Merge pull request #2667 from Multiverse/content-display-improvements

A few tweaks to ContentDisplay and friends.

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

@@ -8,11 +8,9 @@
 package com.onarandombox.MultiverseCore.commands;
 
 import com.onarandombox.MultiverseCore.MultiverseCore;
-import com.onarandombox.MultiverseCore.api.MultiverseWorld;
+import com.onarandombox.MultiverseCore.display.ColorAlternator;
-import com.onarandombox.MultiverseCore.displaytools.ColorAlternator;
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
-import com.onarandombox.MultiverseCore.displaytools.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.settings.MapDisplaySettings;
-import com.onarandombox.MultiverseCore.displaytools.DisplayHandlers;
-import com.onarandombox.MultiverseCore.displaytools.DisplaySettings;
 import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import org.bukkit.GameRule;
@@ -21,7 +19,6 @@ import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.permissions.PermissionDefault;
 
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -76,14 +73,11 @@ public class GamerulesCommand extends MultiverseCommand {
             }
         }
 
-        new ContentDisplay.Builder<Map<String, Object>>()
+        ContentDisplay.forContent(getGameRuleMap(world))
-                .sender(sender)
                 .header("=== Gamerules for %s%s%s ===", ChatColor.AQUA, world.getName(), ChatColor.WHITE)
-                .contents(getGameRuleMap(world))
-                .displayHandler(DisplayHandlers.INLINE_MAP)
                 .colorTool(ColorAlternator.with(ChatColor.GREEN, ChatColor.GOLD))
-                .setting(DisplaySettings.OPERATOR, ": ")
+                .setting(MapDisplaySettings.OPERATOR, ": ")
-                .display();
+                .show(sender);
     }
 
     private Map<String, Object> getGameRuleMap(World world) {

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

@@ -7,14 +7,13 @@
 
 package com.onarandombox.MultiverseCore.commands;
 
-import com.dumptruckman.minecraft.util.Logging;
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.api.MultiverseWorld;
-import com.onarandombox.MultiverseCore.displaytools.ColorAlternator;
+import com.onarandombox.MultiverseCore.display.ColorAlternator;
-import com.onarandombox.MultiverseCore.displaytools.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
-import com.onarandombox.MultiverseCore.displaytools.ContentFilter;
+import com.onarandombox.MultiverseCore.display.ContentFilter;
-import com.onarandombox.MultiverseCore.displaytools.DisplayHandlers;
+import com.onarandombox.MultiverseCore.display.DisplayHandlers;
-import com.onarandombox.MultiverseCore.displaytools.DisplaySettings;
+import com.onarandombox.MultiverseCore.display.settings.PagedDisplaySettings;
 import org.bukkit.ChatColor;
 import org.bukkit.World;
 import org.bukkit.command.CommandSender;
@@ -22,9 +21,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.permissions.PermissionDefault;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -68,18 +65,16 @@ public class ListCommand extends MultiverseCommand {
             }
         }
 
-        new ContentDisplay.Builder<Collection<String>>()
+        ContentDisplay.forContent(getListContents(sender))
-                .sender(sender)
                 .header("%s====[ Multiverse World List ]====", ChatColor.GOLD)
-                .contents(getListContents(sender))
                 .displayHandler(DisplayHandlers.PAGE_LIST)
                 .colorTool(ColorAlternator.with(ChatColor.AQUA, ChatColor.GOLD))
                 .filter(filter)
-                .setting(DisplaySettings.SHOW_PAGE, page)
+                .setting(PagedDisplaySettings.SHOW_PAGE, page)
-                .display();
+                .show(sender);
     }
 
-    private List<String> getListContents(@NotNull CommandSender sender) {
+    private Collection<String> getListContents(@NotNull CommandSender sender) {
         Player player = (sender instanceof Player) ? (Player) sender : null;
 
         List<String> worldList = this.plugin.getMVWorldManager().getMVWorlds().stream()

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

@@ -1,4 +1,4 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display;
 
 import org.bukkit.ChatColor;
 import org.jetbrains.annotations.NotNull;

src/main/java/com/onarandombox/MultiverseCore/display/ColorTool.java

@@ -1,10 +1,11 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display;
 
 import org.bukkit.ChatColor;
 
