Some fixes + changes.

I'm going to push this as version 4.2 but I am still working on the
@requires annotation (which will nicely fix the issues with statistics
placeholders in SpongeAPI 5.2 by not letting people use that
placeholder).

Author: Wundero

src/main/java/me/rojo8399/placeholderapi/PlaceholderService.java

@@ -55,8 +55,8 @@ public interface PlaceholderService {
 	 * 
 	 * @return the expansion builder.
 	 */
-	public <S, O, V> ExpansionBuilder<S, O, V, ?> builder(Class<? extends S> source, Class<? extends O> observer,
-			Class<? extends V> value);
+	public <S, O, V> ExpansionBuilder<S, O, V, ? extends ExpansionBuilder<S, O, V, ?>> builder(
+			Class<? extends S> source, Class<? extends O> observer, Class<? extends V> value);
 
 	/**
 	 * Fill a map with placeholders from a template.
@@ -110,7 +110,7 @@ public default Pattern getDefaultPattern() {
 	 * 
 	 * @return the expansion builder.
 	 */
-	public ExpansionBuilder<?, ?, ?, ?> load(Object handle, String id, Object plugin);
+	public ExpansionBuilder<?, ?, ?, ? extends ExpansionBuilder<?, ?, ?, ?>> load(Object handle, String id, Object plugin);
 
 	/**
 	 * Create new ExpansionBuilders for all methods annotated with '@Placeholder' in
@@ -136,7 +136,7 @@ public default Pattern getDefaultPattern() {
 	 *            The plugin which holds the placeholders.
 	 * @return The list of builders matching the methods.
 	 */
-	public List<? extends ExpansionBuilder<?, ?, ?, ?>> loadAll(Object handle, Object plugin);
+	public List<? extends ExpansionBuilder<?, ?, ?, ? extends ExpansionBuilder<?, ?, ?, ?>>> loadAll(Object handle, Object plugin);
 
 	/**
 	 * Parse a placeholder.

src/main/java/me/rojo8399/placeholderapi/Token.java

@@ -30,18 +30,20 @@ of this software and associated documentation files (the "Software"), to deal
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;
 
-@Documented
-@Retention(RUNTIME)
-@Target(PARAMETER)
 /**
  * This annotation denotes the token which will hold more intricate details
- * about the placeholders needed. Supported types: Optional<String>, String.
+ * about the placeholders needed. The plugin will <b>TRY</b> to parse it into
+ * the given type of the parameter, but there are no guarantees beyond the basic
+ * primitives (and their box class), String and Optional<\String>.
  */
+@Documented
+@Retention(RUNTIME)
+@Target(PARAMETER)
 public @interface Token {
 
 	/**
-	 * 'Fix' the input token to be more useful. This will call toLowerCase and trim
-	 * on the string value of the token. This does nothing if the token is optional.
+	 * 'Fix' the input token to be more useful. This will call toLowerCase on the
+	 * string value of the token. This does nothing if the token is optional.
 	 * 
 	 * @return whether or not to fix the token
 	 */

src/main/java/me/rojo8399/placeholderapi/impl/PlaceholderServiceImpl.java

@@ -76,7 +76,7 @@ private PlaceholderServiceImpl() {
 	 * @see me.rojo8399.placeholderapi.PlaceholderService#builder()
 	 */
 	@Override
-	public <S, O, V> ExpansionBuilder<S, O, V, ?> builder(Class<? extends S> s, Class<? extends O> o,
+	public <S, O, V> ExpansionBuilder<S, O, V, ? extends ExpansionBuilder<S, O, V, ?>> builder(Class<? extends S> s, Class<? extends O> o,
 			Class<? extends V> v) {
 		return ExpansionBuilderImpl.builder(s, o, v);
 	}

