Cache download type refactoring (for listing auto-refreshes)

src/main/java/org/quantumbadger/redreader/activities/CaptchaActivity.java

@@ -34,6 +34,7 @@
 import org.quantumbadger.redreader.account.RedditAccountManager;
 import org.quantumbadger.redreader.cache.CacheManager;
 import org.quantumbadger.redreader.cache.CacheRequest;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategyAlways;
 import org.quantumbadger.redreader.common.AndroidApi;
 import org.quantumbadger.redreader.common.Constants;
 import org.quantumbadger.redreader.common.General;
@@ -72,7 +73,7 @@ protected void onSuccess(final String captchaId) {
 				final URI captchaUrl = General.uriFromString("https://reddit.com/captcha/" + captchaId);
 
 				cm.makeRequest(new CacheRequest(captchaUrl, RedditAccountManager.getAnon(), null, Constants.Priority.CAPTCHA,
-						0, CacheRequest.DOWNLOAD_FORCE, Constants.FileType.CAPTCHA,
+						0, DownloadStrategyAlways.INSTANCE, Constants.FileType.CAPTCHA,
 						CacheRequest.DOWNLOAD_QUEUE_IMMEDIATE, false, true, CaptchaActivity.this) {
 					@Override
 					protected void onCallbackException(Throwable t) {

src/main/java/org/quantumbadger/redreader/activities/ImageViewActivity.java

@@ -42,6 +42,7 @@
 import org.quantumbadger.redreader.account.RedditAccountManager;
 import org.quantumbadger.redreader.cache.CacheManager;
 import org.quantumbadger.redreader.cache.CacheRequest;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategyIfNotCached;
 import org.quantumbadger.redreader.common.AndroidApi;
 import org.quantumbadger.redreader.common.Constants;
 import org.quantumbadger.redreader.common.General;
@@ -217,7 +218,7 @@ public void onSuccess(final ImageInfo info) {
 								null,
 								Constants.Priority.IMAGE_VIEW,
 								0,
-								CacheRequest.DOWNLOAD_IF_NECESSARY,
+								DownloadStrategyIfNotCached.INSTANCE,
 								Constants.FileType.IMAGE,
 								CacheRequest.DOWNLOAD_QUEUE_IMMEDIATE,
 								false,

src/main/java/org/quantumbadger/redreader/activities/ImgurUploadActivity.java

@@ -37,6 +37,7 @@
 import org.quantumbadger.redreader.account.RedditAccountManager;
 import org.quantumbadger.redreader.cache.CacheManager;
 import org.quantumbadger.redreader.cache.CacheRequest;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategyAlways;
 import org.quantumbadger.redreader.common.AndroidApi;
 import org.quantumbadger.redreader.common.Constants;
 import org.quantumbadger.redreader.common.General;
@@ -280,7 +281,7 @@ private void uploadImage() {
 				null,
 				Constants.Priority.API_ACTION,
 				0,
-				CacheRequest.DOWNLOAD_FORCE,
+				DownloadStrategyAlways.INSTANCE,
 				Constants.FileType.NOCACHE,
 				CacheRequest.DOWNLOAD_QUEUE_IMGUR_API,
 				true,

src/main/java/org/quantumbadger/redreader/activities/InboxListingActivity.java

@@ -36,6 +36,7 @@
 import org.quantumbadger.redreader.adapters.GroupedRecyclerViewAdapter;
 import org.quantumbadger.redreader.cache.CacheManager;
 import org.quantumbadger.redreader.cache.CacheRequest;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategyAlways;
 import org.quantumbadger.redreader.common.AndroidApi;
 import org.quantumbadger.redreader.common.Constants;
 import org.quantumbadger.redreader.common.General;
@@ -208,7 +209,7 @@ private void makeFirstRequest(final Context context) {
 
 		// TODO parameterise limit
 		request = new CacheRequest(url, user, null, Constants.Priority.API_INBOX_LIST, 0,
-				CacheRequest.DOWNLOAD_FORCE, Constants.FileType.INBOX_LIST,
+				DownloadStrategyAlways.INSTANCE, Constants.FileType.INBOX_LIST,
 				CacheRequest.DOWNLOAD_QUEUE_REDDIT_API, true, true, context) {
 