 /**
  * Tools to allow customisation.
  */
+@FunctionalInterface
 public interface ColorTool {
 
     /**

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

@@ -1,9 +1,9 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display;
 
+import com.onarandombox.MultiverseCore.display.settings.DisplaySetting;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import java.util.Collection;
 import java.util.Map;
@@ -19,39 +19,66 @@ public class ContentDisplay<T> {
 
     public static final String LINE_BREAK = "%br%";
 
-    private CommandSender sender;
+    /**
+     * Creates a ContentDisplay.Builder for the given content.
+     *
+     * @param content The content to be displayed.
+     * @param <T> The type of the content which can be inferred.
+     * @return A new Builder.
+     */
+    public static <T> Builder<T> forContent(T content) {
+        return new Builder<>(content);
+    }
+
+    /**
+     * Creates a ContentDisplay.Builder for the given collection of content.
+     *
+     * @param content The content to be displayed.
+     * @return A new Builder.
+     */
+    public static Builder<Collection<String>> forContent(Collection<String> content) {
+        return new Builder<>(content).displayHandler(DisplayHandlers.LIST);
+    }
+
+    /**
+     * Creates a ContentDisplay.Builder for the given map of content.
+     *
+     * @param content The content to be displayed.
+     * @return A new Builder.
+     */
+    public static Builder<Map<String, Object>> forContent(Map<String, Object> content) {
+        return new Builder<>(content).displayHandler(DisplayHandlers.INLINE_MAP);
+    }
+
+    private final T contents;
+
     private String header;
-    private T contents;
     private String emptyMessage = "No matching content to display.";
     private DisplayHandler<T> displayHandler;
     private ColorTool colorTool = ColorTool.DEFAULT;
     private ContentFilter filter = ContentFilter.DEFAULT;
     private final Map<DisplaySetting<?>, Object> settingsMap = new WeakHashMap<>();
 
-    private ContentDisplay() { }
+    private ContentDisplay(T contents) {
+        this.contents = contents;
+    }
 
     /**
      * Do the actual displaying of contents to the sender.
+     *
+     * @param sender The CommandSender to show the display to.
      */
-    public void send() {
+    public void show(@NotNull CommandSender sender) {
         Collection<String> formattedContent;
         try {
-            formattedContent = (this.contents == null) ? null : this.displayHandler.format(this);
+            formattedContent = (this.contents == null) ? null : this.displayHandler.format(sender, this);
         } catch (DisplayFormatException e) {
-            this.sender.sendMessage(String.format("%sError: %s", ChatColor.RED, e.getMessage()));
+            sender.sendMessage(String.format("%sError: %s", ChatColor.RED, e.getMessage()));
             return;
         }
-        this.displayHandler.sendHeader(this);
+        this.displayHandler.sendHeader(sender, this);
-        this.displayHandler.sendSubHeader(this);
+        this.displayHandler.sendSubHeader(sender, this);
-        this.displayHandler.sendBody(this, formattedContent);
+        this.displayHandler.sendBody(sender, this, formattedContent);
-    }
-
-    /**
-     * @return Gets the target sender.
-     */
-    @NotNull
-    public CommandSender getSender() {
-        return sender;
     }
 
     /**
@@ -138,20 +165,8 @@ public class ContentDisplay<T> {
 
         private final ContentDisplay<T> display;
 
-        public Builder() {
+        private Builder(T content) {
-            this.display = new ContentDisplay<>();
+            this.display = new ContentDisplay<>(content);
-        }
-
-        /**
-         * Sets target sender to display message to. <b>Required.</b>
-         *
-         * @param sender The target sender.
-         * @return The builder.
-         */
-        @NotNull
-        public Builder<T> sender(@NotNull CommandSender sender) {
-            this.display.sender = sender;
-            return this;
         }
 
         /**
@@ -167,18 +182,6 @@ public class ContentDisplay<T> {
             return this;
         }
 
