Added generic mod checker

src/main/java/cr0s/warpdrive/conf/ModRequirementChecker.java

@@ -0,0 +1,31 @@
+package cr0s.warpdrive.conf;
+
+import org.w3c.dom.Element;
+import org.w3c.dom.NodeList;
+
+import cpw.mods.fml.common.Loader;
+
+public class ModRequirementChecker {
+
+	public static String getMissingMods(Element e) throws InvalidXmlException {
+
+		String missingMods = "";
+
+		NodeList mods = e.getElementsByTagName("mod");
+		for (int j = 0; j < mods.getLength(); j++) {
+			Element mod = (Element) mods.item(j);
+			if (!mod.hasAttribute("name")) {
+				throw new InvalidXmlException("A mod requirement is missing the name attribute!");
+			}
+
+			String name = mod.getAttribute("name");
+			if (!Loader.isModLoaded(name)) {
+				missingMods = missingMods + name + ", ";
+			}
+			
+		}
+		
+		return missingMods;
+	}
+
+}