 			@Override

src/main/java/org/quantumbadger/redreader/activities/MoreCommentsListingActivity.java

@@ -29,7 +29,6 @@
 import org.quantumbadger.redreader.R;
 import org.quantumbadger.redreader.account.RedditAccountChangeListener;
 import org.quantumbadger.redreader.account.RedditAccountManager;
-import org.quantumbadger.redreader.cache.CacheRequest;
 import org.quantumbadger.redreader.common.DialogUtils;
 import org.quantumbadger.redreader.common.General;
 import org.quantumbadger.redreader.common.LinkHandler;
@@ -125,7 +124,7 @@ protected void doRefresh(final RefreshableFragment which, final boolean force, f
 				mUrls,
 				null,
 				mSearchString,
-				force ? CacheRequest.DOWNLOAD_FORCE : CacheRequest.DOWNLOAD_IF_NECESSARY);
+				force);
 
 		mPane.removeAllViews();
 

src/main/java/org/quantumbadger/redreader/adapters/AlbumAdapter.java

@@ -28,6 +28,7 @@
 import org.quantumbadger.redreader.account.RedditAccountManager;
 import org.quantumbadger.redreader.cache.CacheManager;
 import org.quantumbadger.redreader.cache.CacheRequest;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategyIfNotCached;
 import org.quantumbadger.redreader.common.AndroidApi;
 import org.quantumbadger.redreader.common.Constants;
 import org.quantumbadger.redreader.common.General;
@@ -114,17 +115,17 @@ public void onBindViewHolder(final VH2TextIcon vh, final int position) {
 			vh.text2.setVisibility(View.VISIBLE);
 
 			CacheManager.getInstance(activity).makeRequest(new CacheRequest(
-				General.uriFromString(imageInfo.urlBigSquare),
-				RedditAccountManager.getAnon(),
-				null,
-				Constants.Priority.THUMBNAIL,
-				position,
-				CacheRequest.DOWNLOAD_IF_NECESSARY,
-				Constants.FileType.THUMBNAIL,
-				CacheRequest.DOWNLOAD_QUEUE_IMMEDIATE,
-				false,
-				false,
-				activity
+					General.uriFromString(imageInfo.urlBigSquare),
+					RedditAccountManager.getAnon(),
+					null,
+					Constants.Priority.THUMBNAIL,
+					position,
+					DownloadStrategyIfNotCached.INSTANCE,
+					Constants.FileType.THUMBNAIL,
+					CacheRequest.DOWNLOAD_QUEUE_IMMEDIATE,
+					false,
+					false,
+					activity
 			) {
 				@Override
 				protected void onCallbackException(final Throwable t) {

src/main/java/org/quantumbadger/redreader/cache/CacheManager.java

@@ -353,45 +353,44 @@ public void run() {
 		private void handleRequest(final CacheRequest request) {
 
 			if(request.url == null) {
-				request.notifyFailure(CacheRequest.REQUEST_FAILURE_MALFORMED_URL, new NullPointerException("URL was null"), null, "URL was null");
+				request.notifyFailure(
+						CacheRequest.REQUEST_FAILURE_MALFORMED_URL,
+						new NullPointerException("URL was null"),
+						null,
+						"URL was null");
 				return;
 			}
 
-			switch(request.downloadType) {
+			if(request.downloadStrategy.shouldDownloadWithoutCheckingCache()) {
+				queueDownload(request);
 
-				case CacheRequest.DOWNLOAD_NEVER: {
+			} else {
 
-					final LinkedList<CacheEntry> result = dbManager.select(request.url, request.user.username, request.requestSession);
+				final LinkedList<CacheEntry> result = dbManager.select(request.url, request.user.username, request.requestSession);
 
-					if(result.size() == 0) {
-						request.notifyFailure(CacheRequest.REQUEST_FAILURE_CACHE_MISS, null, null, "Could not find this data in the cache");
+				if(result.isEmpty()) {
+
+					if(request.downloadStrategy.shouldDownloadIfNotCached()) {
+						queueDownload(request);
 