src/main/java/me/rojo8399/placeholderapi/impl/placeholder/Defaults.java

@@ -354,7 +354,7 @@ private void calculateBalTop(Currency cur) {
 		List<UniqueAccount> baltop = new ArrayList<>();
 		baltop = this.users.stream().map(u -> u.getUniqueId()).filter(service::hasAccount)
 				.map(service::getOrCreateAccount).filter(Optional::isPresent).map(Optional::get)
-				.sorted((a, b) -> a.getBalance(cur).compareTo(b.getBalance(cur))).collect(Collectors.toList());
+				.sorted((a, b) -> -a.getBalance(cur).compareTo(b.getBalance(cur))).collect(Collectors.toList());
 		balTop.put(cur, baltop);
 		lastUpdate.put(cur, System.currentTimeMillis());
 	}
@@ -422,76 +422,79 @@ public Object economy(@Token(fix = true) @Nullable String token, @Nullable @Sour
 			String c = a[a.length - 1];
 			if (currencies.containsKey(c)) {
 				toUse = currencies.get(c);
+			} else {
+				t += "_" + c;
 			}
 		}
 		final Currency toUseFinal = toUse;
-		if (player == null) {
-			// fix t for baltop
-			int baltop = 0;
-			if (t.startsWith("baltop")) {
-				if (t.contains("_")) {
-					String aft = t.substring(t.indexOf("_") + 1);
-					t = t.substring(0, t.indexOf("_"));
-					try {
-						baltop = Integer.parseInt(aft);
-					} catch (Exception e) {
-						baltop = 5;
+		// fix t for baltop
+		int baltop = 0;
+		if (t.startsWith("baltop")) {
+			if (t.contains("_")) {
+				String aft = t.substring(t.indexOf("_") + 1);
+				t = t.substring(0, t.indexOf("_"));
+				try {
+					baltop = Integer.parseInt(aft);
+				} catch (Exception e) {
+					if (aft.contains("_")) {
+						String cur = aft.split("_")[1];
+						throw new NoValueException("That is not a valid currency!", currencies.keySet().stream()
+								.filter(s -> TypeUtils.closeTo(cur, s)).collect(Collectors.toList()));
+					} else {
+						throw new NoValueException("That is not a valid currency!", currencies.keySet().stream()
+								.filter(s -> TypeUtils.closeTo(aft, s)).collect(Collectors.toList()));
 					}
-				} else {
-					baltop = 5;
-				}
-				if (baltop <= 0) {
-					baltop = 1;
-				}
-				calculateBalTop(toUse);
-				List<UniqueAccount> baltop2 = balTop.get(toUse).subList(0, baltop);
-				if (t.startsWith("baltopf")) {
-					return Text.joinWith(Text.of(", "), baltop2.stream()
-							.map(a -> Text.of(a.getDisplayName(), ": " + toUseFinal.format(a.getBalance(toUseFinal))))
-							.collect(Collectors.toList()));
 				}
+			} else {
+				baltop = 5;
+			}
+			if (baltop <= 0) {
+				baltop = 1;
+			}
+			calculateBalTop(toUse);
+			List<UniqueAccount> baltop2 = balTop.get(toUse).stream().limit(baltop).collect(Collectors.toList());
+			if (t.startsWith("baltopf")) {
 				return Text.joinWith(Text.of(", "),
-						baltop2.stream()
-								.map(a -> Text.of(a.getDisplayName(), ": " + a.getBalance(toUseFinal).toPlainString()))
+						baltop2.stream().map(
+								a -> Text.of(a.getDisplayName(), ": " + toUseFinal.format(a.getBalance(toUseFinal))))
 								.collect(Collectors.toList()));
 			}
-			switch (t) {
-			case "display":
-				return toUse.getDisplayName();
-			case "plural_display":
-				return toUse.getPluralDisplayName();
-			case "symbol":
-				return toUse.getSymbol();
-			}
-			if (currencies.containsKey(t)) {
-				toUse = currencies.get(t);
-				Text amt = toUse.format(BigDecimal.valueOf(1234.56));
-				Text v = Text.of(toUse.getName() + " (" + toUse.getId() + ") - ");
-				return v.concat(amt);
-			}
-			throw new NoValueException();
+			return Text.joinWith(Text.of(", "),
+					baltop2.stream()
+							.map(a -> Text.of(a.getDisplayName(), ": " + a.getBalance(toUseFinal).toPlainString()))
+							.collect(Collectors.toList()));
 		}
-		// Don't handle nonexistent accounts here, instead throw error
-		UniqueAccount acc = service.getOrCreateAccount(player.getUniqueId()).get();
 		switch (t) {
-		case "balance":
-			return acc.getBalance(toUse).toPlainString();
-		case "bal_format":
-			return toUse.format(acc.getBalance(toUse));
 		case "display":
 			return toUse.getDisplayName();
 		case "plural_display":
 			return toUse.getPluralDisplayName();
 		case "symbol":
 			return toUse.getSymbol();
 		}
+		if (player != null) {
+			// Don't handle nonexistent accounts here, instead throw error
+			UniqueAccount acc = service.getOrCreateAccount(player.getUniqueId()).get();
+			switch (t) {
+			case "balance":
+				return acc.getBalance(toUse).toPlainString();
+			case "bal_format":
+				return toUse.format(acc.getBalance(toUse));
+			}
+		}
 		if (currencies.containsKey(t)) {
 			toUse = currencies.get(t);
 			Text amt = toUse.format(BigDecimal.valueOf(1234.56));
 			Text v = Text.of(toUse.getName() + " (" + toUse.getId() + ") - ");
 			return v.concat(amt);
 		}
-		throw new NoValueException();
+		if (t.contains("_")) {
+			String[] arr = t.split("_");
+			t = arr[arr.length - 1];
+		}
+		final String ft = t;
+		throw new NoValueException("That is not a valid currency!",
+				currencies.keySet().stream().filter(s -> TypeUtils.closeTo(ft, s)).collect(Collectors.toList()));
 	}
 
