Add ability to have custom empty message, and mroe cleanup.

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/ColorAlternator.java

@@ -35,7 +35,7 @@ public class ColorAlternator {
      *
      * @return Opposite of the previous colour.
      */
-    public ChatColor get() {
+    public @NotNull ChatColor get() {
         return (switcher ^= true) ? thisColour : thatColour;
     }
 
@@ -50,8 +50,7 @@ public class ColorAlternator {
      *
      * @return {@link ColorAlternator#thisColour}.
      */
-    @NotNull
-    public ChatColor getThis() {
+    public @NotNull ChatColor getThis() {
         return thisColour;
     }
 
@@ -59,8 +58,7 @@ public class ColorAlternator {
      *
      * @return {@link ColorAlternator#thatColour}.
      */
-    @NotNull
-    public ChatColor getThat() {
+    public @NotNull ChatColor getThat() {
         return thatColour;
     }
 }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/ContentCreator.java

@@ -1,5 +1,7 @@
 package com.onarandombox.MultiverseCore.commandTools.display;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * Generate content for displaying with {@link ContentDisplay}.
  *
@@ -7,5 +9,5 @@ package com.onarandombox.MultiverseCore.commandTools.display;
  */
 @FunctionalInterface
 public interface ContentCreator<T> {
-    T generateContent();
+    @NotNull T generateContent();
 }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/ContentDisplay.java

@@ -2,6 +2,7 @@ package com.onarandombox.MultiverseCore.commandTools.display;
 
 import org.bukkit.command.CommandSender;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * Displays various types of content to sender.
@@ -15,6 +16,9 @@ public abstract class ContentDisplay<C extends ContentDisplay<?, T>, T> {
     protected ContentCreator<T> creator;
     protected ContentFilter filter = ContentFilter.EMPTY;
     protected ColorAlternator colours;
+    protected String emptyMessage = DEFAULT_EMPTY_MESSAGE;
+
+    public static final String DEFAULT_EMPTY_MESSAGE = "No matching content to display.";
 
     /**
      * Build into a runnable for showing of content.
@@ -45,48 +49,57 @@ public abstract class ContentDisplay<C extends ContentDisplay<?, T>, T> {
      */
     protected abstract @NotNull ShowRunnable<C, T> getShowRunnable();
 
-    public C withSender(CommandSender sender) {
+    public @NotNull C withSender(@NotNull CommandSender sender) {
         this.sender = sender;
         return (C) this;
     }
 
-    public C withHeader(String header) {
+    public @NotNull C withHeader(@NotNull String header) {
         this.header = header;
         return (C) this;
     }
 
-    public C withCreator(ContentCreator<T> creator) {
+    public @NotNull C withCreator(@NotNull ContentCreator<T> creator) {
         this.creator = creator;
         return (C) this;
     }
 
-    public C withFilter(ContentFilter filter) {
+    public @NotNull C withFilter(@NotNull ContentFilter filter) {
         this.filter = filter;
         return (C) this;
     }
 
-    public C withColors(ColorAlternator colours) {
+    public @NotNull C withColors(@NotNull ColorAlternator colours) {
         this.colours = colours;
         return (C) this;
     }
 
-    public CommandSender getSender() {
+    public @NotNull C withEmptyMessage(@NotNull String emptyMessage) {
+        this.emptyMessage = emptyMessage;
+        return (C) this;
+    }
+
+    public @NotNull CommandSender getSender() {
         return sender;
     }
 
-    public String getHeader() {
+    public @Nullable String getHeader() {
         return header;
     }
 
-    public ContentCreator<T> getCreator() {
+    public @NotNull ContentCreator<T> getCreator() {
         return creator;
     }
 
-    public ContentFilter getFilter() {
+    public @NotNull ContentFilter getFilter() {
         return filter;
     }
 
-    public ColorAlternator getColours() {
+    public @NotNull ColorAlternator getColours() {
         return colours;
     }
+
+    public @NotNull String getEmptyMessage() {
+        return emptyMessage;
+    }
 }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/ContentFilter.java

@@ -94,13 +94,11 @@ public class ContentFilter {
         return filterPattern != null;
     }
 
-    @Nullable
-    public String getString() {
+    public @Nullable String getString() {
         return filterString;
     }
 
-    @Nullable
-    public Pattern getPattern() {
+    public @Nullable Pattern getPattern() {
         return filterPattern;
     }
 
@@ -113,8 +111,7 @@ public class ContentFilter {
      *
      * @return formatted filter string.
      */
-    @NotNull
-    public String getFormattedString() {
+    public @NotNull String getFormattedString() {
         return String.format("%sFilter: '%s'%s", ChatColor.ITALIC, filterString, ChatColor.RESET);
     }
 

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/ShowRunnable.java

@@ -27,10 +27,6 @@ public abstract class ShowRunnable<D extends ContentDisplay<?, T>, T> extends Bu
         if (!validateContent()) {
             return;
         }
-        if (!hasContentToShow()) {
-            this.display.getSender().sendMessage("No matching content to display.");
-            return;
-        }
         display();
     }
 
@@ -39,6 +35,10 @@ public abstract class ShowRunnable<D extends ContentDisplay<?, T>, T> extends Bu
      */
     protected void display() {
         showHeader();
+        if (!hasContentToShow()) {
+            this.display.getSender().sendMessage(this.display.getEmptyMessage());
+            return;
+        }
         showContent();
     }
 

