[GitHub] sijie commented on a change in pull request #858: Checksum, ChecksumFactory and Benchmark

[GitBox <gi...@apache.org>]

sijie commented on a change in pull request #858: Checksum, ChecksumFactory and Benchmark
URL: https://github.com/apache/bookkeeper/pull/858#discussion_r158353392
 
 

 ##########
 File path: bookkeeper-common/src/main/java/org/apache/bookkeeper/common/checksum/Checksum.java
 ##########
 @@ -0,0 +1,130 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.bookkeeper.common.checksum;
+
+import java.nio.ByteBuffer;
+
+/**
+ * An interface representing a data checksum.
+ *
+ * <p>The existence of this class is for adopting crc32 and crc32c in java8 and java9.
+ */
+public interface Checksum {
+
+    /**
+     * Updates the current checksum with the specified byte.
+     *
+     * @param b the byte to update the checksum with
+     */
+    void update(int b);
+
+    /**
+     * Updates the current checksum with the specified array of bytes.
+     *
+     * @implSpec This default implementation is equal to calling
+     * {@code update(b, 0, b.length)}.
+     *
+     * @param b the array of bytes to update the checksum with
+     *
+     * @throws NullPointerException
+     *         if {@code b} is {@code null}
+     *
+     * @since 9
+     */
+    default void update(byte[] b) {
+        update(b, 0, b.length);
+    }
+
+    /**
+     * Updates the current checksum with the specified array of bytes.
+     *
+     * @param b the byte array to update the checksum with
+     * @param off the start offset of the data
+     * @param len the number of bytes to use for the update
+     */
+    void update(byte[] b, int off, int len);
+
+    /**
+     * Updates the current checksum with the bytes from the specified buffer.
+     *
+     * <p>The checksum is updated with the remaining bytes in the buffer, starting
+     * at the buffer's position. Upon return, the buffer's position will be
+     * updated to its limit; its limit will not have been changed.
+     *
+     * @apiNote For best performance with DirectByteBuffer and other ByteBuffer
+     * implementations without a backing array implementers of this interface
+     * should override this method.
+     *
+     * @implSpec The default implementation has the following behavior.<br>
+     * For ByteBuffers backed by an accessible byte array.
+     * <pre>{@code
+     * update(buffer.array(),
+     *        buffer.position() + buffer.arrayOffset(),
+     *        buffer.remaining());
+     * }</pre>
+     * For ByteBuffers not backed by an accessible byte array.
+     * <pre>{@code
+     * byte[] b = new byte[Math.min(buffer.remaining(), 4096)];
+     * while (buffer.hasRemaining()) {
+     *     int length = Math.min(buffer.remaining(), b.length);
+     *     buffer.get(b, 0, length);
+     *     update(b, 0, length);
+     * }
+     * }</pre>
+     *
+     * @param buffer the ByteBuffer to update the checksum with
+     *
+     * @throws NullPointerException
+     *         if {@code buffer} is {@code null}
+     *
+     * @since 9
+     */
+    default void update(ByteBuffer buffer) {
 
 Review comment:
   this interface follows java9 checksum interface for bridging java8 and java9. the purpose for this - if we upgrade the minimal support of java version to java9, we can easily drop the stuff we have, and use the java9 interface, we don't need to change logic only imports.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services