Created the PaperInstaller.java

src/main/java/de/gnmyt/mcdash/api/installer/PaperInstaller.java

@@ -0,0 +1,57 @@
+package de.gnmyt.mcdash.api.installer;
+
+import com.google.gson.Gson;
+import de.gnmyt.mcdash.api.Logger;
+import de.gnmyt.mcdash.api.ServerVersionManager;
+import okhttp3.OkHttpClient;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class PaperInstaller implements VersionInstaller {
+
+    private static final String PAPER_URL = "https://papermc.io/api/v2/projects/paper/versions/%s/builds/%s/downloads/paper-%s-%s.jar";
+    private static final String PAPER_API = "https://papermc.io/api/v2/projects/paper/versions/%s";
+
+    private final OkHttpClient client = new OkHttpClient();
+    private final Logger LOG = new Logger(PaperInstaller.class);
+
+
+    public String getPaperVersion(String version) {
+        try {
+            okhttp3.Request request = new okhttp3.Request.Builder().url(String.format(PAPER_API, version)).build();
+            okhttp3.Response response = client.newCall(request).execute();
+
+            if (response.code() == 200) {
+                HashMap json = new Gson().fromJson(response.body().string(), HashMap.class);
+                ArrayList builds = (ArrayList) json.get("builds");
+
+                return builds.get(0).toString().split("\\.")[0];
+            }
+
+            response.close();
+        } catch (Exception e) {
+            LOG.error("An error occurred while getting the paper version", e);
+        }
+
+        return null;
+    }
+
+    @Override
+    public boolean installVersion(String software, String version) {
+        try {
+            String paperVersion = getPaperVersion(version);
+            if (paperVersion == null) {
+                LOG.error("An error occurred while getting the paper version");
+                return false;
+            }
+
+            String downloadUrl = String.format(PAPER_URL, version, paperVersion, version, paperVersion);
+            return downloadFile(downloadUrl, new File(ServerVersionManager.getVersionFolder(), software + "-" + version + ".jar"));
+        } catch (Exception e) {
+            LOG.error("An error occurred while installing the paper version", e);
+            return false;
+        }
+    }
+}