Solved some new code smells

- Return empty set instead of null FilterQuery#getSetParameters
- DateRangeFilter constructor is protected
- String constant JSONFileStorage
- String constant VersionChecker
- String constants FLOOR(, MIN(, MAX( TPSQueries

Plan/common/src/main/java/com/djrapitops/plan/storage/database/queries/filter/FilterQuery.java

@@ -20,10 +20,7 @@ import com.google.gson.Gson;
 import com.google.gson.reflect.TypeToken;
 
 import java.io.IOException;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
+import java.util.*;
 
 /**
  * Represents parameters for a single {@link Filter} parsed from the query json.
@@ -54,7 +51,7 @@ public class FilterQuery {
     }
 
     public Set<String> getSetParameters() {
-        if (parameters == null) return null;
+        if (parameters == null) return Collections.emptySet();
         return parameters.keySet();
     }
 }

Plan/common/src/main/java/com/djrapitops/plan/storage/database/queries/filter/filters/DateRangeFilter.java

@@ -32,7 +32,7 @@ public abstract class DateRangeFilter implements Filter {
     private final DBSystem dbSystem;
     private final SimpleDateFormat dateFormat;
 
-    public DateRangeFilter(DBSystem dbSystem) {
+    protected DateRangeFilter(DBSystem dbSystem) {
         this.dbSystem = dbSystem;
         this.dateFormat = new SimpleDateFormat("dd/MM/yyyy kk:mm");
     }

Plan/common/src/main/java/com/djrapitops/plan/storage/database/queries/objects/TPSQueries.java

@@ -47,32 +47,32 @@ public class TPSQueries {
     public static Query<List<TPS>> fetchTPSDataOfServer(UUID serverUUID) {
         return db -> {
             String selectLowestResolution = SELECT +
-                    "MIN(t." + DATE + ") as " + DATE + ',' +
-                    "MIN(t." + TPS + ") as " + TPS + ',' +
-                    "MAX(t." + PLAYERS_ONLINE + ") as " + PLAYERS_ONLINE + ',' +
-                    "MAX(t." + RAM_USAGE + ") as " + RAM_USAGE + ',' +
-                    "MAX(t." + CPU_USAGE + ") as " + CPU_USAGE + ',' +
-                    "MAX(t." + ENTITIES + ") as " + ENTITIES + ',' +
-                    "MAX(t." + CHUNKS + ") as " + CHUNKS + ',' +
-                    "MAX(t." + FREE_DISK + ") as " + FREE_DISK +
+                    min("t." + DATE) + " as " + DATE + ',' +
+                    min("t." + TPS) + " as " + TPS + ',' +
+                    max("t." + PLAYERS_ONLINE) + " as " + PLAYERS_ONLINE + ',' +
+                    max("t." + RAM_USAGE) + " as " + RAM_USAGE + ',' +
+                    max("t." + CPU_USAGE) + " as " + CPU_USAGE + ',' +
+                    max("t." + ENTITIES) + " as " + ENTITIES + ',' +
+                    max("t." + CHUNKS) + " as " + CHUNKS + ',' +
+                    max("t." + FREE_DISK) + " as " + FREE_DISK +
                     FROM + TABLE_NAME + " t" +
                     WHERE + SERVER_ID + "=" + ServerTable.STATEMENT_SELECT_SERVER_ID +
                     AND + DATE + "<?" +
-                    GROUP_BY + "FLOOR(" + DATE + "/?)";
+                    GROUP_BY + floor(DATE + "/?");
             String selectLowerResolution = SELECT +
-                    "MIN(t." + DATE + ") as " + DATE + ',' +
-                    "MIN(t." + TPS + ") as " + TPS + ',' +
-                    "MAX(t." + PLAYERS_ONLINE + ") as " + PLAYERS_ONLINE + ',' +
-                    "MAX(t." + RAM_USAGE + ") as " + RAM_USAGE + ',' +
-                    "MAX(t." + CPU_USAGE + ") as " + CPU_USAGE + ',' +
-                    "MAX(t." + ENTITIES + ") as " + ENTITIES + ',' +
-                    "MAX(t." + CHUNKS + ") as " + CHUNKS + ',' +
-                    "MAX(t." + FREE_DISK + ") as " + FREE_DISK +
+                    min("t." + DATE) + " as " + DATE + ',' +
+                    min("t." + TPS) + " as " + TPS + ',' +
+                    max("t." + PLAYERS_ONLINE) + " as " + PLAYERS_ONLINE + ',' +
+                    max("t." + RAM_USAGE) + " as " + RAM_USAGE + ',' +
+                    max("t." + CPU_USAGE) + " as " + CPU_USAGE + ',' +
+                    max("t." + ENTITIES) + " as " + ENTITIES + ',' +
+                    max("t." + CHUNKS) + " as " + CHUNKS + ',' +
+                    max("t." + FREE_DISK) + " as " + FREE_DISK +
                     FROM + TABLE_NAME + " t" +
                     WHERE + SERVER_ID + "=" + ServerTable.STATEMENT_SELECT_SERVER_ID +
                     AND + DATE + ">=?" +
                     AND + DATE + "<?" +
-                    GROUP_BY + "FLOOR(" + DATE + "/?)";
+                    GROUP_BY + floor(DATE + "/?");
             String selectNormalResolution = SELECT +
                     DATE + ',' + TPS + ',' + PLAYERS_ONLINE + ',' +
                     RAM_USAGE + ',' + CPU_USAGE + ',' + ENTITIES + ',' + CHUNKS + ',' + FREE_DISK +
@@ -155,11 +155,11 @@ public class TPSQueries {
     }
 
