Disposition

Make sure that when you declare the list you instantiate it, i.e. public ArrayList<String> StackableLootList = new ArrayList<>();

Thanks for the feedback! I know the caching is pretty rudimentary, but as far as I know GE prices only update once a day so it's not really a significant problem. Hadn't thought of making the results mutable though, the only problem I can see with doing that is in situations when you want to store the result as it was when you looked it up (maybe to monitor price changes).

With this you can lookup: Price Icon (32x32 normal and 96x96 large) Description Name Others I've also included some caching to minimize API lookups but you can disable this if you want. Usage: Create a new instance of the API: GrandExchangeApi api = new GrandExchangeApi(); Look up an item: GELookupResult result = api.lookup(itemId); Get data about the item: int price = result.price; String iconUrl = result.smallIconUrl; String description = result.description; //etc Snippet: import java.io.IOException; import java.net.URL; import java.util.HashMap; import java.util.Map; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * Utility class for access to the Grand Exchange API. */ public class GrandExchangeApi { /** * The URL of the API endpoint. */ private static final String API_LOCATION = "http://services.runescape.com/m=itemdb_oldschool/api/catalogue/detail.json?item=%d"; /** * The cache in which items that have already been looked up are stored. */ private final Map<Integer, GELookupResult> cache; /** * Creates a new Grand Exchange API instance, with caching enabled. */ public GrandExchangeApi() { this(true); } /** * Creates a new Grand Exchange API instance. * @param cache Whether to enable caching of results. */ public GrandExchangeApi(boolean cache) { if(cache) { this.cache = new HashMap<>(); } else { this.cache = null; } } /** * If caching is enabled, clears the cache so that new results are fetched on lookup. */ public void flushCache() { if(cache != null) { cache.clear(); } } /** * Looks up an item using the Grand Exchange API. This method blocks while waiting for the API result. * @param itemId the id to look up. * @return the result returned by the api. May be null if an error has occurred. */ public GELookupResult lookup(int itemId) { if(cache != null) { GELookupResult result = cache.get(itemId); if(result != null) { return result; } } String json; try { URL url = new URL(String.format(API_LOCATION, itemId)); Scanner scan = new Scanner(url.openStream()).useDelimiter("\\A"); json = scan.next(); scan.close(); } catch(IOException e) { return null; } GELookupResult result = parse(itemId, json); if(cache != null) { cache.put(itemId, result); } return result; } /** * Parses a GELookupResult from the JSON returned by the API. * @param itemId The item ID. * @param json The JSON returned by the server. * @return The serialized result. */ private static GELookupResult parse(int itemId, String json) { Pattern pattern = Pattern.compile("\"(?<key>[^\"]+)\":\"(?<value>[^\"]+)\""); Matcher m = pattern.matcher(json); Map<String, String> results = new HashMap<>(); while(m.find()) { results.put(m.group("key"), m.group("value")); } int price = 0; Matcher priceMatcher = Pattern.compile("\"price\":(?<price>\\d+)").matcher(json); if (priceMatcher.find()) { price = Integer.parseInt(priceMatcher.group("price")); } return new GELookupResult( results.get("icon"), results.get("icon_large"), results.get("type"), results.get("typeIcon"), results.get("name"), itemId, price ); } /** * A class representing a result from an API lookup. */ public static final class GELookupResult { public final String smallIconUrl, largeIconUrl, type, typeIcon, name; public final int id, price; private GELookupResult(String smallIconUrl, String largeIconUrl, String type, String typeIcon, String name, int id, int price) { this.smallIconUrl = smallIconUrl; this.largeIconUrl = largeIconUrl; this.type = type; this.typeIcon = typeIcon; this.name = name; this.id = id; this.price = price; } } }