Merge branch 'master' into gradle

# Conflicts:
#	pom.xml

src/main/java/me/clip/placeholderapi/PlaceholderAPI.java

@@ -27,40 +27,118 @@ import me.clip.placeholderapi.events.ExpansionUnregisterEvent;
 import me.clip.placeholderapi.expansion.Cacheable;
 import me.clip.placeholderapi.expansion.PlaceholderExpansion;
 import me.clip.placeholderapi.expansion.Relational;
+import me.clip.placeholderapi.replacer.CharsReplacer;
+import me.clip.placeholderapi.replacer.Replacer;
+import me.clip.placeholderapi.replacer.Replacer.Closure;
 import me.clip.placeholderapi.util.Msg;
-import org.apache.commons.lang.Validate;
 import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
-import java.util.*;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
-import static me.clip.placeholderapi.util.Msg.color;
+public final class PlaceholderAPI
+{
 
-public class PlaceholderAPI {
+	private static final Replacer REPLACER_PERCENT = new CharsReplacer(Closure.PERCENT);
+	private static final Replacer REPLACER_BRACKET = new CharsReplacer(Closure.BRACKET);
 
+	private static final Map<String, PlaceholderHook> PLACEHOLDERS = new HashMap<>();
+
+
+	@Deprecated
 	private static final Pattern PLACEHOLDER_PATTERN            = Pattern.compile("[%]([^%]+)[%]");
+	@Deprecated
 	private static final Pattern BRACKET_PLACEHOLDER_PATTERN    = Pattern.compile("[{]([^{}]+)[}]");
+	@Deprecated
 	private static final Pattern RELATIONAL_PLACEHOLDER_PATTERN = Pattern.compile("[%](rel_)([^%]+)[%]");
-    private static final Map<String, PlaceholderHook> placeholders = new HashMap<>();
 
-    private PlaceholderAPI() {
+
+	private PlaceholderAPI()
+	{
 	}
 
+
+	// === Current API ===
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
+	 *
+	 * @param player Player to parse the placeholders against
+	 * @param text   Text to set the placeholder values in
+	 * @return String containing all translated placeholders
+	 */
+	@NotNull
+	public static String setPlaceholders(@Nullable final OfflinePlayer player, @NotNull final String text)
+	{
+		return REPLACER_PERCENT.apply(text, player, PLACEHOLDERS::get);
+	}
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
+	 *
+	 * @param player Player to parse the placeholders against
+	 * @param text   List of Strings to set the placeholder values in
+	 * @return String containing all translated placeholders
+	 */
+	@NotNull
+	public static List<String> setPlaceholders(@Nullable final OfflinePlayer player, @NotNull final List<@NotNull String> text)
+	{
+		return text.stream().map(line -> setPlaceholders(player, line)).collect(Collectors.toList());
+	}
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>The pattern of a valid placeholder is {@literal {<identifier>_<params>}}.
+	 *
+	 * @param player Player to parse the placeholders against
+	 * @param text   Text to set the placeholder values in
+	 *
+	 * @return String containing all translated placeholders
+	 */
+	@NotNull
+	public static String setBracketPlaceholders(@Nullable final OfflinePlayer player, @NotNull final String text)
+	{
+		return REPLACER_BRACKET.apply(text, player, PLACEHOLDERS::get);
+	}
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>The pattern of a valid placeholder is {@literal {<identifier>_<params>}}.
+	 *
+	 * @param player Player to parse the placeholders against
+	 * @param text   List of Strings to set the placeholder values in
+	 *
+	 * @return String containing all translated placeholders
+	 */
+	@NotNull
+	public static List<String> setBracketPlaceholders(@Nullable final OfflinePlayer player, @NotNull final List<@NotNull String> text)
+	{
+		return text.stream().map(line -> setBracketPlaceholders(player, line)).collect(Collectors.toList());
+	}
+
+
 	/**
 	 * Check if a specific placeholder identifier is currently registered
 	 *
 	 * @param identifier The identifier to check
 	 * @return true if identifier is already registered
 	 */
-    public static boolean isRegistered(String identifier) {
+	public static boolean isRegistered(@NotNull final String identifier)
-        return getRegisteredIdentifiers().stream()
+	{
-                .filter(id -> id.equalsIgnoreCase(identifier))
+		return PLACEHOLDERS.containsKey(identifier.toLowerCase());
-                .findFirst().orElse(null) != null;
 	}
 
 	/**
@@ -72,17 +150,14 @@ public class PlaceholderAPI {
 	 * @return true if the hook was successfully registered, false if there is already a hook
 	 * registered for the specified identifier
 	 */
-    public static boolean registerPlaceholderHook(String identifier, PlaceholderHook placeholderHook) {
+	public static boolean registerPlaceholderHook(@NotNull final String identifier, @NotNull final PlaceholderHook placeholderHook)
-        Validate.notNull(identifier, "Identifier can not be null");
+	{
-        Validate.notNull(placeholderHook, "Placeholderhook can not be null");
+		return PLACEHOLDERS.putIfAbsent(identifier.toLowerCase(), placeholderHook) == null;
-
-        if (isRegistered(identifier)) {
-            return false;
 	}
 
-        placeholders.put(identifier.toLowerCase(), placeholderHook);
+	public static boolean registerPlaceholderHook(@NotNull final Plugin plugin, @NotNull final PlaceholderHook placeholderHook)
-
+	{
-        return true;
+		return registerPlaceholderHook(plugin.getName(), placeholderHook);
 	}
 
 	/**
@@ -92,18 +167,26 @@ public class PlaceholderAPI {
 	 * @return true if the placeholder hook was successfully unregistered, false if there was no
 	 * placeholder hook registered for the identifier specified
 	 */
-    public static boolean unregisterPlaceholderHook(String identifier) {
+	public static boolean unregisterPlaceholderHook(@NotNull final String identifier)
-        Validate.notNull(identifier, "Identifier can not be null");
+	{
-        return placeholders.remove(identifier.toLowerCase()) != null;
+		return PLACEHOLDERS.remove(identifier.toLowerCase()) != null;
 	}
 
+	public static boolean unregisterPlaceholderHook(@NotNull final Plugin plugin)
+	{
+		return unregisterPlaceholderHook(plugin.getName());
+	}
+
+
 	/**
 	 * Get all registered placeholder identifiers
 	 *
 	 * @return All registered placeholder identifiers
 	 */
-    public static Set<String> getRegisteredIdentifiers() {
+	@NotNull
-        return ImmutableSet.copyOf(placeholders.keySet());
+	public static Set<String> getRegisteredIdentifiers()
+	{
+		return ImmutableSet.copyOf(PLACEHOLDERS.keySet());
 	}
 
 	/**
@@ -111,11 +194,116 @@ public class PlaceholderAPI {
 	 *
 	 * @return Copy of the internal placeholder map
 	 */
-    public static Map<String, PlaceholderHook> getPlaceholders() {
+	@NotNull
-        return ImmutableMap.copyOf(placeholders);
+	public static Map<String, PlaceholderHook> getPlaceholders()
+	{
+		return ImmutableMap.copyOf(PLACEHOLDERS);
 	}
 