-        /**
-         * Sets content to be displayed.
-         *
-         * @param contents  The contents.
-         * @return The builder.
-         */
-        @NotNull
-        public Builder<T> contents(@Nullable T contents) {
-            this.display.contents = contents;
-            return this;
-        }
-
         /**
          * Sets the message to show when no content is available for display.
          *
@@ -249,16 +252,17 @@ public class ContentDisplay<T> {
          */
         @NotNull
         public ContentDisplay<T> build() {
-            Objects.requireNonNull(this.display.sender);
             Objects.requireNonNull(this.display.displayHandler);
             return this.display;
         }
 
         /**
-         * Build and send the contents to the sender.
+         * Build and show the content to the sender.
+         *
+         * @param sender The CommandSender to show the display to.
          */
-        public void display() {
+        public void show(CommandSender sender) {
-            this.build().send();
+            this.build().show(sender);
         }
     }
 }

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

@@ -1,4 +1,4 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display;
 
 import com.dumptruckman.minecraft.util.Logging;
 import org.bukkit.ChatColor;

src/main/java/com/onarandombox/MultiverseCore/display/DisplayFormatException.java

@@ -1,4 +1,4 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display;
 
 /**
  * Thrown when an issue occur while formatting content.

src/main/java/com/onarandombox/MultiverseCore/display/DisplayHandler.java

@@ -0,0 +1,68 @@
+package com.onarandombox.MultiverseCore.display;
+
+import com.google.common.base.Strings;
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+
+/**
+ * Handles the formatting and sending of all content by the {@link ContentDisplay}.
+ *
+ * @param <T>   Type of content to display.
+ */
+@FunctionalInterface
+public interface DisplayHandler<T> {
+
+    /**
+     * Formats the raw content into a {@link Collection<String>} for displaying to the given sender.
+     *
+     * @param sender The {@link CommandSender} who will the content will be displayed to.
+     * @param display The responsible {@link ContentDisplay}.
+     * @return The formatted content.
+     * @throws DisplayFormatException Issue occurred while formatting content. E.g. invalid page.
+     */
+    Collection<String> format(@NotNull CommandSender sender, @NotNull ContentDisplay<T> display)
+            throws DisplayFormatException;
+
+    /**
+     * Sends the header.
+     *
+     * @param sender The {@link CommandSender} who will the header will be displayed to.
+     * @param display The responsible {@link ContentDisplay}.
+     */
+    default void sendHeader(@NotNull CommandSender sender, @NotNull ContentDisplay<T> display) {
+        if (!Strings.isNullOrEmpty(display.getHeader())) {
+            sender.sendMessage(display.getHeader());
+        }
+    }
+
+    /**
+     * Sends info such as filter and page.
+     *
+     * @param sender The {@link CommandSender} who will the sub header will be displayed to.
+     * @param display The responsible {@link ContentDisplay}.
+     */
+    default void sendSubHeader(@NotNull CommandSender sender, @NotNull ContentDisplay<T> display) {
+        if (display.getFilter().hasFilter()) {
+            sender.sendMessage(String.format("%s[ %s ]", ChatColor.GRAY, display.getFilter().getFormattedString()));
+        }
+    }
+
+    /**
+     * Sends the content.
+     *
+     * @param sender The {@link CommandSender} who will the body will be displayed to.
+     * @param display The responsible {@link ContentDisplay}.
+     * @param formattedContent The content after being formatted by {@link #format(CommandSender, ContentDisplay)}
+     */
+    default void sendBody(@NotNull CommandSender sender, @NotNull ContentDisplay<T> display,
+                          Collection<String> formattedContent) {
+        if (formattedContent == null || formattedContent.size() == 0) {
+            sender.sendMessage(display.getEmptyMessage());
+            return;
+        }
+        sender.sendMessage(formattedContent.toArray(new String[0]));
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/display/DisplayHandlers.java

