nullcheck

src/org/polymart/mcplugin/Main.java

@@ -16,6 +16,7 @@
 import org.polymart.mcplugin.api.PolymartAccount;
 import org.polymart.mcplugin.commands.PolymartCommand;
 import org.polymart.mcplugin.commands.UpdateCommand;
+import org.polymart.mcplugin.hooks.PolymartExpansion;
 import org.polymart.mcplugin.server.UploadServerInfo;
 
 import java.util.*;
@@ -39,6 +40,10 @@ public void onEnable(){
         UpdateCheck.setup();
         UploadServerInfo.setup();
 
+        if (getServer().getPluginManager().getPlugin("PlaceholderAPI") != null){
+            new PolymartExpansion(this).register();
+        }
+
         this.getCommand("polymart").setExecutor(new PolymartCommand());
         this.getCommand("update").setExecutor(new UpdateCommand());
 

src/org/polymart/mcplugin/actions/UpdateCheck.java

@@ -30,6 +30,7 @@
 import java.text.SimpleDateFormat;
 import java.util.*;
 import java.util.jar.JarFile;
+import java.util.stream.Collectors;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 import java.util.zip.ZipOutputStream;
@@ -373,6 +374,7 @@ public static void checkForUpdatesResponse(JSONWrapper wrapper, Map<String, Stri
         }
 
         upToDate.sort(Comparator.comparing((UpdateInfo a) -> a.name));
+        canDownloadFromPolymart = canDownloadFromPolymart.stream().filter(Objects::nonNull).collect(Collectors.toList());
         canDownloadFromPolymart.sort(Comparator.comparing((UpdateInfo a) -> a.name));
         untracked.sort(Comparator.comparing((UpdateInfo a) -> a.name));
         updateAvailable.sort(Comparator.comparing((UpdateInfo a) -> a.name));

src/org/polymart/mcplugin/hooks/PolymartExpansion.java

@@ -0,0 +1,78 @@
+package org.polymart.mcplugin.hooks;
+
+import me.clip.placeholderapi.expansion.PlaceholderExpansion;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.polymart.mcplugin.Main;
+
+public class PolymartExpansion extends PlaceholderExpansion {
+
+    private final Main plugin;
+
+    public PolymartExpansion(Main plugin) {
+        this.plugin = plugin;
+    }
+
+    @Override
+    public boolean persist() {
+        return true;
+    }
+
+    @Override
+    public @NotNull String getIdentifier() {
+        return "polymart";
+    }
+
+    @Override
+    public @NotNull String getAuthor() {
+        return "Polymart";
+    }
+
+    @Override
+    public @NotNull String getVersion() {
+        return plugin.getServer().getVersion();
+    }
+
+    @Override
+    public @Nullable String onPlaceholderRequest(Player player, @NotNull String params) {
+        String[] args = params.split("_");
+
+        if (args.length == 0) {
+            return null;
+        }
+
+        switch (args[0].toLowerCase()) {
+            case "version":
+                if (args.length != 2) {
+                    return null;
+                }
+                Plugin otherPlugin = plugin.getServer().getPluginManager().getPlugin(args[1]);
+                if (otherPlugin == null) {
+                    return null;
+                }
+                return otherPlugin.getDescription().getVersion();
+            case "description":
+                if (args.length != 2) {
+                    return null;
+                }
+                Plugin otherPlugin1 = plugin.getServer().getPluginManager().getPlugin(args[1]);
+                if (otherPlugin1 == null) {
+                    return null;
+                }
+                return otherPlugin1.getDescription().getDescription();
+            case "author":
+                if (args.length != 2) {
+                    return null;
+                }
+                Plugin otherPlugin2 = plugin.getServer().getPluginManager().getPlugin(args[1]);
+                if (otherPlugin2 == null) {
+                    return null;
+                }
+                return String.join(", ", otherPlugin2.getDescription().getAuthors());
+        }
+
+        return null;
+    }
+}

src/plugin.yml

@@ -5,6 +5,8 @@ api-version: "1.13"
 author: Polymart
 website: https://polymart.org
 load: STARTUP
+softdepend:
+  - PlaceholderAPI
 commands:
   polymart:
     description: Polymart commands