-    public static Set<PlaceholderExpansion> getExpansions() {
+
+	/**
+	 * Unregister ALL placeholder hooks that are currently registered
+	 */
+	protected static void unregisterAll()
+	{
+		unregisterAllProvidedExpansions();
+		PLACEHOLDERS.clear();
+	}
+
+	/**
+	 * Unregister all expansions provided by PlaceholderAPI
+	 */
+	public static void unregisterAllProvidedExpansions()
+	{
+		final Set<PlaceholderHook> set = new HashSet<>(PLACEHOLDERS.values());
+
+		for (PlaceholderHook hook : set)
+		{
+			if (hook instanceof PlaceholderExpansion)
+			{
+				final PlaceholderExpansion expansion = (PlaceholderExpansion) hook;
+
+				if (!expansion.persist())
+				{
+					unregisterExpansion(expansion);
+				}
+			}
+
+			if (hook instanceof Cacheable)
+			{
+				((Cacheable) hook).clear();
+			}
+		}
+	}
+
+	public static boolean registerExpansion(@NotNull final PlaceholderExpansion expansion)
+	{
+		final ExpansionRegisterEvent event = new ExpansionRegisterEvent(expansion);
+		Bukkit.getPluginManager().callEvent(event);
+
+		if (event.isCancelled())
+		{
+			return false;
+		}
+
+		return registerPlaceholderHook(expansion.getIdentifier(), expansion);
+	}
+
+	public static boolean unregisterExpansion(@NotNull final PlaceholderExpansion expansion)
+	{
+		if (unregisterPlaceholderHook(expansion.getIdentifier()))
+		{
+			Bukkit.getPluginManager().callEvent(new ExpansionUnregisterEvent(expansion));
+			return true;
+		}
+
+		return false;
+	}
+
+
+	// === Deprecated API ===
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>You set the pattern yourself through this method.
+	 *
+	 * @param player   Player to parse the placeholders against
+	 * @param text     Text to set the placeholder values in
+	 * @param pattern  The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
+	 *                 identifier from the params
+	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
+	 * @return The text containing the parsed placeholders
+	 * @deprecated Please use {@link #setPlaceholders(OfflinePlayer, String)} instead
+	 */
+	@NotNull
+	@Deprecated
+	public static String setPlaceholders(@Nullable final OfflinePlayer player, @NotNull final String text, @NotNull final Pattern pattern, final boolean colorize)
+	{
+		return setPlaceholders(player, text);
+	}
+
+	/**
+	 * Translates all placeholders into their corresponding values.
+	 * <br>You set the pattern yourself through this method.
+	 *
+	 * @param player   Player to parse the placeholders against
+	 * @param text     List of Strings to set the placeholder values in
+	 * @param pattern  The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
+	 *                 identifier from the params
+	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
+	 * @return String containing all translated placeholders
+	 * @deprecated Please use {@link #setPlaceholders(OfflinePlayer, List)} instead
+	 */
+	@NotNull
+	@Deprecated
+	public static List<String> setPlaceholders(@Nullable final OfflinePlayer player, @NotNull final List<String> text, @NotNull final Pattern pattern, final boolean colorize)
+	{
+		return setPlaceholders(player, text);
+	}
+
+	@Deprecated
+	public static Set<PlaceholderExpansion> getExpansions()
+	{
 		Set<PlaceholderExpansion> set = getPlaceholders().values().stream()
 														 .filter(PlaceholderExpansion.class::isInstance).map(PlaceholderExpansion.class::cast)
 														 .collect(Collectors.toCollection(HashSet::new));
@@ -128,8 +316,11 @@ public class PlaceholderAPI {
 	 *
 	 * @param text String to check
 	 * @return true if String contains any registered placeholder identifiers, false otherwise
+	 * @deprecated Will be removed in a future release.
 	 */
-    public static boolean containsPlaceholders(String text) {
+	@Deprecated
+	public static boolean containsPlaceholders(String text)
+	{
 		return text != null && PLACEHOLDER_PATTERN.matcher(text).find();
 	}
 
@@ -138,23 +329,14 @@ public class PlaceholderAPI {
 	 *
 	 * @param text String to check
 	 * @return true if String contains any registered placeholder identifiers, false otherwise
+	 * @deprecated Will be removed in a future release.
 	 */
-    public static boolean containsBracketPlaceholders(String text) {
+	@Deprecated
+	public static boolean containsBracketPlaceholders(String text)
+	{
 		return text != null && BRACKET_PLACEHOLDER_PATTERN.matcher(text).find();
 	}
 
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>The pattern of a valid placeholder is {@literal {<identifier>_<params>}}.
-     *
-     * @param player Player to parse the placeholders against
-     * @param text   List of Strings to set the placeholder values in
-     * @return String containing all translated placeholders
-     */
-    public static List<String> setBracketPlaceholders(OfflinePlayer player, List<String> text) {
-        return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, true);
-    }
-
 	/**
 	 * Translates all placeholders into their corresponding values.
 	 * <br>The pattern of a valid placeholder is {@literal {<identifier>_<params>}}.
@@ -163,23 +345,14 @@ public class PlaceholderAPI {
 	 * @param text     List of Strings to set the placeholder values in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return String containing all translated placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, List)} instead.
 	 */
-    public static List<String> setBracketPlaceholders(OfflinePlayer player, List<String> text, boolean colorize) {
+	@Deprecated
+	public static List<String> setBracketPlaceholders(OfflinePlayer player, List<String> text, boolean colorize)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, colorize);
 	}
 
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
-     *
-     * @param player Player to parse the placeholders against
-     * @param text   List of Strings to set the placeholder values in
-     * @return String containing all translated placeholders
-     */
-    public static List<String> setPlaceholders(OfflinePlayer player, List<String> text) {
-        return setPlaceholders(player, text, PLACEHOLDER_PATTERN, true);
-    }
-
 	/**
 	 * Translates all placeholders into their corresponding values.
 	 * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
@@ -188,8 +361,11 @@ public class PlaceholderAPI {
 	 * @param text     List of Strings to set the placeholder values in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return String containing all translated placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, List)} instead.
 	 */
-    public static List<String> setPlaceholders(OfflinePlayer player, List<String> text, boolean colorize) {
+	@Deprecated
+	public static List<String> setPlaceholders(OfflinePlayer player, List<String> text, boolean colorize)
+	{
 		return setPlaceholders(player, text, PLACEHOLDER_PATTERN, colorize);
 	}
 
@@ -202,43 +378,14 @@ public class PlaceholderAPI {
 	 * @param pattern The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
 	 *                identifier from the params
 	 * @return String containing all translated placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, List)} instead.
 	 */
-    public static List<String> setPlaceholders(OfflinePlayer player, List<String> text, Pattern pattern) {
+	@Deprecated
+	public static List<String> setPlaceholders(OfflinePlayer player, List<String> text, Pattern pattern)
+	{
 		return setPlaceholders(player, text, pattern, true);
 	}
 
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>You set the pattern yourself through this method.
-     *
-     * @param player   Player to parse the placeholders against
-     * @param text     List of Strings to set the placeholder values in
-     * @param pattern  The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
-     *                 identifier from the params
-     * @param colorize If color codes (&[0-1a-fk-o]) should be translated
-     * @return String containing all translated placeholders
-     */
-    public static List<String> setPlaceholders(OfflinePlayer player, List<String> text, Pattern pattern, boolean colorize) {
-        if (text == null) {
-            return null;
-        }
-
-        return text.stream()
-                .map(line -> setPlaceholders(player, line, pattern, colorize))
-                .collect(Collectors.toList());
-    }
-
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>The pattern of a valid placeholder is {@literal {<identifier>_<params>}}.
-     *
-     * @param player Player to parse the placeholders against
-     * @param text   Text to set the placeholder values in
-     * @return String containing all translated placeholders
-     */
-    public static String setBracketPlaceholders(OfflinePlayer player, String text) {
-        return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, true);
-    }
 