 					} else {
-						final CacheEntry entry = mostRecentFromList(result);
-						handleCacheEntryFound(entry, request);
+						request.notifyFailure(
+								CacheRequest.REQUEST_FAILURE_CACHE_MISS,
+								null,
+								null,
+								"Could not find this data in the cache");
 					}
 
-					break;
-				}
-
-				case CacheRequest.DOWNLOAD_IF_NECESSARY: {
+				} else {
 
-					final LinkedList<CacheEntry> result = dbManager.select(request.url, request.user.username, request.requestSession);
+					final CacheEntry entry = mostRecentFromList(result);
 
-					if(result.size() == 0) {
+					if(request.downloadStrategy.shouldDownloadIfCacheEntryFound(entry)) {
 						queueDownload(request);
-
 					} else {
-						final CacheEntry entry = mostRecentFromList(result);
 						handleCacheEntryFound(entry, request);
 					}
-
-					break;
 				}
-
-				case CacheRequest.DOWNLOAD_FORCE:
-					queueDownload(request);
-					break;
 			}
 		}
 
@@ -424,11 +423,13 @@ private void handleCacheEntryFound(final CacheEntry entry, final CacheRequest re
 
 			if(cacheFile == null) {
 
-				if(request.downloadType == CacheRequest.DOWNLOAD_IF_NECESSARY) {
-					queueDownload(request);
-				} else {
-					request.notifyFailure(CacheRequest.REQUEST_FAILURE_STORAGE, null, null, "A cache entry was found in the database, but the actual data couldn't be found. Press refresh to download the content again.");
-				}
+				request.notifyFailure(
+						CacheRequest.REQUEST_FAILURE_STORAGE,
+						null,
+						null,
+						"A cache entry was found in the database, but the actual data couldn't be found. Press refresh to download the content again.");
+
+				dbManager.delete(entry.id);
 
 				return;
 			}
@@ -481,11 +482,7 @@ public void run() {
 								existingCacheFile.delete();
 							}
 
-							if(request.downloadType == CacheRequest.DOWNLOAD_IF_NECESSARY) {
-								queueDownload(request);
-							} else {
-								request.notifyFailure(CacheRequest.REQUEST_FAILURE_PARSE, t, null, "Error parsing the JSON stream");
-							}
+							request.notifyFailure(CacheRequest.REQUEST_FAILURE_PARSE, t, null, "Error parsing the JSON stream");
 
 							return;
 						}

src/main/java/org/quantumbadger/redreader/cache/CacheRequest.java

@@ -19,9 +19,11 @@
 
 import android.content.Context;
 import android.support.annotation.IntDef;
+import android.support.annotation.NonNull;
 import android.util.Log;
 import org.quantumbadger.redreader.account.RedditAccount;
 import org.quantumbadger.redreader.activities.BugReportActivity;
+import org.quantumbadger.redreader.cache.downloadstrategy.DownloadStrategy;
 import org.quantumbadger.redreader.common.PrioritisedCachedThreadPool;
 import org.quantumbadger.redreader.common.RRError;
 import org.quantumbadger.redreader.http.HTTPBackend;
@@ -57,10 +59,6 @@ public abstract class CacheRequest implements Comparable<CacheRequest> {
 	public static final int REQUEST_FAILURE_UPLOAD_FAIL_IMGUR = 10;
 	public static final int REQUEST_FAILURE_CACHE_DIR_DOES_NOT_EXIST = 11;
 
-	@IntDef({DOWNLOAD_NEVER, DOWNLOAD_IF_NECESSARY, DOWNLOAD_FORCE})
-	@Retention(RetentionPolicy.SOURCE)
-	public @interface DownloadType {}
-
 	@IntDef({DOWNLOAD_QUEUE_REDDIT_API, DOWNLOAD_QUEUE_IMGUR_API, DOWNLOAD_QUEUE_IMMEDIATE,
 		DOWNLOAD_QUEUE_IMAGE_PRECACHE})
 	@Retention(RetentionPolicy.SOURCE)
@@ -82,7 +80,7 @@ public abstract class CacheRequest implements Comparable<CacheRequest> {
 	public final int priority;
 	public final int listId;
 
-	public final @DownloadType int downloadType;
+	@NonNull public final DownloadStrategy downloadStrategy;
 
 	public final int fileType;
 