@@ -0,0 +1,47 @@
+package com.onarandombox.MultiverseCore.display;
+
+import com.onarandombox.MultiverseCore.display.handlers.InlineListDisplayHandler;
+import com.onarandombox.MultiverseCore.display.handlers.InlineMapDisplayHandler;
+import com.onarandombox.MultiverseCore.display.handlers.ListDisplayHandler;
+import com.onarandombox.MultiverseCore.display.handlers.PagedListDisplayHandler;
+import com.onarandombox.MultiverseCore.display.settings.InlineDisplaySettings;
+import com.onarandombox.MultiverseCore.display.settings.PagedDisplaySettings;
+import com.onarandombox.MultiverseCore.display.settings.MapDisplaySettings;
+
+import java.util.Collection;
+import java.util.Map;
+
+/**
+ * Various implementations of {@link DisplayHandler}.
+ */
+public class DisplayHandlers {
+
+    /**
+     * Standard list display.
+     *
+     * Supported settings: none.
+     */
+    public static final DisplayHandler<Collection<String>> LIST = new ListDisplayHandler();
+
+    /**
+     * List display with paging.
+     *
+     * Supported settings: {@link PagedDisplaySettings#SHOW_PAGE}, {@link PagedDisplaySettings#LINES_PER_PAGE},
+     * {@link PagedDisplaySettings#PAGE_IN_CONSOLE}, {@link PagedDisplaySettings#DO_END_PADDING}.
+     */
+    public static final DisplayHandler<Collection<String>> PAGE_LIST = new PagedListDisplayHandler();
+
+    /**
+     * Display a list inline.
+     *
+     * Supported settings: {@link InlineDisplaySettings#SEPARATOR}.
+     */
+    public static final DisplayHandler<Collection<String>> INLINE_LIST = new InlineListDisplayHandler();
+
+    /**
+     * Display key value pair inline.
+     *
+     * Supported settings: {@link InlineDisplaySettings#SEPARATOR}, {@link MapDisplaySettings#OPERATOR}.
+     */
+    public static final DisplayHandler<Map<String, Object>> INLINE_MAP = new InlineMapDisplayHandler();
+}

src/main/java/com/onarandombox/MultiverseCore/display/handlers/InlineListDisplayHandler.java

@@ -0,0 +1,36 @@
+package com.onarandombox.MultiverseCore.display.handlers;
+
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.DisplayFormatException;
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
+import com.onarandombox.MultiverseCore.display.settings.InlineDisplaySettings;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+
+public class InlineListDisplayHandler implements DisplayHandler<Collection<String>> {
+
+    @Override
+    public Collection<String> format(@NotNull CommandSender sender, @NotNull ContentDisplay<Collection<String>> display)
+            throws DisplayFormatException {
+        StringBuilder builder = new StringBuilder();
+        String separator = display.getSetting(InlineDisplaySettings.SEPARATOR);
+
+        for (Iterator<String> iterator = display.getContents().iterator(); iterator.hasNext(); ) {
+            String content = iterator.next();
+            if (!display.getFilter().checkMatch(content)) {
+                continue;
+            }
+            builder.append(display.getColorTool().get()).append(content);
+            if (iterator.hasNext()) {
+                builder.append(separator);
+            }
+        }
+        return (builder.length() == 0)
+                ? Collections.singletonList(display.getEmptyMessage())
+                : Collections.singleton(builder.toString());
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/display/handlers/InlineMapDisplayHandler.java

@@ -0,0 +1,44 @@
+package com.onarandombox.MultiverseCore.display.handlers;
+
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.DisplayFormatException;
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
+import com.onarandombox.MultiverseCore.display.settings.InlineDisplaySettings;
+import com.onarandombox.MultiverseCore.display.settings.MapDisplaySettings;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.Map;
+
+public class InlineMapDisplayHandler implements DisplayHandler<Map<String, Object>> {
+
+    @Override
+    public Collection<String> format(@NotNull CommandSender sender,
+                                     @NotNull ContentDisplay<Map<String, Object>> display)
+            throws DisplayFormatException {
+        StringBuilder builder = new StringBuilder();
+        String separator = display.getSetting(InlineDisplaySettings.SEPARATOR);
+        String operator = display.getSetting(MapDisplaySettings.OPERATOR);
+
+        for (Iterator<Map.Entry<String, Object>> iterator = display.getContents().entrySet().iterator(); iterator.hasNext(); ) {
+            Map.Entry<String, Object> entry = iterator.next();
+            if (!display.getFilter().checkMatch(entry.getKey()) && !display.getFilter().checkMatch(entry.getValue())) {
+                continue;
+            }
+            builder.append(display.getColorTool().get())
+                    .append(entry.getKey())
+                    .append(operator)
+                    .append(display.getColorTool().get())
+                    .append(entry.getValue());
+            if (iterator.hasNext()) {
+                builder.append(separator);
+            }
+        }
+        return (builder.length() == 0)
+                ? Collections.singletonList(display.getEmptyMessage())
+                : Collections.singleton(builder.toString());
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/display/handlers/ListDisplayHandler.java