 	private long getDowntimeMillis() {
@@ -931,6 +934,7 @@ public Text sound(@Nullable @Source Player p, @Token(fix = true) String identifi
 	}
 
 	@Placeholder(id = "statistic")
+	// @Requires(spongeVersion = "[6.0)")
 	public Long stat(@Source Player player, @Token(fix = true) String t) {
 		return player.getOrNull(Keys.STATISTICS).entrySet().stream().filter(e -> {
 			String s = e.getKey().getId().replace("._", ".").toLowerCase();

src/main/java/me/rojo8399/placeholderapi/impl/placeholder/Expansion.java

@@ -23,7 +23,6 @@ of this software and associated documentation files (the "Software"), to deal
  */
 package me.rojo8399.placeholderapi.impl.placeholder;
 
-import java.lang.reflect.Method;
 import java.lang.reflect.Type;
 import java.net.URL;
 import java.util.ArrayList;
@@ -68,15 +67,27 @@ private static final boolean verifySource(Class<?> param) {
 	private String desc;
 	private boolean enabled = true;
 	private String id;
-	private Class<? extends O> observerClass;
+	private final Class<? extends O> observerClass;
 	private Object plugin;
 	private boolean relational = false;
 	private Runnable reloadListeners;
-	private Class<? extends S> sourceClass;
+	private final Class<? extends S> sourceClass;
 	private List<String> tokens;
 	private URL url;
 
-	private Class<? extends V> valueClass;
+	private final Class<? extends V> valueClass;
+	
+	public Class<? extends V> getValueClass() {
+		return valueClass;
+	}
+	
+	public Class<? extends S> getSourceClass() {
+		return sourceClass;
+	}
+	
+	public Class<? extends O> getObserverClass() {
+		return observerClass;
+	}
 
 	private String ver;
 
@@ -209,7 +220,6 @@ public Expansion(String id, Object plugin, String author, String desc, String ve
 		this.valueClass = value;
 		this.observerClass = observer;
 		this.relational = relational;
-		this.checkClasses();
 	}
 
 	/**
@@ -244,21 +254,6 @@ public final String author() {
 		return author;
 	}
 
-	private final void checkClasses() {
-		Class<? extends V> v = getValueClass();
-		if (this.valueClass == null || !v.isAssignableFrom(this.valueClass)) {
-			this.valueClass = v;
-		}
-		Class<? extends S> s = getSourceClass();
-		if (this.sourceClass == null || !s.isAssignableFrom(this.sourceClass)) {
-			this.sourceClass = s;
-		}
-		Class<? extends O> o = getObserverClass();
-		if (this.observerClass == null || !o.isAssignableFrom(this.observerClass)) {
-			this.observerClass = o;
-		}
-	}
-
 	/**
 	 * Attempt to cast an object to the Observer type. Returns null if it fails.
 	 * 
@@ -331,39 +326,13 @@ public <T> T getConfiguration() {
 		}
 	}
 
-	/**
-	 * @return The class representing the observer type.
-	 */
-	@SuppressWarnings("unchecked")
-	public final Class<? extends O> getObserverClass() {
-		Method m = getParseMethod();
-		return (Class<? extends O>) m.getParameterTypes()[1];
-	}
-
-	private final Method getParseMethod() {
-		Class<?> clazz = this.getClass();
-		return Arrays.asList(clazz.getDeclaredMethods()).stream()
-				.filter(m -> m.getName().equalsIgnoreCase("parse") && Arrays.asList(m.getGenericParameterTypes())
-						.stream().map(Type::getTypeName).anyMatch(s -> s.contains("java.util.Optional")))
-				.findAny().get(); // we know it exists ;)
-	}
-
 	/**
 	 * @return The holding plugin.
 	 */
 	public Object getPlugin() {
 		return plugin;
 	}
 