 	/**
 	 * Translates all placeholders into their corresponding values.
@@ -248,23 +395,14 @@ public class PlaceholderAPI {
 	 * @param text     Text to set the placeholder values in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return String containing all translated placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, String)} instead.
 	 */
-    public static String setBracketPlaceholders(OfflinePlayer player, String text, boolean colorize) {
+	@Deprecated
+	public static String setBracketPlaceholders(OfflinePlayer player, String text, boolean colorize)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, colorize);
 	}
 
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
-     *
-     * @param player Player to parse the placeholders against
-     * @param text   Text to set the placeholder values in
-     * @return String containing all translated placeholders
-     */
-    public static String setPlaceholders(OfflinePlayer player, String text) {
-        return setPlaceholders(player, text, PLACEHOLDER_PATTERN);
-    }
-
 	/**
 	 * Translates all placeholders into their corresponding values.
 	 * <br>The pattern of a valid placeholder is {@literal %<identifier>_<params>%}.
@@ -273,8 +411,11 @@ public class PlaceholderAPI {
 	 * @param text     Text to parse the placeholders in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return The text containing the parsed placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, String)} instead.
 	 */
-    public static String setPlaceholders(OfflinePlayer player, String text, boolean colorize) {
+	@Deprecated
+	public static String setPlaceholders(OfflinePlayer player, String text, boolean colorize)
+	{
 		return setPlaceholders(player, text, PLACEHOLDER_PATTERN, colorize);
 	}
 
@@ -287,60 +428,14 @@ public class PlaceholderAPI {
 	 * @param pattern The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
 	 *                identifier from the params
 	 * @return The text containing the parsed placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, String)} instead.
 	 */
-    public static String setPlaceholders(OfflinePlayer player, String text, Pattern pattern) {
+	@Deprecated
+	public static String setPlaceholders(OfflinePlayer player, String text, Pattern pattern)
+	{
 		return setPlaceholders(player, text, pattern, true);
 	}
 
-    /**
-     * Translates all placeholders into their corresponding values.
-     * <br>You set the pattern yourself through this method.
-     *
-     * @param player   Player to parse the placeholders against
-     * @param text     Text to set the placeholder values in
-     * @param pattern  The pattern to match placeholders to. Capture group 1 must contain an underscore separating the
-     *                 identifier from the params
-     * @param colorize If color codes (&[0-1a-fk-o]) should be translated
-     * @return The text containing the parsed placeholders
-     */
-    public static String setPlaceholders(OfflinePlayer player, String text, Pattern pattern, boolean colorize) {
-        if (text == null) {
-            return null;
-        }
-
-        if (placeholders.isEmpty()) {
-            return colorize ? color(text) : text;
-        }
-
-        final Matcher matcher = pattern.matcher(text);
-        final Map<String, PlaceholderHook> hooks = getPlaceholders();
-
-        while (matcher.find()) {
-            final String format = matcher.group(1);
-            final int index = format.indexOf("_");
-
-            if (index <= 0 || index >= format.length()) {
-                continue;
-            }
-
-            final String identifier = format.substring(0, index).toLowerCase();
-            final String params = format.substring(index + 1);
-            final PlaceholderHook hook = hooks.get(identifier);
-
-            if (hook == null) {
-                continue;
-            }
-
-            final String value = hook.onRequest(player, params);
-
-            if (value != null) {
-                text = text.replaceAll(Pattern.quote(matcher.group()), Matcher.quoteReplacement(value));
-            }
-        }
-
-        return colorize ? color(text) : text;
-    }
-
 	/**
 	 * Translate placeholders in the provided List based on the relation of the two provided players.
 	 * <br>The pattern of a valid placeholder is {@literal %rel_<identifier>_<param>%}.
@@ -349,8 +444,11 @@ public class PlaceholderAPI {
 	 * @param two  Player to compare
 	 * @param text text to parse the placeholder values to
 	 * @return The text containing the parsed relational placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, List)} instead.
 	 */
-    public static List<String> setRelationalPlaceholders(Player one, Player two, List<String> text) {
+	@Deprecated
+	public static List<String> setRelationalPlaceholders(Player one, Player two, List<String> text)
+	{
 		return setRelationalPlaceholders(one, two, text, true);
 	}
 
@@ -363,9 +461,13 @@ public class PlaceholderAPI {
 	 * @param text     Text to parse the placeholders in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return The text containing the parsed relational placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, List)} instead.
 	 */
-    public static List<String> setRelationalPlaceholders(Player one, Player two, List<String> text, boolean colorize) {
+	@Deprecated
-        if (text == null) {
+	public static List<String> setRelationalPlaceholders(Player one, Player two, List<String> text, boolean colorize)
+	{
+		if (text == null)
+		{
 			return null;
 		}
 
@@ -382,8 +484,11 @@ public class PlaceholderAPI {
 	 * @param two  Second player to compare
 	 * @param text Text to parse the placeholders in
 	 * @return The text containing the parsed relational placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, String)} instead.
 	 */
-    public static String setRelationalPlaceholders(Player one, Player two, String text) {
+	@Deprecated
+	public static String setRelationalPlaceholders(Player one, Player two, String text)
+	{
 		return setRelationalPlaceholders(one, two, text, true);
 	}
 
@@ -396,25 +501,32 @@ public class PlaceholderAPI {
 	 * @param text     Text to parse the placeholders in
 	 * @param colorize If color codes (&[0-1a-fk-o]) should be translated
 	 * @return The text containing the parsed relational placeholders
+	 * @deprecated Use {@link #setPlaceholders(OfflinePlayer, String)} instead.
 	 */
+	@Deprecated
 	@SuppressWarnings("DuplicatedCode")
-    public static String setRelationalPlaceholders(Player one, Player two, String text, boolean colorize) {
+	public static String setRelationalPlaceholders(Player one, Player two, String text, boolean colorize)
-        if (text == null) {
+	{
+		if (text == null)
+		{
 			return null;
 		}
 
-        if (placeholders.isEmpty()) {
+		if (PLACEHOLDERS.isEmpty())
+		{
 			return colorize ? Msg.color(text) : text;
 		}
 
 		final Matcher                      matcher = RELATIONAL_PLACEHOLDER_PATTERN.matcher(text);
 		final Map<String, PlaceholderHook> hooks   = getPlaceholders();
 
-        while (matcher.find()) {
+		while (matcher.find())
+		{
 			final String format = matcher.group(2);
 			final int    index  = format.indexOf("_");
 
-            if (index <= 0 || index >= format.length()) {
+			if (index <= 0 || index >= format.length())
+			{
 				continue;
 			}
 
@@ -422,13 +534,15 @@ public class PlaceholderAPI {
 			String                params     = format.substring(index + 1);
 			final PlaceholderHook hook       = hooks.get(identifier);
 
-            if (!(hook instanceof Relational)) {
+			if (!(hook instanceof Relational))
+			{
 				continue;
 			}
 
 			final String value = ((Relational) hook).onPlaceholderRequest(one, two, params);
 
-            if (value != null) {
+			if (value != null)
+			{
 				text = text.replaceAll(Pattern.quote(matcher.group()), Matcher.quoteReplacement(value));
 			}
 		}
@@ -436,60 +550,15 @@ public class PlaceholderAPI {
 		return colorize ? Msg.color(text) : text;
 	}
 
