2 * Sone - IdentityChangeDetector.java - Copyright © 2013–2016 David Roden
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.
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.
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/>.
18 package net.pterodactylus.sone.freenet.wot;
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 import static net.pterodactylus.sone.freenet.wot.Identity.TO_CONTEXTS;
25 import static net.pterodactylus.sone.freenet.wot.Identity.TO_PROPERTIES;
27 import java.util.Collection;
29 import java.util.Map.Entry;
31 import com.google.common.base.Optional;
32 import com.google.common.base.Predicate;
33 import com.google.common.collect.FluentIterable;
34 import com.google.common.collect.ImmutableMap;
37 * Detects changes between two lists of {@link Identity}s. The detector can find
38 * added and removed identities, and for identities that exist in both list
39 * their contexts and properties are checked for added, removed, or (in case of
40 * properties) changed values.
42 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
44 public class IdentityChangeDetector {
46 private final Map<String, Identity> oldIdentities;
47 private Optional<IdentityProcessor> onNewIdentity = absent();
48 private Optional<IdentityProcessor> onRemovedIdentity = absent();
49 private Optional<IdentityProcessor> onChangedIdentity = absent();
50 private Optional<IdentityProcessor> onUnchangedIdentity = absent();
52 public IdentityChangeDetector(Collection<? extends Identity> oldIdentities) {
53 this.oldIdentities = convertToMap(oldIdentities);
56 public void onNewIdentity(IdentityProcessor onNewIdentity) {
57 this.onNewIdentity = fromNullable(onNewIdentity);
60 public void onRemovedIdentity(IdentityProcessor onRemovedIdentity) {
61 this.onRemovedIdentity = fromNullable(onRemovedIdentity);
64 public void onChangedIdentity(IdentityProcessor onChangedIdentity) {
65 this.onChangedIdentity = fromNullable(onChangedIdentity);
68 public void onUnchangedIdentity(IdentityProcessor onUnchangedIdentity) {
69 this.onUnchangedIdentity = fromNullable(onUnchangedIdentity);
72 public void detectChanges(final Collection<? extends Identity> newIdentities) {
73 notifyForRemovedIdentities(from(oldIdentities.values()).filter(notContainedIn(newIdentities)));
74 notifyForNewIdentities(from(newIdentities).filter(notContainedIn(oldIdentities.values())));
75 notifyForChangedIdentities(from(newIdentities).filter(containedIn(oldIdentities)).filter(hasChanged(oldIdentities)));
76 notifyForUnchangedIdentities(from(newIdentities).filter(containedIn(oldIdentities)).filter(not(hasChanged(oldIdentities))));
79 private void notifyForRemovedIdentities(Iterable<Identity> identities) {
80 notify(onRemovedIdentity, identities);
83 private void notifyForNewIdentities(FluentIterable<? extends Identity> newIdentities) {
84 notify(onNewIdentity, newIdentities);
87 private void notifyForChangedIdentities(FluentIterable<? extends Identity> identities) {
88 notify(onChangedIdentity, identities);
91 private void notifyForUnchangedIdentities(FluentIterable<? extends Identity> identities) {
92 notify(onUnchangedIdentity, identities);
95 private void notify(Optional<IdentityProcessor> identityProcessor, Iterable<? extends Identity> identities) {
96 if (!identityProcessor.isPresent()) {
99 for (Identity identity : identities) {
100 identityProcessor.get().processIdentity(identity);
104 private static Predicate<Identity> hasChanged(final Map<String, Identity> oldIdentities) {
105 return new Predicate<Identity>() {
107 public boolean apply(Identity identity) {
108 return (identity == null) ? false : identityHasChanged(oldIdentities.get(identity.getId()), identity);
113 private static boolean identityHasChanged(Identity oldIdentity, Identity newIdentity) {
114 return identityHasNewContexts(oldIdentity, newIdentity)
115 || identityHasRemovedContexts(oldIdentity, newIdentity)
116 || identityHasNewProperties(oldIdentity, newIdentity)
117 || identityHasRemovedProperties(oldIdentity, newIdentity)
118 || identityHasChangedProperties(oldIdentity, newIdentity);
121 private static boolean identityHasNewContexts(Identity oldIdentity, Identity newIdentity) {
122 return from(TO_CONTEXTS.apply(newIdentity)).anyMatch(notAContextOf(oldIdentity));
125 private static boolean identityHasRemovedContexts(Identity oldIdentity, Identity newIdentity) {
126 return from(TO_CONTEXTS.apply(oldIdentity)).anyMatch(notAContextOf(newIdentity));
129 private static boolean identityHasNewProperties(Identity oldIdentity, Identity newIdentity) {
130 return from(TO_PROPERTIES.apply(newIdentity).entrySet()).anyMatch(notAPropertyOf(oldIdentity));
133 private static boolean identityHasRemovedProperties(Identity oldIdentity, Identity newIdentity) {
134 return from(TO_PROPERTIES.apply(oldIdentity).entrySet()).anyMatch(notAPropertyOf(newIdentity));
137 private static boolean identityHasChangedProperties(Identity oldIdentity, Identity newIdentity) {
138 return from(TO_PROPERTIES.apply(oldIdentity).entrySet()).anyMatch(hasADifferentValueThanIn(newIdentity));
141 private static Predicate<Identity> containedIn(final Map<String, Identity> identities) {
142 return new Predicate<Identity>() {
144 public boolean apply(Identity identity) {
145 return (identity != null) && identities.containsKey(identity.getId());
150 private static Predicate<String> notAContextOf(final Identity identity) {
151 return new Predicate<String>() {
153 public boolean apply(String context) {
154 return (identity == null) ? false : !identity.getContexts().contains(context);
159 private static Predicate<Identity> notContainedIn(final Collection<? extends Identity> newIdentities) {
160 return new Predicate<Identity>() {
162 public boolean apply(Identity identity) {
163 return (identity == null) ? false : !newIdentities.contains(identity);
168 private static Predicate<Entry<String, String>> notAPropertyOf(final Identity identity) {
169 return new Predicate<Entry<String, String>>() {
171 public boolean apply(Entry<String, String> property) {
172 return (property == null) ? false : !identity.getProperties().containsKey(property.getKey());
177 private static Predicate<Entry<String, String>> hasADifferentValueThanIn(final Identity newIdentity) {
178 return new Predicate<Entry<String, String>>() {
180 public boolean apply(Entry<String, String> property) {
181 return (property == null) ? false : !newIdentity.getProperty(property.getKey()).equals(property.getValue());
186 private static Map<String, Identity> convertToMap(Collection<? extends Identity> identities) {
187 ImmutableMap.Builder<String, Identity> mapBuilder = ImmutableMap.builder();
188 for (Identity identity : identities) {
189 mapBuilder.put(identity.getId(), identity);
191 return mapBuilder.build();
194 public interface IdentityProcessor {
196 void processIdentity(Identity identity);