@@ -0,0 +1,22 @@
+package com.onarandombox.MultiverseCore.display.handlers;
+
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.DisplayFormatException;
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+public class ListDisplayHandler implements DisplayHandler<Collection<String>> {
+
+    @Override
+    public Collection<String> format(@NotNull CommandSender sender, @NotNull ContentDisplay<Collection<String>> display)
+            throws DisplayFormatException {
+        return display.getContents().stream()
+                .filter(display.getFilter()::checkMatch)
+                .map(s -> (ContentDisplay.LINE_BREAK.equals(s)) ? "" : display.getColorTool().get() + s)
+                .collect(Collectors.toList());
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/display/handlers/PagedListDisplayHandler.java

@@ -0,0 +1,105 @@
+package com.onarandombox.MultiverseCore.display.handlers;
+
+import com.onarandombox.MultiverseCore.display.ContentDisplay;
+import com.onarandombox.MultiverseCore.display.DisplayFormatException;
+import com.onarandombox.MultiverseCore.display.settings.PagedDisplaySettings;
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.ConsoleCommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class PagedListDisplayHandler extends ListDisplayHandler {
+
+    @Override
+    public Collection<String> format(@NotNull CommandSender sender, @NotNull ContentDisplay<Collection<String>> display)
+            throws DisplayFormatException {
+        if (dontNeedPaging(sender, display)) {
+            return super.format(sender, display);
+        }
+
+        int pages = 1;
+        int currentLength = 0;
+        int targetPage = display.getSetting(PagedDisplaySettings.SHOW_PAGE);
+        int linesPerPage = display.getSetting(PagedDisplaySettings.LINES_PER_PAGE);
+        List<String> content = new ArrayList<>(linesPerPage);
+
+        // Calculate the paging.
+        for (String line : display.getContents()) {
+            if (!display.getFilter().checkMatch(line)) {
+                continue;
+            }
+            // When it's the next page.
+            boolean isLineBreak = ContentDisplay.LINE_BREAK.equals(line);
+            if (isLineBreak || ++currentLength > linesPerPage) {
+                pages++;
+                currentLength = 0;
+                if (isLineBreak) {
+                    continue;
+                }
+            }
+            if (pages == targetPage) {
+                // Let first line be the header when no header is defined.
+                if (display.getHeader() == null) {
+                    display.setHeader(line);
+                    currentLength--;
+                    continue;
+                }
+                content.add(display.getColorTool().get() + line);
+            }
+        }
+
+        // Page out of range.
+        if (targetPage < 1 || targetPage > pages) {
+            if (pages == 1) {
+                throw new DisplayFormatException("There is only 1 page!");
+            }
+            throw new DisplayFormatException("Please enter a page from 1 to " + pages + ".");
+        }
+
+        // No content
+        if (content.size() == 0) {
+            content.add(display.getEmptyMessage());
+        }
+
+        // Add empty lines to make output length consistent.
+        if (display.getSetting(PagedDisplaySettings.DO_END_PADDING)) {
+            IntStream.range(0, linesPerPage - content.size()).forEach(i -> content.add(""));
+        }
+        display.setSetting(PagedDisplaySettings.TOTAL_PAGE, pages);
+
+        return content;
+    }
+
+    @Override
+    public void sendSubHeader(@NotNull CommandSender sender, @NotNull ContentDisplay<Collection<String>> display) {
+        if (dontNeedPaging(sender, display)) {
+            super.sendSubHeader(sender, display);
+            return;
+        }
+
+        if (display.getFilter().hasFilter()) {
+            sender.sendMessage(String.format("%s[ Page %s of %s, %s ]",
+                    ChatColor.GRAY,
+                    display.getSetting(PagedDisplaySettings.SHOW_PAGE),
+                    display.getSetting(PagedDisplaySettings.TOTAL_PAGE),
+                    display.getFilter().getFormattedString())
+            );
+            return;
+        }
+        sender.sendMessage(String.format("%s[ Page %s of %s ]",
+                ChatColor.GRAY,
+                display.getSetting(PagedDisplaySettings.SHOW_PAGE),
+                display.getSetting(PagedDisplaySettings.TOTAL_PAGE))
+        );
+    }
+
+    private boolean dontNeedPaging(CommandSender sender, ContentDisplay<Collection<String>> display) {
+        return sender instanceof ConsoleCommandSender
+                && !display.getSetting(PagedDisplaySettings.PAGE_IN_CONSOLE);
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/display/settings/DisplaySetting.java