-    /**
-     * Unregister ALL placeholder hooks that are currently registered
-     */
-    protected static void unregisterAll() {
-        unregisterAllProvidedExpansions();
-        placeholders.clear();
-    }
-
-    /**
-     * Unregister all expansions provided by PlaceholderAPI
-     */
-    public static void unregisterAllProvidedExpansions() {
-        final Set<PlaceholderHook> set = new HashSet<>(placeholders.values());
-
-        for (PlaceholderHook hook : set) {
-            if (hook instanceof PlaceholderExpansion) {
-                final PlaceholderExpansion expansion = (PlaceholderExpansion) hook;
-
-                if (!expansion.persist()) {
-                    unregisterExpansion(expansion);
-                }
-            }
-
-            if (hook instanceof Cacheable) {
-                ((Cacheable) hook).clear();
-            }
-        }
-    }
-
-    public static boolean registerExpansion(PlaceholderExpansion ex) {
-        ExpansionRegisterEvent ev = new ExpansionRegisterEvent(ex);
-        Bukkit.getPluginManager().callEvent(ev);
-        if (ev.isCancelled()) {
-            return false;
-        }
-
-        return registerPlaceholderHook(ex.getIdentifier(), ex);
-    }
-
-    public static boolean unregisterExpansion(PlaceholderExpansion ex) {
-        if (unregisterPlaceholderHook(ex.getIdentifier())) {
-            Bukkit.getPluginManager().callEvent(new ExpansionUnregisterEvent(ex));
-            return true;
-        }
-
-        return false;
-    }
-
 	/**
 	 * Gets the placeholder pattern for the default placeholders.
 	 *
 	 * @return The pattern for {@literal %<identifier>_<params>%}
+	 * @deprecated Will be removed in a future release.
 	 */
-    public static Pattern getPlaceholderPattern() {
+	@Deprecated
+	public static Pattern getPlaceholderPattern()
+	{
 		return PLACEHOLDER_PATTERN;
 	}
 
@@ -497,8 +566,11 @@ public class PlaceholderAPI {
 	 * Gets the placeholder pattern for the bracket placeholders.
 	 *
 	 * @return The pattern for {@literal {<identifier>_<params>}}
+	 * @deprecated Will be removed in a future release.
 	 */
-    public static Pattern getBracketPlaceholderPattern() {
+	@Deprecated
+	public static Pattern getBracketPlaceholderPattern()
+	{
 		return BRACKET_PLACEHOLDER_PATTERN;
 	}
 
@@ -506,60 +578,93 @@ public class PlaceholderAPI {
 	 * Gets the placeholder pattern for the relational placeholders.
 	 *
 	 * @return The pattern for {@literal %rel_<identifier>_<params>%}
+	 * @deprecated Will be removed in a future release.
 	 */
-    public static Pattern getRelationalPlaceholderPattern() {
+	@Deprecated
+	public static Pattern getRelationalPlaceholderPattern()
+	{
 		return RELATIONAL_PLACEHOLDER_PATTERN;
 	}
 
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
 	@Deprecated
-    public static Set<String> getRegisteredPlaceholderPlugins() {
+	public static Set<String> getRegisteredPlaceholderPlugins()
+	{
 		return getRegisteredIdentifiers();
 	}
 
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
 	@Deprecated
-    public static Set<String> getExternalPlaceholderPlugins() {
+	public static Set<String> getExternalPlaceholderPlugins()
+	{
 		return null;
 	}
 
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
 	@Deprecated
-    public static boolean registerPlaceholderHook(Plugin plugin, PlaceholderHook placeholderHook) {
+	public static String setPlaceholders(Player player, String text, boolean colorize)
-        return plugin != null && registerPlaceholderHook(plugin.getName(), placeholderHook);
+	{
-    }
-
-    @Deprecated
-    public static boolean unregisterPlaceholderHook(Plugin plugin) {
-        return plugin != null && unregisterPlaceholderHook(plugin.getName());
-    }
-
-    public static String setPlaceholders(Player player, String text) {
-        return setPlaceholders(player, text, PLACEHOLDER_PATTERN, true);
-    }
-
-    public static String setPlaceholders(Player player, String text, boolean colorize) {
 		return setPlaceholders(player, text, PLACEHOLDER_PATTERN, colorize);
 	}
 
-    public static List<String> setPlaceholders(Player player, List<String> text) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static List<String> setPlaceholders(Player player, List<String> text)
+	{
 		return setPlaceholders(player, text, PLACEHOLDER_PATTERN, true);
 	}
 
-    public static List<String> setPlaceholders(Player player, List<String> text, boolean colorize) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static List<String> setPlaceholders(Player player, List<String> text, boolean colorize)
+	{
 		return setPlaceholders(player, text, PLACEHOLDER_PATTERN, colorize);
 	}
 
-    public static String setBracketPlaceholders(Player player, String text) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static String setBracketPlaceholders(Player player, String text)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, true);
 	}
 
-    public static String setBracketPlaceholders(Player player, String text, boolean colorize) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static String setBracketPlaceholders(Player player, String text, boolean colorize)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, colorize);
 	}
 
-    public static List<String> setBracketPlaceholders(Player player, List<String> text) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static List<String> setBracketPlaceholders(Player player, List<String> text)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, true);
 	}
 
-    public static List<String> setBracketPlaceholders(Player player, List<String> text, boolean colorize) {
+	/**
+	 * @deprecated Will be removed in a future release.
+	 */
+	@Deprecated
+	public static List<String> setBracketPlaceholders(Player player, List<String> text, boolean colorize)
+	{
 		return setPlaceholders(player, text, BRACKET_PLACEHOLDER_PATTERN, colorize);
 	}
+
 }

src/main/java/me/clip/placeholderapi/PlaceholderHook.java

@@ -22,8 +22,11 @@ package me.clip.placeholderapi;
 
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
-public abstract class PlaceholderHook {
+public abstract class PlaceholderHook
+{
 
 	/**
 	 * called when a placeholder value is requested from this hook
@@ -33,8 +36,11 @@ public abstract class PlaceholderHook {
 	 * @param params String passed to the hook to determine what value to return
 	 * @return value for the requested player and params
 	 */
-    public String onRequest(OfflinePlayer player, String params) {
+	@Nullable
-        if (player != null && player.isOnline()) {
+	public String onRequest(@Nullable final OfflinePlayer player, @NotNull final String params)
+	{
+		if (player != null && player.isOnline())
+		{
 			return onPlaceholderRequest((Player) player, params);
 		}
 
@@ -48,7 +54,11 @@ public abstract class PlaceholderHook {
 	 * @param params String passed to the hook to determine what value to return
 	 * @return value for the requested player and params
 	 */
-    public String onPlaceholderRequest(Player player, String params) {
+	@Nullable
+	@Deprecated
+	public String onPlaceholderRequest(@Nullable final Player player, @NotNull final String params)
+	{
 		return null;
 	}
+
 }

src/main/java/me/clip/placeholderapi/expansion/ExpansionManager.java

@@ -28,29 +28,42 @@ import me.clip.placeholderapi.util.FileUtil;
 import org.bukkit.Bukkit;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.event.Listener;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
-import java.lang.reflect.Constructor;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.logging.Level;
 
-public final class ExpansionManager {
+public final class ExpansionManager
+{
+
+	@NotNull
+	private final File                 folder;
+	@NotNull
 	private final PlaceholderAPIPlugin plugin;
 
-    public ExpansionManager(PlaceholderAPIPlugin instance) {
+	public ExpansionManager(@NotNull final PlaceholderAPIPlugin plugin)
-        plugin = instance;
+	{
+		this.plugin = plugin;
+		this.folder = new File(plugin.getDataFolder(), "expansions");
 
-        File f = new File(PlaceholderAPIPlugin.getInstance().getDataFolder(), "expansions");
+		if (!this.folder.exists() && !folder.mkdirs())
-        if (!f.exists()) {
+		{
-            f.mkdirs();
+			plugin.getLogger().log(Level.WARNING, "failed to create expansions folder!");
 		}
 	}
 