-	/**
-	 * @return The class representing the source type.
-	 */
-	@SuppressWarnings("unchecked")
-	public final Class<? extends S> getSourceClass() {
-		Method m = getParseMethod();
-		return (Class<? extends S>) m.getParameterTypes()[0];
-	}
-
 	public List<String> getSuggestions(String token) {
 		if (this.tokens.isEmpty()) {
 			return new ArrayList<>();
@@ -374,15 +343,6 @@ public List<String> getSuggestions(String token) {
 		return tokens.stream().filter(s -> TypeUtils.closeTo(s, token)).collect(Collectors.toList());
 	}
 
-	/**
-	 * @return The class representing the return type.
-	 */
-	@SuppressWarnings("unchecked")
-	public final Class<? extends V> getValueClass() {
-		Method m = getParseMethod();
-		return (Class<? extends V>) m.getReturnType();
-	}
-
 	/**
 	 * @return The id of the expansion.
 	 */

src/main/java/me/rojo8399/placeholderapi/impl/placeholder/ExpansionBuilderImpl.java

@@ -79,7 +79,7 @@ private static <S, O, V> ExpansionBuilderImpl<S, O, V> from(ExpansionBuilderImpl
 			return (ExpansionBuilderImpl<S, O, V>) builder;
 		}
 		ExpansionBuilderImpl<?, ?, ?> b = builder;
-		ExpansionBuilderImpl<S, O, V> n = unverified(exp.getSourceClass(), exp.getObserverClass(), exp.getValueClass());
+		ExpansionBuilderImpl<S, O, V> n = unverified(src(exp, builder), obs(exp, builder), val(exp, builder));
 		n.relational(b.relational).id(b.id).author(b.auth).description(b.desc).config(b.config).tokens(b.tokens)
 				.version(b.ver);
 		try {
@@ -96,6 +96,30 @@ private static <S, O, V> ExpansionBuilderImpl<S, O, V> from(ExpansionBuilderImpl
 		return n;
 	}
 
+	@SuppressWarnings("unchecked")
+	private static <O> Class<? extends O> obs(Expansion<?, O, ?> e, ExpansionBuilderImpl<?, ?, ?> b) {
+		if (e.getObserverClass() == null) {
+			return (Class<? extends O>) b.getObserverClass();
+		}
+		return e.getObserverClass();
+	}
+
+	@SuppressWarnings("unchecked")
+	private static <V> Class<? extends V> val(Expansion<?, ?, V> e, ExpansionBuilderImpl<?, ?, ?> b) {
+		if (e.getValueClass() == null) {
+			return (Class<? extends V>) b.getValueClass();
+		}
+		return e.getValueClass();
+	}
+
+	@SuppressWarnings("unchecked")
+	private static <S> Class<? extends S> src(Expansion<S, ?, ?> e, ExpansionBuilderImpl<?, ?, ?> b) {
+		if (e.getSourceClass() == null) {
+			return (Class<? extends S>) b.getSourceClass();
+		}
+		return e.getSourceClass();
+	}
+
 	private static ExpansionBuilderImpl<?, ?, ?> lfm(Object o, Method m, Object p, boolean rel) {
 		Store s = Store.get();
 		return unverified(s.getSourceType(m).orElse(Locatable.class), s.getObserverType(m).orElse(Locatable.class),
@@ -221,7 +245,9 @@ public Expansion<S, O, V> build() throws Exception {
 		if (verify) {
 			Preconditions.checkArgument(verify());
 		}
-		Expansion<S, O, V> exp = new Expansion<S, O, V>(id, plugin, auth, desc, ver, url, relational, tokens) {
+		Expansion<S, O, V> exp = new Expansion<S, O, V>(id, plugin, auth, desc, ver,
+				(url == null || url.isEmpty()) ? null : new URL(url), relational, tokens, this.sourceClass,
+				this.observerClass, this.returnClass) {
 			@Override
 			public V parse(S source, O observer, Optional<String> token) throws Exception {
 				return func.parse(source, observer, token);
@@ -241,6 +267,7 @@ public boolean reload() {
 				PlaceholderAPIPlugin.getInstance().registerListeners(listeners, plugin);
 			});
 		}
+		id = null;
 		return exp;
 	}