@@ -1,10 +1,13 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display.settings;
+
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
 
 /**
  * Represents a setting option that can be used by {@link DisplayHandler}.
  *
  * @param <T>
  */
+@FunctionalInterface
 public interface DisplaySetting<T> {
 
      /**

src/main/java/com/onarandombox/MultiverseCore/display/settings/InlineDisplaySettings.java

@@ -0,0 +1,15 @@
+package com.onarandombox.MultiverseCore.display.settings;
+
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
+import org.bukkit.ChatColor;
+
+/**
+ * Collection of {@link DisplaySetting} that are used by various {@link DisplayHandler}.
+ */
+public class InlineDisplaySettings {
+
+    /**
+     * Inline separator. E.g. '1, 2, 3'
+     */
+    public static final DisplaySetting<String> SEPARATOR = () -> ChatColor.WHITE + ", ";
+}

src/main/java/com/onarandombox/MultiverseCore/display/settings/MapDisplaySettings.java

@@ -0,0 +1,15 @@
+package com.onarandombox.MultiverseCore.display.settings;
+
+import com.onarandombox.MultiverseCore.display.DisplayHandler;
+import org.bukkit.ChatColor;
+
+/**
+ * Collection of {@link DisplaySetting} that are used by various {@link DisplayHandler}.
+ */
+public class MapDisplaySettings {
+
+    /**
+     * The thing between a key value pair. E.g. 'Me = Smart'
+     */
+    public static final DisplaySetting<String> OPERATOR = () -> ChatColor.WHITE + " = ";
+}

src/main/java/com/onarandombox/MultiverseCore/display/settings/PagedDisplaySettings.java

@@ -1,11 +1,6 @@
-package com.onarandombox.MultiverseCore.displaytools;
+package com.onarandombox.MultiverseCore.display.settings;
 
-import org.bukkit.ChatColor;
+public class PagedDisplaySettings {
-
-/**
- * Collection of {@link DisplaySetting} that are used by various {@link DisplayHandler}.
- */
-public class DisplaySettings {
 
     /**
      * Page to display.
@@ -32,13 +27,4 @@ public class DisplaySettings {
      */
     public static final DisplaySetting<Boolean> PAGE_IN_CONSOLE = () -> false;
 
-    /**
-     * Inline separator. E.g. '1, 2, 3'
-     */
-    public static final DisplaySetting<String> SEPARATOR = () -> ChatColor.WHITE + ", ";
-
-    /**
-     * The thing between a key value pair. E.g. 'Me = Smart'
-     */
-    public static final DisplaySetting<String> OPERATOR = () -> ChatColor.WHITE + " = ";
 }