-    public PlaceholderExpansion getRegisteredExpansion(String name) {
+	public PlaceholderExpansion getRegisteredExpansion(String name)
-        for (Entry<String, PlaceholderHook> hook : PlaceholderAPI.getPlaceholders().entrySet()) {
+	{
-            if (hook.getValue() instanceof PlaceholderExpansion) {
+		for (Entry<String, PlaceholderHook> hook : PlaceholderAPI.getPlaceholders().entrySet())
-                if (name.equalsIgnoreCase(hook.getKey())) {
+		{
+			if (hook.getValue() instanceof PlaceholderExpansion)
+			{
+				if (name.equalsIgnoreCase(hook.getKey()))
+				{
 					return (PlaceholderExpansion) hook.getValue();
 				}
 			}
@@ -59,30 +72,41 @@ public final class ExpansionManager {
 		return null;
 	}
 
-    public boolean registerExpansion(PlaceholderExpansion expansion) {
+	public boolean registerExpansion(@NotNull final PlaceholderExpansion expansion)
-        if (expansion == null || expansion.getIdentifier() == null) {
+	{
+		if (expansion.getIdentifier() == null)
+		{
 			return false;
 		}
 
-        if (expansion instanceof Configurable) {
+		if (expansion instanceof Configurable)
+		{
 			Map<String, Object> defaults = ((Configurable) expansion).getDefaults();
 			String              pre      = "expansions." + expansion.getIdentifier() + ".";
 			FileConfiguration   cfg      = plugin.getConfig();
 			boolean             save     = false;
 
-            if (defaults != null) {
+			if (defaults != null)
-                for (Entry<String, Object> entries : defaults.entrySet()) {
+			{
-                    if (entries.getKey() == null || entries.getKey().isEmpty()) {
+				for (Entry<String, Object> entries : defaults.entrySet())
+				{
+					if (entries.getKey() == null || entries.getKey().isEmpty())
+					{
 						continue;
 					}
 
-                    if (entries.getValue() == null) {
+					if (entries.getValue() == null)
-                        if (cfg.contains(pre + entries.getKey())) {
+					{
+						if (cfg.contains(pre + entries.getKey()))
+						{
 							save = true;
 							cfg.set(pre + entries.getKey(), null);
 						}
-                    } else {
+					}
-                        if (!cfg.contains(pre + entries.getKey())) {
+					else
+					{
+						if (!cfg.contains(pre + entries.getKey()))
+						{
 							save = true;
 							cfg.set(pre + entries.getKey(), entries.getValue());
 						}
@@ -90,15 +114,18 @@ public final class ExpansionManager {
 				}
 			}
 
-            if (save) {
+			if (save)
+			{
 				plugin.saveConfig();
 				plugin.reloadConfig();
 			}
 		}
 
-        if (expansion instanceof VersionSpecific) {
+		if (expansion instanceof VersionSpecific)
+		{
 			VersionSpecific nms = (VersionSpecific) expansion;
-            if (!nms.isCompatibleWith(PlaceholderAPIPlugin.getServerVersion())) {
+			if (!nms.isCompatibleWith(PlaceholderAPIPlugin.getServerVersion()))
+			{
 				plugin.getLogger()
 					  .info(
 							  "Your server version is not compatible with expansion: " + expansion.getIdentifier()
@@ -107,32 +134,33 @@ public final class ExpansionManager {
 			}
 		}
 
-        if (!expansion.canRegister()) {
+		if (!expansion.canRegister() || !expansion.register())
+		{
 			return false;
 		}
 
-        if (!expansion.register()) {
+		if (expansion instanceof Listener)
-            return false;
+		{
-        }
+			Bukkit.getPluginManager().registerEvents(((Listener) expansion), plugin);
-
-        if (expansion instanceof Listener) {
-            Listener l = (Listener) expansion;
-            Bukkit.getPluginManager().registerEvents(l, plugin);
 		}
 
 		plugin.getLogger().info("Successfully registered expansion: " + expansion.getIdentifier());
 
-        if (expansion instanceof Taskable) {
+		if (expansion instanceof Taskable)
+		{
 			((Taskable) expansion).start();
 		}
 
-        if (plugin.getExpansionCloud() != null) {
+		if (plugin.getExpansionCloud() != null)
-            CloudExpansion ce = plugin.getExpansionCloud().getCloudExpansion(expansion.getIdentifier());
+		{
+			final CloudExpansion cloudExpansion = plugin.getExpansionCloud().getCloudExpansion(expansion.getIdentifier());
 
-            if (ce != null) {
+			if (cloudExpansion != null)
-                ce.setHasExpansion(true);
+			{
-                if (!ce.getLatestVersion().equals(expansion.getVersion())) {
+				cloudExpansion.setHasExpansion(true);
-                    ce.setShouldUpdate(true);
+				if (!cloudExpansion.getLatestVersion().equals(expansion.getVersion()))
+				{
+					cloudExpansion.setShouldUpdate(true);
 				}
 			}
 		}
@@ -141,73 +169,66 @@ public final class ExpansionManager {
 	}
 
 
-    public PlaceholderExpansion registerExpansion(String fileName) {
+	@Nullable
-        List<Class<?>> subs = FileUtil.getClasses("expansions", fileName, PlaceholderExpansion.class);
+	public PlaceholderExpansion registerExpansion(@NotNull final String fileName)
-        if (subs == null || subs.isEmpty()) {
+	{
+		final List<Class<? extends PlaceholderExpansion>> subs = FileUtil.getClasses(folder, PlaceholderExpansion.class, fileName);
+		if (subs.isEmpty())
+		{
 			return null;
 		}
 
 		// only register the first instance found as an expansion jar should only have 1 class
 		// extending PlaceholderExpansion
-        PlaceholderExpansion ex = createInstance(subs.get(0));
+		final PlaceholderExpansion expansion = createInstance(subs.get(0));
-        if (registerExpansion(ex)) {
+		if (expansion != null && registerExpansion(expansion))
-            return ex;
+		{
+			return expansion;
 		}
 
 		return null;
 	}
 
-    public void registerAllExpansions() {
+	public void registerAllExpansions()
-        if (plugin == null) {
+	{
+		final List<@NotNull Class<? extends PlaceholderExpansion>> subs = FileUtil.getClasses(folder, PlaceholderExpansion.class);
+		if (subs.isEmpty())
+		{
 			return;
 		}
 
-        List<Class<?>> subs = FileUtil.getClasses("expansions", null, PlaceholderExpansion.class);
+		for (final Class<? extends PlaceholderExpansion> clazz : subs)
-        if (subs == null || subs.isEmpty()) {
+		{
-            return;
+			final PlaceholderExpansion expansion = createInstance(clazz);
+			if (expansion == null)
+			{
+				continue;
 			}
 
-        for (Class<?> klass : subs) {
+			try
-            PlaceholderExpansion ex = createInstance(klass);
+			{
-            if (ex != null) {
+				registerExpansion(expansion);
-                try {
-                    registerExpansion(ex);
-                } catch (Exception e) {
-                    plugin.getLogger().info("Couldn't register " + ex.getIdentifier() + " expansion");
-                    e.printStackTrace();
 			}
+			catch (final Exception ex)
+			{
+				plugin.getLogger().log(Level.WARNING, "Couldn't register " + expansion.getIdentifier() + " expansion", ex);
 			}
 		}
 	}
 
