Resets the paging3 changes of 3159 back to the (java) fragment code before.

Should be the basis for further not-so-rattling improvements.

app/src/main/java/com/keylesspalace/tusky/viewdata/NotificationViewData.java

@@ -0,0 +1,138 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
+package com.keylesspalace.tusky.viewdata;
+
+import androidx.annotation.Nullable;
+
+import com.keylesspalace.tusky.entity.Notification;
+import com.keylesspalace.tusky.entity.Report;
+import com.keylesspalace.tusky.entity.TimelineAccount;
+
+import java.util.Objects;
+
+/**
+ * Created by charlag on 12/07/2017.
+ * <p>
+ * Class to represent data required to display either a notification or a placeholder.
+ * It is either a {@link Placeholder} or a {@link Concrete}.
+ * It is modelled this way because close relationship between placeholder and concrete notification
+ * is fine in this case. Placeholder case is not modelled as a type of notification because
+ * invariants would be violated and because it would model domain incorrectly. It is preferable to
+ * {@link com.keylesspalace.tusky.util.Either} because class hierarchy is cheaper, faster and
+ * more native.
+ */
+public abstract class NotificationViewData {
+    private NotificationViewData() {
+    }
+
+    public abstract long getViewDataId();
+
+    public abstract boolean deepEquals(NotificationViewData other);
+
+    public static final class Concrete extends NotificationViewData {
+        private final Notification.Type type;
+        private final String id;
+        private final TimelineAccount account;
+        @Nullable
+        private final StatusViewData.Concrete statusViewData;
+        @Nullable
+        private final Report report;
+
+        public Concrete(Notification.Type type, String id, TimelineAccount account,
+                        @Nullable StatusViewData.Concrete statusViewData, @Nullable Report report) {
+            this.type = type;
+            this.id = id;
+            this.account = account;
+            this.statusViewData = statusViewData;
+            this.report = report;
+        }
+
+        public Notification.Type getType() {
+            return type;
+        }
+
+        public String getId() {
+            return id;
+        }
+
+        public TimelineAccount getAccount() {
+            return account;
+        }
+
+        @Nullable
+        public StatusViewData.Concrete getStatusViewData() {
+            return statusViewData;
+        }
+
+        @Nullable
+        public Report getReport() {
+            return report;
+        }
+
+        @Override
+        public long getViewDataId() {
+            return id.hashCode();
+        }
+
+        @Override
+        public boolean deepEquals(NotificationViewData o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Concrete concrete = (Concrete) o;
+            return type == concrete.type &&
+                    Objects.equals(id, concrete.id) &&
+                    account.getId().equals(concrete.account.getId()) &&
+                    (Objects.equals(statusViewData, concrete.statusViewData)) &&
+                    (Objects.equals(report, concrete.report));
+        }
+
+        @Override
+        public int hashCode() {
+
+            return Objects.hash(type, id, account, statusViewData);
+        }
+
+        public Concrete copyWithStatus(@Nullable StatusViewData.Concrete statusViewData) {
+            return new Concrete(type, id, account, statusViewData, report);
+        }
+    }
+
+    public static final class Placeholder extends NotificationViewData {
+        private final long id;
+        private final boolean isLoading;
+
+        public Placeholder(long id, boolean isLoading) {
+            this.id = id;
+            this.isLoading = isLoading;
+        }
+
+        public boolean isLoading() {
+            return isLoading;
+        }
+
+        @Override
+        public long getViewDataId() {
+            return id;
+        }
+
+        @Override
+        public boolean deepEquals(NotificationViewData other) {
+            if (!(other instanceof Placeholder)) return false;
+            Placeholder that = (Placeholder) other;
+            return isLoading == that.isLoading && id == that.id;
+        }
+    }
+}

app/src/main/java/com/keylesspalace/tusky/viewdata/NotificationViewData.kt

@@ -34,7 +34,7 @@ import com.keylesspalace.tusky.entity.Notification
 import com.keylesspalace.tusky.entity.Report
 import com.keylesspalace.tusky.entity.TimelineAccount
 
-data class NotificationViewData(
+data class NotificationViewDataX(
     val type: Notification.Type,
     val id: String,
     val account: TimelineAccount,

app/src/main/java/com/keylesspalace/tusky/viewdata/StatusViewData.kt

@@ -92,6 +92,21 @@ sealed class StatusViewData {
             this.isCollapsible = shouldTrimStatus(this.content)
         }
 
+        /** Helper for Java */
+        fun copyWithStatus(status: Status): Concrete {
+            return copy(status = status)
+        }
+
+        /** Helper for Java */
+        fun copyWithExpanded(isExpanded: Boolean): Concrete {
+            return copy(isExpanded = isExpanded)
+        }
+
+        /** Helper for Java */
+        fun copyWithShowingContent(isShowingContent: Boolean): Concrete {
+            return copy(isShowingContent = isShowingContent)
+        }
+
         /** Helper for Java */
         fun copyWithCollapsed(isCollapsed: Boolean): Concrete {
             return copy(isCollapsed = isCollapsed)