src/main/java/com/onarandombox/MultiverseCore/displaytools/DisplayHandler.java

@@ -1,61 +0,0 @@
-package com.onarandombox.MultiverseCore.displaytools;
-
-import com.google.common.base.Strings;
-import org.bukkit.ChatColor;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.Collection;
-
-/**
- * Handles the formatting and sending of all content by the {@link ContentDisplay}.
- *
- * @param <T>   Type of content to display.
- */
-public interface DisplayHandler<T> {
-
-    /**
-     * Formats the raw content into a {@link Collection<String>} for displaying to sender.
-     *
-     * @param display   The responsible {@link ContentDisplay}.
-     * @return The formatted content.
-     * @throws DisplayFormatException Issue occurred while formatting content. E.g. invalid page.
-     */
-    Collection<String> format(@NotNull ContentDisplay<T> display) throws DisplayFormatException;
-
-    /**
-     * Sends the header.
-     *
-     * @param display   The responsible {@link ContentDisplay}.
-     */
-    default void sendHeader(@NotNull ContentDisplay<T> display) {
-        if (!Strings.isNullOrEmpty(display.getHeader())) {
-            display.getSender().sendMessage(display.getHeader());
-        }
-    }
-
-    /**
-     * Sends info such as filter and page.
-     *
-     * @param display   The responsible {@link ContentDisplay}.
-     */
-    default void sendSubHeader(@NotNull ContentDisplay<T> display) {
-        if (display.getFilter().hasFilter()) {
-            display.getSender().sendMessage(String.format("%s[ %s ]",
-                    ChatColor.GRAY, display.getFilter().getFormattedString()));
-        }
-    }
-
-    /**
-     * Sends the content.
-     *
-     * @param display           The responsible {@link ContentDisplay}.
-     * @param formattedContent  The content after being formatted by {@link #format(ContentDisplay)}
-     */
-    default void sendBody(@NotNull ContentDisplay<T> display, Collection<String> formattedContent) {
-        if (formattedContent == null || formattedContent.size() == 0) {
-            display.getSender().sendMessage(display.getEmptyMessage());
-            return;
-        }
-        display.getSender().sendMessage(formattedContent.toArray(new String[0]));
-    }
-}