     public static Query<List<DateObj<Integer>>> fetchQueryPreviewPlayersOnline(UUID serverUUID) {
-        String sql = SELECT + "MIN(" + DATE + ") as " + DATE + ',' +
-                "MAX(" + PLAYERS_ONLINE + ") as " + PLAYERS_ONLINE +
+        String sql = SELECT + min(DATE) + " as " + DATE + ',' +
+                max(PLAYERS_ONLINE) + " as " + PLAYERS_ONLINE +
                 FROM + TABLE_NAME +
                 WHERE + SERVER_ID + "=" + ServerTable.STATEMENT_SELECT_SERVER_ID +
-                GROUP_BY + "FLOOR(" + DATE + "/?)";
+                GROUP_BY + floor(DATE + "/?");
 
         return new QueryStatement<List<DateObj<Integer>>>(sql) {
             @Override

Plan/common/src/main/java/com/djrapitops/plan/storage/database/sql/building/Sql.java

@@ -49,10 +49,21 @@ public abstract class Sql {
     public static final String IS_NULL = " IS NULL";
     public static final String IS_NOT_NULL = " IS NOT NULL";
 
+    private static final String FLOOR = "FLOOR(";
+    private static final String MIN = "MIN(";
+    private static final String MAX = "MAX(";
+    private static final String VARCHAR = "varchar(";
+
     public static String varchar(int length) {
-        return "varchar(" + length + ')';
+        return VARCHAR + length + ')';
     }
 
+    public static String floor(String expression) {return FLOOR + expression + ')';}
+
+    public static String min(String expression) {return MIN + expression + ')';}
+
+    public static String max(String expression) {return MAX + expression + ')';}
+
     /**
      * Turn day of week to epoch ms.
      * <p>

Plan/common/src/main/java/com/djrapitops/plan/storage/json/JSONFileStorage.java

@@ -44,7 +44,9 @@ public class JSONFileStorage implements JSONStorage {
     private final PluginLogger logger;
 
     private final Path jsonDirectory;
+
     private final Pattern timestampRegex = Pattern.compile(".*-([0-9]*).json");
+    private final String jsonFileExtension = ".json";
 
     @Inject
     public JSONFileStorage(PlanFiles files, PluginLogger logger) {
@@ -55,7 +57,7 @@ public class JSONFileStorage implements JSONStorage {
 
     @Override
     public StoredJSON storeJson(String identifier, String json, long timestamp) {
-        Path writingTo = jsonDirectory.resolve(identifier + '-' + timestamp + ".json");
+        Path writingTo = jsonDirectory.resolve(identifier + '-' + timestamp + jsonFileExtension);
         try {
             Files.createDirectories(jsonDirectory);
             Files.write(writingTo, json.getBytes(StandardCharsets.UTF_8), StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE);
@@ -71,7 +73,7 @@ public class JSONFileStorage implements JSONStorage {
         if (stored == null) return Optional.empty();
         for (File file : stored) {
             String fileName = file.getName();
-            if (fileName.endsWith(".json") && fileName.startsWith(identifier)) {
+            if (fileName.endsWith(jsonFileExtension) && fileName.startsWith(identifier)) {
                 return Optional.ofNullable(readStoredJSON(file));
             }
         }
@@ -99,7 +101,7 @@ public class JSONFileStorage implements JSONStorage {
 