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/inline/KeyValueDisplay.java

@@ -22,7 +22,7 @@ public class KeyValueDisplay extends ContentDisplay<KeyValueDisplay, Map<String,
         return new ShowKeyValue(this);
     }
 
-    public KeyValueDisplay withOperator(String operator) {
+    public @NotNull KeyValueDisplay withOperator(@NotNull String operator) {
         this.operator = operator;
         return this;
     }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/inline/ShowInline.java

@@ -2,12 +2,13 @@ package com.onarandombox.MultiverseCore.commandTools.display.inline;
 
 import com.onarandombox.MultiverseCore.commandTools.display.ContentDisplay;
 import com.onarandombox.MultiverseCore.commandTools.display.ShowRunnable;
+import org.jetbrains.annotations.NotNull;
 
 public abstract class ShowInline<D extends ContentDisplay<?, T>, T> extends ShowRunnable<D, T> {
 
     protected final StringBuilder contentBuilder;
 
-    public ShowInline(D display) {
+    public ShowInline(@NotNull D display) {
         super(display);
         this.contentBuilder = new StringBuilder();
     }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/inline/ShowKeyValue.java

@@ -2,6 +2,7 @@ package com.onarandombox.MultiverseCore.commandTools.display.inline;
 
 import com.onarandombox.MultiverseCore.commandTools.display.ContentFilter;
 import org.bukkit.ChatColor;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Map;
 
@@ -9,7 +10,7 @@ public class ShowKeyValue extends ShowInline<KeyValueDisplay, Map<String, Object
 
     private final StringBuilder contentBuilder;
 
-    public ShowKeyValue(KeyValueDisplay display) {
+    public ShowKeyValue(@NotNull KeyValueDisplay display) {
         super(display);
         this.contentBuilder = new StringBuilder();
     }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/inline/ShowList.java

@@ -1,10 +1,12 @@
 package com.onarandombox.MultiverseCore.commandTools.display.inline;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.List;
 
 public class ShowList extends ShowInline<ListDisplay, List<String>> {
 
-    public ShowList(ListDisplay display) {
+    public ShowList(@NotNull ListDisplay display) {
         super(display);
     }
 

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/page/PageDisplay.java

@@ -38,18 +38,18 @@ public class PageDisplay extends ContentDisplay<PageDisplay, List<String>> {
                 : new ShowSelectedPage(this);
     }
 
-    public PageDisplay withPageFilter(PageFilter pageFilter) {
+    public @NotNull PageDisplay withPageFilter(@NotNull PageFilter pageFilter) {
         this.pageToShow = pageFilter.getPage();
         this.filter = pageFilter.getFilter();
         return this;
     }
 
-    public PageDisplay withPage(int pageToShow) {
+    public @NotNull PageDisplay withPage(int pageToShow) {
         this.pageToShow = pageToShow;
         return this;
     }
 
-    public PageDisplay withLinesPerPage(int contentLinesPerPage) {
+    public @NotNull PageDisplay withLinesPerPage(int contentLinesPerPage) {
         this.contentLinesPerPage = contentLinesPerPage;
         return this;
     }

src/main/java/com/onarandombox/MultiverseCore/commandTools/display/page/ShowSelectedPage.java

@@ -24,6 +24,13 @@ public class ShowSelectedPage extends ShowPage {
         doEndPadding();
     }
 
+    private void doEndPadding() {
+        IntStream.range(0, this.display.getContentLinesPerPage() - contentToShowIndex.size())
+                .unordered()
+                .mapToObj(i -> " ")
+                .forEach(this.display.getSender()::sendMessage);
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -100,11 +107,4 @@ public class ShowSelectedPage extends ShowPage {
                 ? String.format("[ Page %s of %s, %s ]", this.display.getPageToShow(), totalPages, filter.getFormattedString())
                 : String.format("[ Page %s of %s ]", this.display.getPageToShow(), totalPages);
     }
-
-    private void doEndPadding() {
-        IntStream.range(0, this.display.getContentLinesPerPage() - contentToShowIndex.size())
-                .unordered()
-                .mapToObj(i -> " ")
-                .forEach(this.display.getSender()::sendMessage);
-    }
 }

src/main/java/com/onarandombox/MultiverseCore/commands/WhoCommand.java

@@ -82,6 +82,7 @@ public class WhoCommand extends MultiverseCommand {
                 .withHeader(String.format("%s===[ Players in %s%s ]===", ChatColor.AQUA, world.getColoredWorldString(), ChatColor.AQUA))
                 .withCreator(buildPlayerList(world, player))
                 .withFilter(filter)
+                .withEmptyMessage(String.format("%sNo players found.", ChatColor.GRAY))
                 .build()
                 .runTaskAsynchronously(this.plugin);
     }
@@ -92,16 +93,10 @@ public class WhoCommand extends MultiverseCommand {
 
         return () -> {
             Set<Player> visiblePlayers = getVisiblePlayers(player);
-            List<String> players = world.getCBWorld().getPlayers().stream()
+            return world.getCBWorld().getPlayers().stream()
                 .filter(visiblePlayers::contains)
                 .map(Player::getDisplayName)
                 .collect(Collectors.toList());
-
-            if (players.isEmpty()) {
-                players.add(String.format("%sNo players found.", ChatColor.GRAY));
-            }
-
-            return players;
         };
     }