add base PlaceholderAPI integration

Author: iLynxcat

src/main/java/org/modernbeta/admintoolbox/AdminToolboxPlugin.java

@@ -12,6 +12,7 @@
 import org.modernbeta.admintoolbox.commands.*;
 import org.modernbeta.admintoolbox.integration.BlueMapIntegration;
 import org.modernbeta.admintoolbox.integration.luckperms.LuckPermsIntegration;
+import org.modernbeta.admintoolbox.integration.placeholderapi.PlaceholderAPIIntegration;
 import org.modernbeta.admintoolbox.managers.FreezeManager;
 import org.modernbeta.admintoolbox.managers.admin.AdminManager;
 
@@ -36,6 +37,7 @@ public class AdminToolboxPlugin extends JavaPlugin {
 
 	private @Nullable BlueMapIntegration blueMapIntegration = null;
 	private @Nullable LuckPermsIntegration luckPermsIntegration = null;
+	private @Nullable PlaceholderAPIIntegration placeholderAPIIntegration = null;
 
 	private static final String ADMIN_STATE_CONFIG_FILENAME = "admin-state.yml";
 
@@ -94,6 +96,13 @@ public void onEnable() {
 			getLogger().warning("BlueMap API not found! Some features will be unavailable.");
 		}
 
+		try {
+			this.placeholderAPIIntegration = new PlaceholderAPIIntegration(this);
+			this.placeholderAPIIntegration.registerPlaceholders();
+		} catch (NoClassDefFoundError e) {
+			getLogger().warning("PlaceholderAPI is not available! Some features will be unavailable.");
+		}
+
 		if (getConfig().getBoolean("enable-stats")) {
 			getLogger().info("Enabling bStats for plugin statistics.");
 			// bStats - plugin analytics

src/main/java/org/modernbeta/admintoolbox/integration/placeholderapi/PlaceholderAPIIntegration.java

@@ -1,4 +1,20 @@
 package org.modernbeta.admintoolbox.integration.placeholderapi;
 
+import me.clip.placeholderapi.PlaceholderAPI;
+import org.modernbeta.admintoolbox.AdminToolboxPlugin;
+import org.modernbeta.admintoolbox.integration.placeholderapi.expansion.StreamerModePlaceholder;
+
 public class PlaceholderAPIIntegration {
+	private final AdminToolboxPlugin plugin;
+
+	private final StreamerModePlaceholder streamerModePlaceholder;
+
+	public PlaceholderAPIIntegration(AdminToolboxPlugin plugin) {
+		this.plugin = plugin;
+		this.streamerModePlaceholder = new StreamerModePlaceholder(plugin);
+	}
+
+	public boolean registerPlaceholders() {
+		return this.streamerModePlaceholder.register();
+	}
 }

src/main/java/org/modernbeta/admintoolbox/integration/placeholderapi/expansion/StreamerModePlaceholder.java

@@ -0,0 +1,44 @@
+package org.modernbeta.admintoolbox.integration.placeholderapi.expansion;
+
+import me.clip.placeholderapi.expansion.PlaceholderExpansion;
+import me.clip.placeholderapi.expansion.Relational;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.modernbeta.admintoolbox.AdminToolboxPlugin;
+
+import javax.annotation.Nullable;
+
+public class StreamerModePlaceholder extends PlaceholderExpansion implements Relational {
+	private final AdminToolboxPlugin plugin;
+
+	public StreamerModePlaceholder(AdminToolboxPlugin plugin) {
+		this.plugin = plugin;
+	}
+
+	@Override
+	public @NotNull String getIdentifier() {
+		return "streamermode";
+	}
+
+	@SuppressWarnings("UnstableApiUsage")
+	@Override
+	public @NotNull String getAuthor() {
+		return String.join(", ", plugin.getPluginMeta().getAuthors());
+	}
+
+	@SuppressWarnings("UnstableApiUsage")
+	@Override
+	public @NotNull String getVersion() {
+		return plugin.getPluginMeta().getVersion();
+	}
+
+	@Override
+	public boolean persist() {
+		return true;
+	}
+
+	@Override
+	public @Nullable String onPlaceholderRequest(Player viewer, Player wearer, String identifier) {
+		return null;
+	}
+}