-    private PlaceholderExpansion createInstance(Class<?> klass) {
+	@Nullable
-        if (klass == null) {
+	private PlaceholderExpansion createInstance(@NotNull final Class<? extends PlaceholderExpansion> clazz)
+	{
+		try
+		{
+			return clazz.getDeclaredConstructor().newInstance();
+		}
+		catch (final Throwable ex)
+		{
+			plugin.getLogger().log(Level.SEVERE, "Failed to load placeholder expansion from class: " + clazz.getName(), ex);
+		}
+
 		return null;
 	}
 
-        PlaceholderExpansion ex = null;
-        if (!PlaceholderExpansion.class.isAssignableFrom(klass)) {
-            return null;
-        }
-
-        try {
-            Constructor<?>[] c = klass.getConstructors();
-            if (c.length == 0) {
-                ex = (PlaceholderExpansion) klass.newInstance();
-            } else {
-                for (Constructor<?> con : c) {
-                    if (con.getParameterTypes().length == 0) {
-                        ex = (PlaceholderExpansion) klass.newInstance();
-                        break;
-                    }
-                }
-            }
-        } catch (Throwable t) {
-            plugin.getLogger()
-                    .severe("Failed to init placeholder expansion from class: " + klass.getName());
-            plugin.getLogger().severe(t.getMessage());
-        }
-
-        return ex;
-    }
 }

src/main/java/me/clip/placeholderapi/replacer/CharsReplacer.java

@@ -0,0 +1,129 @@
+package me.clip.placeholderapi.replacer;
+
+import me.clip.placeholderapi.PlaceholderHook;
+import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.Function;
+
+public final class CharsReplacer implements Replacer
+{
+
+	@NotNull
+	private final Closure closure;
+
+	public CharsReplacer(@NotNull final Closure closure)
+	{
+		this.closure = closure;
+	}
+
+
+	@Override
+	public @NotNull String apply(@NotNull final String text, @Nullable final OfflinePlayer player, @NotNull final Function<String, @Nullable PlaceholderHook> lookup)
+	{
+		final char[]        chars   = text.toCharArray();
+		final StringBuilder builder = new StringBuilder(text.length());
+
+		final StringBuilder identifier = new StringBuilder();
+		final StringBuilder parameters = new StringBuilder();
+
+		for (int i = 0; i < chars.length; i++)
+		{
+			final char l = chars[i];
+
+			if (l == '&' && ++i < chars.length)
+			{
+				final char c = chars[i];
+
+				if (c != '0' && c != '1' && c != '2' && c != '3' && c != '4' && c != '5' && c != '6' && c != '7' && c != '8' && c != '9' && c != 'a' && c != 'b' && c != 'c' && c != 'd' && c != 'e' && c != 'f' && c != 'k' && c != 'l' && c != 'm' && c != 'o' && c != 'r' && c != 'x')
+				{
+					builder.append(l).append(c);
+				}
+				else
+				{
+					builder.append('§').append(c);
+				}
+				continue;
+			}
+
+			if (l != closure.head || i + 1 >= chars.length)
+			{
+				builder.append(l);
+				continue;
+			}
+
+			boolean identified = false;
+			boolean oopsitsbad = false;
+
+			while (++i < chars.length)
+			{
+				final char p = chars[i];
+
+				if (p == closure.tail)
+				{
+					break;
+				}
+
+				if (p == ' ')
+				{
+					oopsitsbad = true;
+					break;
+				}
+
+				if (p == '_' && !identified)
+				{
+					identified = true;
+					continue;
+				}
+
+				if (identified)
+				{
+					parameters.append(p);
+				}
+				else
+				{
+					identifier.append(p);
+				}
+			}
+
+			final String identifierString = identifier.toString();
+			final String parametersString = parameters.toString();
+
+			identifier.setLength(0);
+			parameters.setLength(0);
+
+			if (oopsitsbad)
+			{
+				builder.append(closure.head).append(identifierString);
+
+				if (identified)
+				{
+					builder.append('_').append(parametersString);
+				}
+
+				builder.append(' ');
+				continue;
+			}
+
+			final PlaceholderHook placeholder = lookup.apply(identifierString);
+			if (placeholder == null)
+			{
+				builder.append(closure.head).append(identifierString).append('_').append(parametersString).append(closure.tail);
+				continue;
+			}
+
+			final String replacement = placeholder.onRequest(player, parametersString);
+			if (replacement == null)
+			{
+				builder.append(closure.head).append(identifierString).append('_').append(parametersString).append(closure.tail);
+				continue;
+			}
+
+			builder.append(replacement);
+		}
+
+		return builder.toString();
+	}
+
+}

src/main/java/me/clip/placeholderapi/replacer/RegexReplacer.java

@@ -0,0 +1,55 @@
+package me.clip.placeholderapi.replacer;
+
+import me.clip.placeholderapi.PlaceholderHook;
+import org.bukkit.ChatColor;
+import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public final class RegexReplacer implements Replacer
+{
+
+	@NotNull
+	private final Pattern pattern;
+
+	public RegexReplacer(@NotNull final Closure closure)
+	{
+		this.pattern = Pattern.compile(String.format("\\%s((?<identifier>[a-zA-Z0-9]+)_)(?<parameters>[^%s%s]+)\\%s", closure.head, closure.head, closure.tail, closure.tail));
+	}
+
+
+	@Override
+	public @NotNull String apply(@NotNull final String text, @Nullable final OfflinePlayer player, @NotNull final Function<String, @Nullable PlaceholderHook> lookup)
+	{
+		final Matcher matcher = pattern.matcher(text);
+		if (!matcher.find())
+		{
+			return text;
+		}
+
+		final StringBuffer builder = new StringBuffer();
+
+		do
+		{
+			final String identifier = matcher.group("identifier");
+			final String parameters = matcher.group("parameters");
+
+			final PlaceholderHook hook = lookup.apply(identifier);
+			if (hook == null)
+			{
+				continue;
+			}
+
+			final String requested = hook.onRequest(player, parameters);
+			matcher.appendReplacement(builder, requested != null ? requested : matcher.group(0));
+		}
+		while (matcher.find());
+
+		return ChatColor.translateAlternateColorCodes('&', matcher.appendTail(builder).toString());
+	}
+
+}

src/main/java/me/clip/placeholderapi/replacer/Replacer.java

@@ -0,0 +1,32 @@
+package me.clip.placeholderapi.replacer;
+
+import me.clip.placeholderapi.PlaceholderHook;
+import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.Function;
+
+public interface Replacer
+{
+
+	@NotNull
+	String apply(@NotNull final String text, @Nullable final OfflinePlayer player, @NotNull final Function<String, @Nullable PlaceholderHook> lookup);
+
+
+	enum Closure
+	{
+		BRACKET('{', '}'),
+		PERCENT('%', '%');
+
+
+		public final char head, tail;
+
+		Closure(final char head, final char tail)
+		{
+			this.head = head;
+			this.tail = tail;
+		}
+	}
+
+}

src/main/java/me/clip/placeholderapi/util/FileUtil.java

@@ -20,89 +20,85 @@
  */
 package me.clip.placeholderapi.util;
 
-import me.clip.placeholderapi.PlaceholderAPIPlugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.io.FilenameFilter;
+import java.io.IOException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarInputStream;
 
-public class FileUtil {
+public class FileUtil
+{
 
-    public static List<Class<?>> getClasses(String folder, Class<?> type) {
+	@NotNull
-        return getClasses(folder, null, type);
+	public static <T> List<@NotNull Class<? extends T>> getClasses(@NotNull final File folder, @NotNull final Class<T> clazz)
+	{
+		return getClasses(folder, clazz, null);
 	}
 