@@ -116,17 +114,17 @@ public synchronized void cancel() {
 	}
 
 	protected CacheRequest(final URI url, final RedditAccount user, final UUID requestSession, final int priority,
-						   final int listId, final @DownloadType int downloadType, final int fileType,
+						   final int listId, @NonNull final DownloadStrategy downloadStrategy, final int fileType,
 						   final @DownloadQueueType int queueType, final boolean isJson, final boolean cancelExisting,
 						   final Context context) {
 
-		this(url, user, requestSession, priority, listId, downloadType, fileType, queueType, isJson, null,
+		this(url, user, requestSession, priority, listId, downloadStrategy, fileType, queueType, isJson, null,
 			true, cancelExisting, context);
 	}
 
 	// TODO remove this huge constructor, make mutable
 	protected CacheRequest(final URI url, final RedditAccount user, final UUID requestSession, final int priority,
-						   final int listId, final @DownloadType int downloadType, final int fileType,
+						   final int listId, @NonNull final DownloadStrategy downloadStrategy, final int fileType,
 						   final @DownloadQueueType int queueType, final boolean isJson, final List<HTTPBackend.PostField> postFields,
 						   final boolean cache, final boolean cancelExisting, final Context context) {
 
@@ -135,8 +133,8 @@ protected CacheRequest(final URI url, final RedditAccount user, final UUID reque
 		if (user == null)
 			throw new NullPointerException("User was null - set to empty string for anonymous");
 
-		if (downloadType != DOWNLOAD_FORCE && postFields != null)
-			throw new IllegalArgumentException("Download type must be forced for POST requests");
+		if (!downloadStrategy.shouldDownloadWithoutCheckingCache() && postFields != null)
+			throw new IllegalArgumentException("Should not perform cache lookup for POST requests");
 
 		if (!isJson && postFields != null)
 			throw new IllegalArgumentException("POST requests must be for JSON values");
@@ -152,7 +150,7 @@ protected CacheRequest(final URI url, final RedditAccount user, final UUID reque
 		this.requestSession = requestSession;
 		this.priority = priority;
 		this.listId = listId;
-		this.downloadType = downloadType;
+		this.downloadStrategy = downloadStrategy;
 		this.fileType = fileType;
 		this.queueType = queueType;
 		this.isJson = isJson;

src/main/java/org/quantumbadger/redreader/cache/downloadstrategy/DownloadStrategy.java

@@ -0,0 +1,29 @@
+/*******************************************************************************
+ * This file is part of RedReader.
+ *
+ * RedReader 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.
+ *
+ * RedReader 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 RedReader.  If not, see <http://www.gnu.org/licenses/>.
+ ******************************************************************************/
+
+package org.quantumbadger.redreader.cache.downloadstrategy;
+
+import org.quantumbadger.redreader.cache.CacheEntry;
+
+public interface DownloadStrategy {
+
+	boolean shouldDownloadWithoutCheckingCache();
+
+	boolean shouldDownloadIfCacheEntryFound(final CacheEntry entry);
+
+	boolean shouldDownloadIfNotCached();
+}

src/main/java/org/quantumbadger/redreader/cache/downloadstrategy/DownloadStrategyAlways.java

@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * This file is part of RedReader.
+ *
+ * RedReader 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.
+ *
+ * RedReader 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 RedReader.  If not, see <http://www.gnu.org/licenses/>.
+ ******************************************************************************/
+
+package org.quantumbadger.redreader.cache.downloadstrategy;
+
+import org.quantumbadger.redreader.cache.CacheEntry;
+
+public class DownloadStrategyAlways implements DownloadStrategy {
+
+	public static final DownloadStrategyAlways INSTANCE = new DownloadStrategyAlways();
+
+	private DownloadStrategyAlways() {}
+
+	@Override
+	public boolean shouldDownloadWithoutCheckingCache() {
+		return true;
+	}
+
+	@Override
+	public boolean shouldDownloadIfCacheEntryFound(final CacheEntry entry) {
+		// Should never get here
+		return true;
+	}
+
+	@Override
+	public boolean shouldDownloadIfNotCached() {
+		// Should never get here
+		return true;
+	}
+}