src/java.base/share/classes/java/net/URLDecoder.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -24,10 +24,14 @@
  */
 
 package java.net;
 
 import java.io.*;
+import java.nio.charset.Charset;
+import java.nio.charset.IllegalCharsetNameException;
+import java.nio.charset.UnsupportedCharsetException;
+import java.util.Objects;
 
 /**
  * Utility class for HTML form decoding. This class contains static methods
  * for decoding a String from the <CODE>application/x-www-form-urlencoded</CODE>
  * MIME format.

@@ -106,43 +110,75 @@
     }
 
     /**
      * Decodes an {@code application/x-www-form-urlencoded} string using
      * a specific encoding scheme.
-     * The supplied encoding is used to determine
-     * what characters are represented by any consecutive sequences of the
-     * form "<i>{@code %xy}</i>".
+     *
      * <p>
-     * <em><strong>Note:</strong> The <a href=
-     * "http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars">
-     * World Wide Web Consortium Recommendation</a> states that
-     * UTF-8 should be used. Not doing so may introduce
-     * incompatibilities.</em>
+     * This method behaves the same as {@linkplain decode(String s, Charset charset)}
+     * except that it will {@linkplain java.nio.charset.Charset#forName look up the charset}
+     * using the given encoding name.
+     *
+     * @implNote This implementation will throw an {@link java.lang.IllegalArgumentException}
+     * when illegal strings are encountered.
      *
      * @param s the {@code String} to decode
      * @param enc   The name of a supported
      *    <a href="../lang/package-summary.html#charenc">character
      *    encoding</a>.
      * @return the newly decoded {@code String}
-     * @exception  UnsupportedEncodingException
+     * @throws UnsupportedEncodingException
      *             If character encoding needs to be consulted, but
      *             named character encoding is not supported
      * @see URLEncoder#encode(java.lang.String, java.lang.String)
      * @since 1.4
      */
-    public static String decode(String s, String enc)
-        throws UnsupportedEncodingException{
+    public static String decode(String s, String enc) throws UnsupportedEncodingException {
+        if (enc.length() == 0) {
+            throw new UnsupportedEncodingException ("URLDecoder: empty string enc parameter");
+        }
 
+        try {
+            Charset charset = Charset.forName(enc);
+            return decode(s, charset);
+        } catch (IllegalCharsetNameException | UnsupportedCharsetException e) {
+            throw new UnsupportedEncodingException(enc);
+        }
+    }
+
+    /**
+     * Decodes an {@code application/x-www-form-urlencoded} string using
+     * a specific {@linkplain java.nio.charset.Charset Charset}.
+     * The supplied charset is used to determine
+     * what characters are represented by any consecutive sequences of the
+     * form "<i>{@code %xy}</i>".
+     * <p>
+     * <em><strong>Note:</strong> The <a href=
+     * "http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars">
+     * World Wide Web Consortium Recommendation</a> states that
+     * UTF-8 should be used. Not doing so may introduce
+     * incompatibilities.</em>
+     *
+     * @implNote This implementation will throw an {@link java.lang.IllegalArgumentException}
+     * when illegal strings are encountered.
+     *
+     * @param s the {@code String} to decode
+     * @param charset the given charset
+     * @return the newly decoded {@code String}
+     * @throws NullPointerException if {@code s} or {@code charset} is {@code null}
+     * @throws IllegalArgumentException if the implementation encounters illegal
+     * characters
+     * @see URLEncoder#encode(java.lang.String, java.nio.charset.Charset)
+     * @since 10
+     */
+    public static String decode(String s, Charset charset) {
+        Objects.requireNonNull(charset, "Charset");
         boolean needToChange = false;
         int numChars = s.length();
         StringBuilder sb = new StringBuilder(numChars > 500 ? numChars / 2 : numChars);
         int i = 0;
 
-        if (enc.length() == 0) {
-            throw new UnsupportedEncodingException ("URLDecoder: empty string enc parameter");
-        }
-
         char c;
         byte[] bytes = null;
         while (i < numChars) {
             c = s.charAt(i);
             switch (c) {

@@ -171,11 +207,13 @@
 
                     while ( ((i+2) < numChars) &&
                             (c=='%')) {
                         int v = Integer.parseInt(s, i + 1, i + 3, 16);
                         if (v < 0)
-                            throw new IllegalArgumentException("URLDecoder: Illegal hex characters in escape (%) pattern - negative value");
+                            throw new IllegalArgumentException(
+                                    "URLDecoder: Illegal hex characters in escape "
+                                            + "(%) pattern - negative value");
                         bytes[pos++] = (byte) v;
                         i+= 3;
                         if (i < numChars)
                             c = s.charAt(i);
                     }

@@ -185,11 +223,11 @@
 
                     if ((i < numChars) && (c=='%'))
                         throw new IllegalArgumentException(
                          "URLDecoder: Incomplete trailing escape (%) pattern");
 
-                    sb.append(new String(bytes, 0, pos, enc));
+                    sb.append(new String(bytes, 0, pos, charset));
                 } catch (NumberFormatException e) {
                     throw new IllegalArgumentException(
                     "URLDecoder: Illegal hex characters in escape (%) pattern - "
                     + e.getMessage());
                 }