src/main/java/com/onarandombox/MultiverseCore/displaytools/DisplayHandlers.java

@@ -1,179 +0,0 @@
-package com.onarandombox.MultiverseCore.displaytools;
-
-import org.bukkit.ChatColor;
-import org.bukkit.command.ConsoleCommandSender;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.stream.Collectors;
-import java.util.stream.IntStream;
-
-/**
- * Various implementations of {@link DisplayHandler}.
- */
-public class DisplayHandlers {
-
-    /**
-     * Standard list display.
-     *
-     * Supported settings: none.
-     */
-    public static final DisplayHandler<Collection<String>> LIST = display -> display.getContents().stream()
-            .filter(display.getFilter()::checkMatch)
-            .map(s -> (ContentDisplay.LINE_BREAK.equals(s)) ? "" : display.getColorTool().get() + s)
-            .collect(Collectors.toList());
-
-    /**
-     * List display with paging.
-     *
-     * Supported settings: {@link DisplaySettings#SHOW_PAGE}, {@link DisplaySettings#LINES_PER_PAGE},
-     * {@link DisplaySettings#PAGE_IN_CONSOLE}, {@link DisplaySettings#DO_END_PADDING}.
-     */
-    public static final DisplayHandler<Collection<String>> PAGE_LIST = new DisplayHandler<Collection<String>>() {
-        @Override
-        public Collection<String> format(@NotNull ContentDisplay<Collection<String>> display) throws DisplayFormatException {
-            if (dontNeedPaging(display)) {
-                return LIST.format(display);
-            }
-
-            int pages = 1;
-            int currentLength = 0;
-            int targetPage = display.getSetting(DisplaySettings.SHOW_PAGE);
-            int linesPerPage = display.getSetting(DisplaySettings.LINES_PER_PAGE);
-            List<String> content = new ArrayList<>(linesPerPage);
-
-            // Calculate the paging.
-            for (String line : display.getContents()) {
-                if (!display.getFilter().checkMatch(line)) {
-                    continue;
-                }
-                // When it's the next page.
-                boolean isLineBreak = ContentDisplay.LINE_BREAK.equals(line);
-                if (isLineBreak || ++currentLength > linesPerPage) {
-                    pages++;
-                    currentLength = 0;
-                    if (isLineBreak) {
-                        continue;
-                    }
-                }
-                if (pages == targetPage) {
-                    // Let first line be the header when no header is defined.
-                    if (display.getHeader() == null) {
-                        display.setHeader(line);
-                        currentLength--;
-                        continue;
-                    }
-                    content.add(display.getColorTool().get() + line);
-                }
-            }
-
-            // Page out of range.
-            if (targetPage < 1 || targetPage > pages) {
-                if (pages == 1) {
-                    throw new DisplayFormatException("There is only 1 page!");
-                }
-                throw new DisplayFormatException("Please enter a page from 1 to " + pages + ".");
-            }
-
-            // No content
-            if (content.size() == 0) {
-                content.add(display.getEmptyMessage());
-            }
-
-            // Add empty lines to make output length consistent.
-            if (display.getSetting(DisplaySettings.DO_END_PADDING)) {
-                IntStream.range(0, linesPerPage - content.size()).forEach(i -> content.add(""));
-            }
-            display.setSetting(DisplaySettings.TOTAL_PAGE, pages);
-
-            return content;
-        }
-
-        @Override
-        public void sendSubHeader(@NotNull ContentDisplay<Collection<String>> display) {
-            if (dontNeedPaging(display)) {
-                LIST.sendSubHeader(display);
-                return;
-            }
-
-            if (display.getFilter().hasFilter()) {
-                display.getSender().sendMessage(String.format("%s[ Page %s of %s, %s ]",
-                        ChatColor.GRAY,
-                        display.getSetting(DisplaySettings.SHOW_PAGE),
-                        display.getSetting(DisplaySettings.TOTAL_PAGE),
-                        display.getFilter().getFormattedString())
-                );
-                return;
-            }
-            display.getSender().sendMessage(String.format("%s[ Page %s of %s ]",
-                    ChatColor.GRAY,
-                    display.getSetting(DisplaySettings.SHOW_PAGE),
-                    display.getSetting(DisplaySettings.TOTAL_PAGE))
-            );
-        }
-
-        private boolean dontNeedPaging(ContentDisplay<Collection<String>> display) {
-            return display.getSender() instanceof ConsoleCommandSender
-                    && !display.getSetting(DisplaySettings.PAGE_IN_CONSOLE);
-        }
-    };
-
-    /**
-     * Display a list inline.
-     *
-     * Supported settings: {@link DisplaySettings#SEPARATOR}.
-     */
-    public static final DisplayHandler<Collection<String>> INLINE_LIST = display -> {
-        StringBuilder builder = new StringBuilder();
-        String separator = display.getSetting(DisplaySettings.SEPARATOR);
-
-        for (Iterator<String> iterator = display.getContents().iterator(); iterator.hasNext(); ) {
-            String content = iterator.next();
-            if (!display.getFilter().checkMatch(content)) {
-                continue;
-            }
-            builder.append(display.getColorTool().get()).append(content);
-            if (iterator.hasNext()) {
-                builder.append(separator);
-            }
-        }
-        return (builder.length() == 0)
-                ? Collections.singletonList(display.getEmptyMessage())
-                : Collections.singleton(builder.toString());
-    };
-
-    /**
-     * Display key value pair inline.
-     *
-     * Supported settings: {@link DisplaySettings#SEPARATOR}, {@link DisplaySettings#OPERATOR}.
-     */
-    public static final DisplayHandler<Map<String, Object>> INLINE_MAP = display -> {
-        StringBuilder builder = new StringBuilder();
-        String separator = display.getSetting(DisplaySettings.SEPARATOR);
-        String operator = display.getSetting(DisplaySettings.OPERATOR);
-
-        for (Iterator<Entry<String, Object>> iterator = display.getContents().entrySet().iterator(); iterator.hasNext(); ) {
-            Entry<String, Object> entry = iterator.next();
-            if (!display.getFilter().checkMatch(entry.getKey()) && !display.getFilter().checkMatch(entry.getValue())) {
-                continue;
-            }
-            builder.append(display.getColorTool().get())
-                    .append(entry.getKey())
-                    .append(operator)
-                    .append(display.getColorTool().get())
-                    .append(entry.getValue());
-            if (iterator.hasNext()) {
-                builder.append(separator);
-            }
-        }
-        return (builder.length() == 0)
-                ? Collections.singletonList(display.getEmptyMessage())
-                : Collections.singleton(builder.toString());
-    };
-}