-    public static List<Class<?>> getClasses(String folder, String fileName, Class<?> type) {
+	@NotNull
-        List<Class<?>> list = new ArrayList<>();
+	public static <T> List<@NotNull Class<? extends T>> getClasses(@NotNull final File folder, @NotNull final Class<T> clazz, @Nullable final String target)
-
+	{
-        try {
+		if (!folder.exists())
-            File f = new File(PlaceholderAPIPlugin.getInstance().getDataFolder(), folder);
+		{
-            if (!f.exists()) {
+			return Collections.emptyList();
-                return list;
 		}
 
-            FilenameFilter fileNameFilter = (dir, name) -> {
+		try
-                if (fileName != null) {
+		{
-                    return name.endsWith(".jar") && name.replace(".jar", "")
+			final FilenameFilter filter =
-                            .equalsIgnoreCase(fileName.replace(".jar", ""));
+					(dir, name) -> name.endsWith(".jar") && (target == null || name.replace(".jar", "").equalsIgnoreCase(target.replace(".jar", "")));
+
+			final File[] jars = folder.listFiles(filter);
+			if (jars == null)
+			{
+				return Collections.emptyList();
 			}
 
-                return name.endsWith(".jar");
+			final List<@NotNull Class<? extends T>> list = new ArrayList<>();
-            };
 
-            File[] jars = f.listFiles(fileNameFilter);
+			for (File file : jars)
-            if (jars == null) {
+			{
-                return list;
+				gather(file.toURI().toURL(), clazz, list);
-            }
-
-            for (File file : jars) {
-                list = gather(file.toURI().toURL(), list, type);
 			}
 
 			return list;
-        } catch (Throwable t) {
+		}
+		catch (Throwable t)
+		{
+			// THIS SHOULD NOT BE EATEN LIKE THIS.
 		}
 
-        return null;
+		return Collections.emptyList();
 	}
 
-    private static List<Class<?>> gather(URL jar, List<Class<?>> list, Class<?> clazz) {
+	private static <T> void gather(@NotNull final URL jar, @NotNull final Class<T> clazz, @NotNull final List<@NotNull Class<? extends T>> list) throws IOException, ClassNotFoundException
-        if (list == null) {
+	{
-            list = new ArrayList<>();
+		try (final URLClassLoader loader = new URLClassLoader(new URL[]{jar}, clazz.getClassLoader()); final JarInputStream stream = new JarInputStream(jar.openStream()))
-        }
+		{
-
+			JarEntry entry;
-        try (URLClassLoader cl = new URLClassLoader(new URL[]{jar}, clazz.getClassLoader());
+			while ((entry = stream.getNextJarEntry()) != null)
-             JarInputStream jis = new JarInputStream(jar.openStream())) {
+			{
-
+				final String name = entry.getName();
-            while (true) {
+				if (name == null || name.isEmpty() || !name.endsWith(".class"))
-                JarEntry j = jis.getNextJarEntry();
+				{
-                if (j == null) {
-                    break;
-                }
-
-                String name = j.getName();
-                if (name == null || name.isEmpty()) {
 					continue;
 				}
 
-                if (name.endsWith(".class")) {
+				final Class<?> loaded = loader.loadClass(name.substring(0, name.lastIndexOf('.')).replace('/', '.'));
-                    name = name.replace("/", ".");
+				if (clazz.isAssignableFrom(loaded))
-                    String cname = name.substring(0, name.lastIndexOf(".class"));
+				{
-
+					list.add(loaded.asSubclass(clazz));
-                    Class<?> c = cl.loadClass(cname);
-                    if (clazz.isAssignableFrom(c)) {
-                        list.add(c);
 				}
 			}
 		}
-        } catch (Throwable t) {
 	}
 
-        return list;
-    }
 }

src/main/java/me/clip/placeholderapi/util/Msg.java

@@ -23,21 +23,37 @@ package me.clip.placeholderapi.util;
 import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Arrays;
-import java.util.Objects;
 import java.util.stream.Collectors;
 
-public final class Msg {
+public final class Msg
-    public static void msg(CommandSender s, String... msg) {
+{
-        s.sendMessage(Arrays.stream(msg).filter(Objects::nonNull).map(Msg::color).collect(Collectors.joining("\n")));
+
+	public static void msg(@NotNull final CommandSender sender, @NotNull final String... messages)
+	{
+		if (messages.length == 0)
+		{
+			return;
 		}
 
-    public static void broadcast(String... msg) {
+		sender.sendMessage(Arrays.stream(messages).map(Msg::color).collect(Collectors.joining("\n")));
-        Arrays.stream(msg).filter(Objects::nonNull).map(Msg::color).forEach(Bukkit::broadcastMessage);
 	}
 
-    public static String color(String text) {
+	public static void broadcast(@NotNull final String... messages)
+	{
+		if (messages.length == 0)
+		{
+			return;
+		}
+
+		Bukkit.broadcastMessage(Arrays.stream(messages).map(Msg::color).collect(Collectors.joining("\n")));
+	}
+
+	public static String color(@NotNull final String text)
+	{
 		return ChatColor.translateAlternateColorCodes('&', text);
 	}
+
 }

