewIdentities(FluentIterable<? extends Identity> newIdentities) {
  82                 notify(onNewIdentity, newIdentities);
  83         }
  84
  85         private void notifyForChangedIdentities(FluentIterable<? extends Identity> identities) {
  86                 notify(onChangedIdentity, identities);
  87         }
  88
  89         private void notifyForUnchangedIdentities(FluentIterable<? extends Identity> identities) {
  90                 notify(onUnchangedIdentity, identities);
  91         }
  92
  93         private void notify(Optional<IdentityProcessor> identityProcessor, Iterable<? extends Identity> identities) {
  94                 if (!identityProcessor.isPresent()) {
  95                         return;
  96                 }
  97                 for (Identity identity : identities) {
  98                         identityProcessor.get().processIdentity(identity);
  99                 }
 100         }
 101
 102         private static Predicate<Identity> hasChanged(Map<String, Identity> oldIdentities) {
 103                 return identity -> identityHasChanged(oldIdentities.get(identity.getId()), identity);
 104         }
 105
 106         private static boolean identityHasChanged(Identity oldIdentity, Identity newIdentity) {
 107                 return identityHasNewContexts(oldIdentity, newIdentity)
 108                                 || identityHasRemovedContexts(oldIdentity, newIdentity)
 109                                 || identityHasNewProperties(oldIdentity, newIdentity)
 110                                 || identityHasRemovedProperties(oldIdentity, newIdentity)
 111                                 || identityHasChangedProperties(oldIdentity, newIdentity);
 112         }
 113
 114         private static boolean identityHasNewContexts(Identity oldIdentity, Identity newIdentity) {
 115                 return from(newIdentity.getContexts()).anyMatch(notAContextOf(oldIdentity));
 116         }
 117
 118         private static boolean identityHasRemovedContexts(Identity oldIdentity, Identity newIdentity) {
 119                 return from(oldIdentity.getContexts()).anyMatch(notAContextOf(newIdentity));
 120         }
 121
 122         private static boolean identityHasNewProperties(Identity oldIdentity, Identity newIdentity) {
 123                 return from(newIdentity.getProperties().entrySet()).anyMatch(notAPropertyOf(oldIdentity));
 124         }
 125
 126         private static boolean identityHasRemovedProperties(Identity oldIdentity, Identity newIdentity) {
 127                 return from(oldIdentity.getProperties().entrySet()).anyMatch(notAPropertyOf(newIdentity));
 128         }
 129
 130         private static boolean identityHasChangedProperties(Identity oldIdentity, Identity newIdentity) {
 131                 return from(oldIdentity.getProperties().entrySet()).anyMatch(hasADifferentValueThanIn(newIdentity));
 132         }
 133
 134         private static Predicate<Identity> containedIn(Map<String, Identity> identities) {
 135                 return identity -> identities.containsKey(identity.getId());
 136         }
 137
 138         private static Predicate<String> notAContextOf(Identity identity) {
 139                 return context -> (identity != null) && !identity.getContexts().contains(context);
 140         }
 141
 142         private static Predicate<Identity> notContainedIn(Collection<? extends Identity> newIdentities) {
 143                 return identity -> (identity != null) && !newIdentities.contains(identity);
 144         }
 145
 146         private static Predicate<Entry<String, String>> notAPropertyOf(Identity identity) {
 147                 return property -> (property != null) && !identity.getProperties().containsKey(property.getKey());
 148         }
 149
 150         private static Predicate<Entry<String, String>> hasADifferentValueThanIn(Identity newIdentity) {
 151                 return property ->
 152                                 (property != null) && !newIdentity.getProperty(property.getKey()).equals(property.getValue());
 153         }
 154
 155         private static Map<String, Identity> convertToMap(Collection<? extends Identity> identities) {
 156                 ImmutableMap.Builder<String, Identity> mapBuilder = ImmutableMap.builder();
 157                 for (Identity identity : identities) {
 158                         mapBuilder.put(identity.getId(), identity);
 159                 }
 160                 return mapBuilder.build();
 161         }
 162
 163         public interface IdentityProcessor {
 164
 165                 void processIdentity(Identity identity);
 166
 167         }
 168
 169 }