2 files changed, 187 insertions, 0 deletions
diff --git a/src/eu/equalparts/cardbase/utils/IO.java b/src/eu/equalparts/cardbase/utils/IO.java
new file mode 100644
index 0000000..5d4bef5
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+++ b/src/eu/equalparts/cardbase/utils/IO.java
@@ -0,0 +1,35 @@
+package eu.equalparts.cardbase.utils;
+
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * This class simply holds an {@code ObjectMapper} to be used whenever JSON must be parsed.
+ * In the future it may be removed in favour of individual mappers for each function.
+ * 
+ * @author Eduardo Pedroni
+ */
+public final class IO {
+	
+	/**
+	 * The Jackson {@code ObjectMapper} which parses fetched JSON files.
+	 */
+	public static final ObjectMapper jsonMapper = createMapper();
+
+	/**
+	 * Private constructor, this class is not to be instantiated.
+	 */
+	private IO() {}
+	
+	/**
+	 * Instantiate and configure Jackson mapper statically. 
+	 * 
+	 * @return the {@code ObjectMapper}, ready to use.
+	 */
+	private static ObjectMapper createMapper() {
+		ObjectMapper objectMapper = new ObjectMapper();
+		// TODO decide what to do about this
+		objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+		return objectMapper;
+	}
+}
diff --git a/src/eu/equalparts/cardbase/utils/MTGUniverse.java b/src/eu/equalparts/cardbase/utils/MTGUniverse.java
new file mode 100644
index 0000000..7211f47
--- /dev/null
+++ b/src/eu/equalparts/cardbase/utils/MTGUniverse.java
@@ -0,0 +1,152 @@
+package eu.equalparts.cardbase.utils;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.HashMap;
+
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.JsonMappingException;
+
+import eu.equalparts.cardbase.data.Card;
+import eu.equalparts.cardbase.data.CardSet;
+import eu.equalparts.cardbase.data.FullCardSet;
+
+/**
+ * Access point to the complete set of cards that exist in the
+ * MTG universe. This class has a series of utility functions that
+ * query remote databases to acquire card information.
+ * <br>
+ * Conversely, {@code CardbaseManager}'s methods are used solely to
+ * acquire information regarding the loaded cardbase, which will
+ * most likely contain only a subset of the MTG universe.
+ * 
+ * @author Eduardo Pedroni
+ */
+public final class MTGUniverse {
+
+	/**
+	 * The base URL from where the information is fetched.
+	 */
+	private static final String BASE_URL = "http://mtgjson.com/json/";
+	/**
+	 * If the upstream set code list can't be loaded, this is loaded instead.
+	 */
+	private static final String FALLBACK_LIST_PATH = "/setlist.json";
+	/**
+	 * A cache of CardSets to avoid querying the server many times for the same information.
+	 */
+	private static ArrayList<CardSet> cardSets;
+
+	/**
+	 * A cache of {@code FullCardSets} to avoid querying the server many times for the same information.
+	 */
+	private static HashMap<String, FullCardSet> cardSetCache = new HashMap<String, FullCardSet>();
+
+	/**
+	 * Private constructor, this class is not to be instantiated.
+	 */
+	private MTGUniverse() {}
+	
+	/**
+	 * Returns the specified card in the form of a {@code Card} object. If the specified number does
+	 * not correspond to a card in the set or the specified set code does not correspond to a set,
+	 * this returns null.
+	 * 
+	 * @param setCode the set to which the requested card belongs.
+	 * @param number the requested card's set number.
+	 * @return the requested {@code Card} or null if no card is found.
+	 * 
+	 * @throws JsonParseException if the upstream JSON is not formatted correctly.
+	 * @throws JsonMappingException if the upstream JSON does not map to a local class.
+	 * @throws IOException if a low-level I/O problem (unexpected end-of-input, network error) occurs.
+	 */
+	public static Card getCard(String setCode, String number) throws JsonParseException, JsonMappingException, IOException {
+		Card card = null;
+		FullCardSet fullCardSet = getFullCardSet(setCode);
+		
+		if (fullCardSet != null) {
+			card = fullCardSet.getCardByNumber(number);
+		}
+		
+		return card;
+	}
+	
+	/**
+	 * Returns the specified set in the form of a {@code FullCardSet} object. If the specified
+	 * set code does not correspond to a set, this returns null.
+	 * 
+	 * @param setCode the code of the set to be returned.
+	 * @return the requested {@code FullCardSet} or null if no set matches the given code.
+	 * 
+	 * @throws JsonParseException if the upstream JSON is not formatted correctly.
+	 * @throws JsonMappingException if the upstream JSON does not map to {@code FullCardSet}.
+	 * @throws IOException if a low-level I/O problem (unexpected end-of-input, network error) occurs.
+	 */
+	public static FullCardSet getFullCardSet(String setCode) throws JsonParseException, JsonMappingException, IOException {
+		FullCardSet requestedSet = null;
+		String validCode = validateSetCode(setCode);
+		if (validCode != null) {
+			// if the set is cached, no need to fetch
+			if (cardSetCache.containsKey(validCode)) {
+				requestedSet = cardSetCache.get(validCode);
+			} 
+			// not cached; fetch, cache and return it
+			else {
+				requestedSet = IO.jsonMapper.readValue(new URL(BASE_URL + validCode + ".json"), FullCardSet.class);
+				// MTG JSON does not include set code in the card information, but it is useful for sorting
+				for (Card card : requestedSet.getCards()) {
+					card.setCode = validCode;
+				}
+				cardSetCache.put(validCode, requestedSet);
+			}
+		}
+		return requestedSet;
+	}
+	
+	/**
+	 * @return a list of all card sets in the form of {@code CardSet} objects.
+	 */
+	public static ArrayList<CardSet> getCardSetList() {
+		// if the list isn't cached, fetch and cache it
+		if (cardSets == null) {
+			try {
+				cardSets = IO.jsonMapper.readValue(new URL(BASE_URL + "SetList.json"), new TypeReference<ArrayList<CardSet>>() {});
+			} catch (Exception e) {
+				System.out.println("Error: could not fetch/parse set code list from upstream, loading fallback json...");
+				e.printStackTrace();
+				
+				try {
+					cardSets = IO.jsonMapper.readValue(MTGUniverse.class.getResourceAsStream(FALLBACK_LIST_PATH), new TypeReference<ArrayList<CardSet>>() {});
+				} catch (Exception f) {
+					System.out.println("Error: could not parse fallback set code list, aborting...");
+					f.printStackTrace();
+					System.exit(1);
+				}
+			}
+		}
+		return cardSets;
+	}
+	
+	/**
+	 * This method effectively converts different set code spellings
+	 * into the format parsed from the set code list.
+	 * <br>
+	 * For instance, if "m15" is passed as the argument, this returns
+	 * "M15", which is the set code as it is stated in the formal list.
+	 * If the specified set code does not approximate any entry from
+	 * the list, this returns null.
+	 * 
+	 * @param setCode the set code to be validated.
+	 * @return the valid form of the set code if any, null otherwise.
+	 */
+	public static String validateSetCode(String setCode) {
+		for (CardSet cardSet : getCardSetList()) {
+			if (cardSet.getCode().equalsIgnoreCase(setCode)) {
+				return cardSet.getCode();
+			}
+		}
+		return null;
+	}
+}