src/test/java/me/clip/placeholderapi/Values.java

@@ -0,0 +1,187 @@
+package me.clip.placeholderapi;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import me.clip.placeholderapi.replacer.CharsReplacer;
+import me.clip.placeholderapi.replacer.RegexReplacer;
+import me.clip.placeholderapi.replacer.Replacer;
+import org.bukkit.ChatColor;
+import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Set;
+import java.util.function.Function;
+
+public interface Values
+{
+
+	String SMALL_TEXT = "My name is %player_name%";
+	String LARGE_TEXT = "My name is %player_name% and my location is (%player_x%, %player_y%, %player_z%), this placeholder is invalid %server_name%";
+
+	ImmutableMap<String, PlaceholderHook> PLACEHOLDERS = ImmutableMap.<String, PlaceholderHook>builder()
+			.put("player", new MockPlayerPlaceholderHook())
+			.build();
+
+
+	Replacer CHARS_REPLACER = new CharsReplacer(Replacer.Closure.PERCENT);
+	Replacer REGEX_REPLACER = new RegexReplacer(Replacer.Closure.PERCENT);
+	Replacer TESTS_REPLACER = new Replacer()
+	{
+		private final Set<Character> COLOR_CODES = ImmutableSet.of('0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+																		  'a', 'b', 'c', 'd', 'e', 'f', 'k', 'l', 'm', 'o', 'r', 'x');
+
+		private final boolean colorize = true;
+		private final Replacer.Closure closure = Replacer.Closure.PERCENT;
+
+		@Override
+		public @NotNull String apply(final @NotNull String text, final @Nullable OfflinePlayer player, final @NotNull Function<String, @Nullable PlaceholderHook> lookup)
+		{
+			char[]        chars   = text.toCharArray();
+			StringBuilder builder = new StringBuilder(chars.length);
+
+			// This won't cause memory leaks. It's inside a method. And we want to use setLength instead of
+			// creating a new string builder to use the maximum capacity and avoid initializing new objects.
+			StringBuilder   identifier = new StringBuilder(50);
+			PlaceholderHook handler    = null;
+
+			// Stages:
+			//   Stage -1: Look for the color code in the next character.
+			//   Stage 0: No closures detected, or the detected identifier is invalid. We're going forward while appending the characters normally.
+			//   Stage 1: The closure has been detected, looking for the placeholder identifier...
+			//   Stage 2: Detected the identifier and the parameter. Translating the placeholder...
+			int stage = 0;
+
+			for (char ch : chars)
+			{
+				if (stage == -1 && COLOR_CODES.contains(ch))
+				{
+					builder.append(ChatColor.COLOR_CHAR).append(ch);
+					stage = 0;
+					continue;
+				}
+
+				// Check if the placeholder starts or ends.
+				if (ch == closure.head || ch == closure.tail)
+				{
+					// If the placeholder ends.
+					if (stage == 2)
+					{
+						String parameter  = identifier.toString();
+						String translated = handler.onRequest(player, parameter);
+
+						if (translated == null)
+						{
+							String name = "";
+							builder.append(closure.head).append(name).append('_').append(parameter).append(closure.tail);
+						}
+						else
+						{
+							builder.append(translated);
+						}
+
+						identifier.setLength(0);
+						stage = 0;
+						continue;
+					}
+					else if (stage == 1)
+					{ // If it just started | Double closures | If it's still hasn't detected the indentifier, reset.
+						builder.append(closure.head).append(identifier);
+					}
+
+					identifier.setLength(0);
+					stage = 1;
+					continue;
+				}
+
+				// Placeholder identifier started.
+				if (stage == 1)
+				{
+					// Compare the current character with the idenfitier's.
+					// We reached the end of our identifier.
+					if (ch == '_')
+					{
+						handler = lookup.apply(identifier.toString());
+						if (handler == null)
+						{
+							builder.append(closure.head).append(identifier).append('_');
+							stage = 0;
+						}
+						else
+						{
+							identifier.setLength(0);
+							stage = 2;
+						}
+						continue;
+					}
+
+					// Keep building the identifier name.
+					identifier.append(ch);
+					continue;
+				}
+
+				// Building the placeholder parameter.
+				if (stage == 2)
+				{
+					identifier.append(ch);
+					continue;
+				}
+
+				// Nothing placeholder related was found.
+				if (colorize && ch == '&')
+				{
+					stage = -1;
+					continue;
+				}
+				builder.append(ch);
+			}
+
+			if (identifier != null)
+			{
+				if (stage > 0)
+				{
+					builder.append(closure.tail);
+				}
+				builder.append(identifier);
+			}
+			return builder.toString();
+		}
+	};
+
+
+	final class MockPlayerPlaceholderHook extends PlaceholderHook
+	{
+
+		public static final String PLAYER_X    = String.valueOf(10);
+		public static final String PLAYER_Y    = String.valueOf(20);
+		public static final String PLAYER_Z    = String.valueOf(30);
+		public static final String PLAYER_NAME = "Sxtanna";
+
+
+		@Override
+		public String onRequest(final OfflinePlayer player, final String params)
+		{
+			final String[] parts = params.split("_");
+			if (parts.length == 0)
+			{
+				return null;
+			}
+
+			switch (parts[0])
+			{
+				case "name":
+					return PLAYER_NAME;
+				case "x":
+					return PLAYER_X;
+				case "y":
+					return PLAYER_Y;
+				case "z":
+					return PLAYER_Z;
+			}
+
+			return null;
+		}
+
+	}
+
+}

src/test/java/me/clip/placeholderapi/replacer/ReplacerBenchmarks.java

@@ -0,0 +1,45 @@
+package me.clip.placeholderapi.replacer;
+
+import me.clip.placeholderapi.Values;
+import org.openjdk.jmh.annotations.Benchmark;
+
+public class ReplacerBenchmarks
+{
+
+	@Benchmark
+	public void measureCharsReplacerSmallText()
+	{
+		Values.CHARS_REPLACER.apply(Values.SMALL_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+	@Benchmark
+	public void measureRegexReplacerSmallText()
+	{
+		Values.REGEX_REPLACER.apply(Values.SMALL_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+	@Benchmark
+	public void measureCharsReplacerLargeText()
+	{
+		Values.CHARS_REPLACER.apply(Values.LARGE_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+	@Benchmark
+	public void measureRegexReplacerLargeText()
+	{
+		Values.REGEX_REPLACER.apply(Values.LARGE_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+	@Benchmark
+	public void measureTestsReplacerSmallText()
+	{
+		Values.TESTS_REPLACER.apply(Values.SMALL_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+	@Benchmark
+	public void measureTestsReplacerLargeText()
+	{
+		Values.TESTS_REPLACER.apply(Values.LARGE_TEXT, null, Values.PLACEHOLDERS::get);
+	}
+
+}

src/test/java/me/clip/placeholderapi/replacer/ReplacerUnitTester.java

@@ -0,0 +1,67 @@
+package me.clip.placeholderapi.replacer;
+
+import me.clip.placeholderapi.Values;
+import org.junit.jupiter.api.Test;
+
+import static me.clip.placeholderapi.Values.MockPlayerPlaceholderHook.PLAYER_NAME;
+import static me.clip.placeholderapi.Values.MockPlayerPlaceholderHook.PLAYER_X;
+import static me.clip.placeholderapi.Values.MockPlayerPlaceholderHook.PLAYER_Y;
+import static me.clip.placeholderapi.Values.MockPlayerPlaceholderHook.PLAYER_Z;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public final class ReplacerUnitTester
+{
+
+	@Test
+	void testCharsReplacerProducesExpectedSingleValue()
+	{
+		assertEquals(PLAYER_NAME, Values.CHARS_REPLACER.apply("%player_name%", null, Values.PLACEHOLDERS::get));
+	}
+
+	@Test
+	void testRegexReplacerProducesExpectedSingleValue()
+	{
+		assertEquals(PLAYER_NAME, Values.REGEX_REPLACER.apply("%player_name%", null, Values.PLACEHOLDERS::get));
+	}
+
+	@Test
+	void testCharsReplacerProducesExpectedSentence()
+	{
+		assertEquals(String.format("My name is %s and my location is (%s, %s, %s), this placeholder is invalid %%server_name%%", PLAYER_NAME, PLAYER_X, PLAYER_Y, PLAYER_Z), Values.CHARS_REPLACER.apply(Values.LARGE_TEXT, null, Values.PLACEHOLDERS::get));
+	}
+
+	@Test
+	void testRegexReplacerProducesExpectedSentence()
+	{
+		assertEquals(String.format("My name is %s and my location is (%s, %s, %s), this placeholder is invalid %%server_name%%", PLAYER_NAME, PLAYER_X, PLAYER_Y, PLAYER_Z), Values.REGEX_REPLACER.apply(Values.LARGE_TEXT, null, Values.PLACEHOLDERS::get));
+	}
+
+	@Test
+	void testResultsAreTheSameAsReplacement()
+	{
+		final String resultChars = Values.CHARS_REPLACER.apply("%player_name%", null, Values.PLACEHOLDERS::get);
+		final String resultRegex = Values.REGEX_REPLACER.apply("%player_name%", null, Values.PLACEHOLDERS::get);
+
+		assertEquals(resultChars, resultRegex);
+
+		assertEquals(PLAYER_NAME, resultChars);
+	}
+
+	@Test
+	void testResultsAreTheSameNoReplacement()
+	{
+		final String resultChars = Values.CHARS_REPLACER.apply("%player_location%", null, Values.PLACEHOLDERS::get);
+		final String resultRegex = Values.REGEX_REPLACER.apply("%player_location%", null, Values.PLACEHOLDERS::get);
+
+		assertEquals(resultChars, resultRegex);
+	}
+
+	@Test
+	void testCharsReplacerIgnoresMalformed()
+	{
+		final String text = "10% and %hello world 15%";
+
+		assertEquals(text, Values.CHARS_REPLACER.apply(text, null, Values.PLACEHOLDERS::get));
+	}
+
+}