Renamed Md5HashUtils to DigestUtils

Author: poutsma

org.springframework.core/src/main/java/org/springframework/util/DigestUtils.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2002-2009 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.util;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+/**
+ * Miscellaneous method for calculating digests.
+
+ * <p>Mainly for internal use within the framework; consider
+ * <a href="http://jakarta.apache.org/commons/codec/">Jakarta's Commons Codec</a>
+ * for a more comprehensive suite of Digest utilities.
+ *
+ * @author Arjen Poutsma
+ * @since 3.0
+ * @see org.apache.commons.codec.digest.DigestUtils
+ */
+public abstract class DigestUtils {
+
+	private static final String MD5_ALGORITHM_NAME = "MD5";
+
+	private static final char[] HEX_CHARS =
+			{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+
+	/**
+	 * Calculate the MD5 digest of the given bytes.
+	 * @param bytes the bytes to calculate the digest over
+	 * @return the digest
+	 */
+	public static byte[] md5Digest(byte[] bytes) {
+		return digest(MD5_ALGORITHM_NAME, bytes);
+	}
+
+	/**
+	 * Return a hexadecimal string representation of the MD5 digest of the given bytes.
+	 * @param bytes the bytes to calculate the digest over
+	 * @return a hexadecimal digest string
+	 */
+	public static String md5DigestAsHex(byte[] bytes) {
+		return digestAsHexString(MD5_ALGORITHM_NAME, bytes);
+	}
+
+	/**
+	 * Append a hexadecima string representation of the MD5 digest of the given bytes to the given {@link StringBuilder}.
+	 * @param bytes the bytes to calculate the digest over
+	 * @param builder the string builder to append the digest to
+	 * @return the given string builder
+	 */
+	public static StringBuilder appendMd5DigestAsHex(byte[] bytes, StringBuilder builder) {
+		return appendDigestAsHex(MD5_ALGORITHM_NAME, bytes, builder);
+	}
+
+	/**
+	 * Creates a new {@link MessageDigest} with the given algorithm. Necessary because {@code MessageDigest} is not
+	 * thread-safe.
+	 */
+	private static MessageDigest getDigest(String algorithm) {
+		try {
+			return MessageDigest.getInstance(algorithm);
+		}
+		catch (NoSuchAlgorithmException ex) {
+			throw new IllegalStateException("Could not find MessageDigest with algorithm \"" + algorithm + "\"", ex);
+		}
+	}
+
+	private static byte[] digest(String algorithm, byte[] bytes) {
+		return getDigest(algorithm).digest(bytes);
+	}
+
+	private static String digestAsHexString(String algorithm, byte[] bytes) {
+		char[] hexDigest = digestAsHexChars(algorithm, bytes);
+		return new String(hexDigest);
+	}
+
+	private static StringBuilder appendDigestAsHex(String algorithm, byte[] bytes, StringBuilder builder) {
+		char[] hexDigest = digestAsHexChars(algorithm, bytes);
+		return builder.append(hexDigest);
+	}
+
+	private static char[] digestAsHexChars(String algorithm, byte[] bytes) {
+		byte[] digest = digest(algorithm, bytes);
+		return encodeHex(digest);
+	}
+
+	private static char[] encodeHex(byte[] bytes) {
+		char chars[] = new char[32];
+		for (int i = 0; i < chars.length; i = i + 2) {
+			byte b = bytes[i / 2];
+			chars[i] = HEX_CHARS[(b >>> 0x4) & 0xf];
+			chars[i + 1] = HEX_CHARS[b & 0xf];
+		}
+		return chars;
+	}
+
+
+}

org.springframework.core/src/main/java/org/springframework/util/Md5HashUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright ${YEAR} the original author or authors.
+ * Copyright 2002-2009 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,12 +18,11 @@
 
 import java.io.UnsupportedEncodingException;
 
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 import org.junit.Before;
 import org.junit.Test;
 
-public class Md5HashUtilsTests {
+public class DigestUtilsTests {
 
 	private byte[] bytes;
 
@@ -33,23 +32,23 @@ public void createBytes() throws UnsupportedEncodingException {
 	}
 
 	@Test
-	public void hash() {
-		byte[] result = Md5HashUtils.getHash(bytes);
+	public void md5() {
+		byte[] result = DigestUtils.md5Digest(bytes);
 		byte[] expected = new byte[]{-0x4f, 0xa, -0x73, -0x4f, 0x64, -0x20, 0x75, 0x41, 0x5, -0x49, -0x57, -0x65, -0x19,
 				0x2e, 0x3f, -0x1b};
 		assertArrayEquals("Invalid hash", expected, result);
 	}
 
 	@Test
-	public void hashString() throws UnsupportedEncodingException {
-		String hash = Md5HashUtils.getHashString(bytes);
+	public void md5Hex() throws UnsupportedEncodingException {
+		String hash = DigestUtils.md5DigestAsHex(bytes);
 		assertEquals("Invalid hash", "b10a8db164e0754105b7a99be72e3fe5", hash);
 	}
 
 	@Test
-	public void hashStringBuilder() throws UnsupportedEncodingException {
+	public void md5StringBuilder() throws UnsupportedEncodingException {
 		StringBuilder builder = new StringBuilder();
-		Md5HashUtils.appendHashString(bytes, builder);
+		DigestUtils.appendMd5DigestAsHex(bytes, builder);
 		assertEquals("Invalid hash", "b10a8db164e0754105b7a99be72e3fe5", builder.toString());
 	}
 

org.springframework.core/src/test/java/org/springframework/util/Md5HashUtilsTests.java renamed to org.springframework.core/src/test/java/org/springframework/util/DigestUtilsTests.java

@@ -28,8 +28,8 @@
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpServletResponseWrapper;
 
+import org.springframework.util.DigestUtils;
 import org.springframework.util.FileCopyUtils;
-import org.springframework.util.Md5HashUtils;
 import org.springframework.web.util.WebUtils;
 
 /**
@@ -83,11 +83,11 @@ protected void doFilterInternal(HttpServletRequest request, HttpServletResponse
 	 *
 	 * @param bytes the response bdoy as byte array
 	 * @return the ETag header value
-	 * @see Md5HashUtils
+	 * @see org.springframework.util.DigestUtils
 	 */
 	protected String generateETagHeaderValue(byte[] bytes) {
 		StringBuilder builder = new StringBuilder("\"0");
-		Md5HashUtils.appendHashString(bytes, builder);
+		DigestUtils.appendMd5DigestAsHex(bytes, builder);
 		builder.append('"');
 		return builder.toString();
 	}