1 files changed, 49 insertions, 0 deletions
diff --git a/src/main/java/org/bukkit/util/StringUtil.java b/src/main/java/org/bukkit/util/StringUtil.java
new file mode 100644
index 00000000..12bc58d4
--- /dev/null
+++ b/src/main/java/org/bukkit/util/StringUtil.java
@@ -0,0 +1,49 @@
+package org.bukkit.util;
+
+import java.util.Collection;
+import org.apache.commons.lang.Validate;
+
+public class StringUtil {
+
+    /**
+     * Copies all elements from the iterable collection of originals to the collection provided.
+     *
+     * @param token String to search for
+     * @param originals An iterable collection of strings to filter.
+     * @param collection The collection to add matches to
+     * @return the collection provided that would have the elements copied into
+     * @throws UnsupportedOperationException if the collection is immutable and originals contains a string which starts with the specified search string.
+     * @throws IllegalArgumentException if any parameter is is null
+     * @throws IllegalArgumentException if originals contains a null element. <b>Note: the collection may be modified before this is thrown</b>
+     */
+    public static <T extends Collection<String>> T copyPartialMatches(final String token, final Iterable<String> originals, final T collection) throws UnsupportedOperationException, IllegalArgumentException {
+        Validate.notNull(token, "Search token cannot be null");
+        Validate.notNull(collection, "Collection cannot be null");
+        Validate.notNull(originals, "Originals cannot be null");
+
+        for (String string : originals) {
+            if (startsWithIgnoreCase(string, token)) {
+                collection.add(string);
+            }
+        }
+
+        return collection;
+    }
+
+    /**
+     * This method uses a substring to check case-insensitive equality. This means the internal array does not need to be copied like a toLowerCase() call would.
+     *
+     * @param string String to check
+     * @param prefix Prefix of string to compare
+     * @return true if provided string starts with, ignoring case, the prefix provided
+     * @throws NullPointerException if prefix is null
+     * @throws IllegalArgumentException if string is null
+     */
+    public static boolean startsWithIgnoreCase(final String string, final String prefix) throws IllegalArgumentException, NullPointerException {
+        Validate.notNull(string, "Cannot check a null string for a match");
+        if (string.length() < prefix.length()) {
+            return false;
+        }
+        return string.substring(0, prefix.length()).equalsIgnoreCase(prefix);
+    }
+}