     @Override
     public Optional<StoredJSON> fetchExactJson(String identifier, long timestamp) {
-        File found = jsonDirectory.resolve(identifier + "-" + timestamp + ".json").toFile();
+        File found = jsonDirectory.resolve(identifier + "-" + timestamp + jsonFileExtension).toFile();
         if (!found.exists()) return Optional.empty();
         return Optional.ofNullable(readStoredJSON(found));
     }
@@ -120,7 +122,7 @@ public class JSONFileStorage implements JSONStorage {
         for (File file : stored) {
             try {
                 String fileName = file.getName();
-                if (fileName.endsWith(".json") && fileName.startsWith(identifier)) {
+                if (fileName.endsWith(jsonFileExtension) && fileName.startsWith(identifier)) {
                     Matcher timestampMatch = timestampRegex.matcher(fileName);
                     if (timestampMatch.find() && timestampComparator.test(timestampMatch, timestamp)) {
                         return Optional.ofNullable(readStoredJSON(file));

Plan/common/src/main/java/com/djrapitops/plan/version/VersionChecker.java

@@ -51,6 +51,7 @@ public class VersionChecker implements SubSystem {
     private final PluginLogger logger;
     private final RunnableFactory runnableFactory;
     private final ErrorLogger errorLogger;
+    private final String downloadIconHtml = "<i class=\"fa fa-fw fa-download\"></i> ";
 
     private VersionInfo newVersionAvailable;
 
@@ -131,7 +132,7 @@ public class VersionChecker implements SubSystem {
                             "font-size: 0.95rem;" : "";
                     return "<button class=\"btn bg-white col-plan\" style=\"" + reduceFontSize +
                             "\" data-target=\"#updateModal\" data-toggle=\"modal\" type=\"button\">" +
-                            "<i class=\"fa fa-fw fa-download\"></i> " + locale.getString(PluginLang.VERSION_UPDATE) + ": " + v.getVersion().getVersionString() +
+                            downloadIconHtml + locale.getString(PluginLang.VERSION_UPDATE) + ": " + v.getVersion().getVersionString() +
                             "</button>";
                 }
         );
@@ -147,7 +148,7 @@ public class VersionChecker implements SubSystem {
         return getNewVersionAvailable()
                 .map(v -> "<div class=\"modal-header\">" +
                         "<h5 class=\"modal-title\" id=\"updateModalLabel\">" +
-                        "<i class=\"fa fa-fw fa-download\"></i> " + locale.getString(PluginLang.VERSION_UPDATE_AVAILABLE, v.getVersion().getVersionString()) +
+                        downloadIconHtml + locale.getString(PluginLang.VERSION_UPDATE_AVAILABLE, v.getVersion().getVersionString()) +
                         "</h5><button aria-label=\"Close\" class=\"close\" data-dismiss=\"modal\" type=\"button\"><span aria-hidden=\"true\">&times;</span></button>" +
                         "</div>" + // Close modal-header
                         "<div class=\"modal-body\">" +
@@ -156,7 +157,7 @@ public class VersionChecker implements SubSystem {
                         "<a class=\"btn col-plan\" href=\"" + v.getChangeLogUrl() + "\" rel=\"noopener noreferrer\" target=\"_blank\">" +
                         "<i class=\"fa fa-fw fa-list\"></i> " + locale.getString(PluginLang.VERSION_CHANGE_LOG) + "</a>" +
                         "<a class=\"btn col-plan\" href=\"" + v.getDownloadUrl() + "\" rel=\"noopener noreferrer\" target=\"_blank\">" +
-                        "<i class=\"fa fa-fw fa-download\"></i> " + locale.getString(PluginLang.VERSION_DOWNLOAD, v.getVersion().getVersionString()) + "</a>" +
+                        downloadIconHtml + locale.getString(PluginLang.VERSION_DOWNLOAD, v.getVersion().getVersionString()) + "</a>" +
                         "</div>") // Close modal-body
                 .orElse("<div class=\"modal-header\">" +
                         "<h5 class=\"modal-title\" id=\"updateModalLabel\">" +