[fixes #825] Implement AssetHandler

core/src/net/sf/openrocket/communication/AssetHandler.java

@@ -0,0 +1,61 @@
+package net.sf.openrocket.communication;
+
+import net.sf.openrocket.arch.SystemInfo;
+import net.sf.openrocket.arch.SystemInfo.Platform;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * This class handles assets extracted from a GitHub release page.
+ *
+ * @author Sibo Van Gool <sibo.vangool@hotmail.com>
+ */
+public class AssetHandler {
+    private static final Map<String, Platform> mapExtensionToOS = new HashMap<>();  // Map file extensions to operating system
+    private static final Map<Platform, String> mapOSToName = new HashMap<>();       // Map operating system to a name
+    static {
+        mapExtensionToOS.put(".dmg", Platform.MAC_OS);
+        mapExtensionToOS.put(".exe", Platform.WINDOWS);
+        mapExtensionToOS.put(".AppImage", Platform.UNIX);
+        mapExtensionToOS.put(".jar", null);
+
+        mapOSToName.put(Platform.MAC_OS, "Mac OS");
+        mapOSToName.put(Platform.WINDOWS, "Windows");
+        mapOSToName.put(Platform.UNIX, "Linux");
+        mapOSToName.put(null, "JAR");
+    }
+
+    /**
+     * Maps a list of asset URLs to their respective operating system.
+     * E.g. "https://github.com/openrocket/openrocket/releases/download/release-15.03/OpenRocket-15.03.dmg" is mapped to
+     * "Mac OS".
+     * @param urls list of asset URLs
+     * @return map with as key the operating system and as value the corresponding asset URL
+     */
+    public static Map<String, String> mapURLToOSName(List<String> urls) {
+        Map<String, String> output = new TreeMap<>();
+        if (urls == null) return null;
+
+        for (String url : urls) {
+            for (String ext : mapExtensionToOS.keySet()) {
+                if (url.endsWith(ext)) {
+                    output.put(mapOSToName.get(mapExtensionToOS.get(ext)), url);
+                }
+            }
+        }
+        return output;
+    }
+
+    /**
+     * Returns the OS name based on the operating system that the user is running on, or the value stored in preferences.
+     * @return operating system name
+     */
+    public static String getOSName() {
+        Platform currentPlatform = SystemInfo.getPlatform();
+        // TODO: select right option based on preference
+        return mapOSToName.get(currentPlatform);
+    }
+}