Revert "Parse protocol"

This reverts commit 906a4d7.

Author: TaiJuWu

clients/src/main/java/org/apache/kafka/common/utils/Utils.java

@@ -94,14 +94,12 @@ public final class Utils {
 
     private Utils() {}
 
-    // This matches URIs of formats: host:port
+    // This matches URIs of formats: host:port and protocol://host:port
     // IPv6 is supported with [ip] pattern
     private static final Pattern HOST_PORT_PATTERN = Pattern.compile("^(?:[0-9a-zA-Z\\-%._]*://)?\\[?([0-9a-zA-Z\\-%._:]*)]?:([0-9]+)");
 
     private static final Pattern VALID_HOST_CHARACTERS = Pattern.compile("([0-9a-zA-Z\\-%._:]*)");
 
-    private static final Pattern PROTOCOL_PATTERN = Pattern.compile("([A-Za-z0-9_]+)://");
-
     // Prints up to 2 decimal digits. Used for human-readable printing
     private static final DecimalFormat TWO_DIGIT_FORMAT = new DecimalFormat("0.##",
         DecimalFormatSymbols.getInstance(Locale.ENGLISH));
@@ -531,16 +529,6 @@ public static int murmur2(final byte[] data) {
         return h;
     }
 
-    /**
-     * Extracts the protocol from a "protocol://host:port" address string.
-     * @param address address string to parse
-     * @return hostname or null if the given address is incorrect
-     */
-    public static String getProtocol(String address) {
-        Matcher matcher = PROTOCOL_PATTERN.matcher(address);
-        return matcher.lookingAt() ? matcher.group(1) : null;
-    }
-
     /**
      * Extracts the hostname from a "host:port" address string.
      * @param address address string to parse

clients/src/test/java/org/apache/kafka/common/utils/UtilsTest.java

@@ -132,18 +132,6 @@ public void testGetHostValid(String protocol) {
         assertEquals("::1", getHost("[::1]:1234"));
     }
 
-    @ParameterizedTest
-    @CsvSource(value = {"PLAINTEXT", "SASL_PLAINTEXT", "SSL", "SASL_SSL"})
-    public void testGetProtocol(String protocol) {
-        assertEquals(protocol, getProtocol(protocol + "://mydomain.com:8080"));
-        assertEquals(protocol, getProtocol(protocol + "://MyDomain.com:8080"));
-        assertEquals(protocol, getProtocol(protocol + "://My_Domain.com:8080"));
-        assertEquals(protocol, getProtocol(protocol + "://[::1]:1234"));
-        assertEquals(protocol, getProtocol(protocol + "://[2001:db8:85a3:8d3:1319:8a2e:370:7348]:5678"));
-        assertEquals(protocol, getProtocol(protocol + "://[2001:DB8:85A3:8D3:1319:8A2E:370:7348]:5678"));
-        assertEquals(protocol, getProtocol(protocol + "://[fe80::b1da:69ca:57f7:63d8%3]:5678"));
-    }
-
     @ParameterizedTest
     @CsvSource(value = {"PLAINTEXT", "SASL_PLAINTEXT", "SSL", "SASL_SSL"})
     public void testGetHostInvalid(String protocol) {