nizhikov commented on code in PR #11518: URL: https://github.com/apache/ignite/pull/11518#discussion_r1812516874
########## modules/core/src/main/java/org/apache/ignite/internal/jdbc2/lob/JdbcBlobBuffer.java: ########## @@ -0,0 +1,333 @@ +/* + * 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.ignite.internal.jdbc2.lob; + +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; + +/** + * Buffer storing the binary data. + * + * <p>Buffer can start working in read-only mode if created wrapping the existing byte array which + * can not be modified. Any write operation switches it lazily to the read-write mode. This allows + * to prevent the unnecessary data copying. + * + * <p>Data is read via the InputStream API and modified via the OutputStream one. Changes done via + * OutputStream are visible via the InputStream even if InputStream is created before changes done. + * + * <p>InputStream and OutputStream created remain valid even if the underlying data storage changed from + * read-only to read-write. + * + * <p>Note however that implementation is not thread-safe. + */ +public class JdbcBlobBuffer { + /** The underlying data storage. */ + private JdbcBlobStorage storage; + + /** + * Create buffer which wraps the existing byte array and start working in the read-only mode. + * + * @param arr The byte array to be wrapped. + * @param off The offset to the first byte to be wrapped. + * @param len The length in bytes of the data to be wrapped. + */ + public static JdbcBlobBuffer createReadOnly(byte[] arr, int off, int len) { + return new JdbcBlobBuffer(new JdbcBlobReadOnlyStorage(arr, off, len)); + } + + /** + * Create buffer which takes ownerhip of and wraps the existing byte array and starts working in + * the read-write mode. + * + * @param arr The byte array to be wrapped. + */ + public static JdbcBlobBuffer createReadWrite(byte[] arr) { + return new JdbcBlobBuffer(new JdbcBlobReadWriteStorage(arr)); + } + + /** + * Create empty buffer which starts working in the read-write mode. + */ + public static JdbcBlobBuffer createReadWrite() { + return new JdbcBlobBuffer(new JdbcBlobReadWriteStorage()); + } + + /** + * Create shallow copy of the buffer passed. + * + * <p>Sharing of the underlying storage is intended. + * + * @param other Other buffer. + */ + public static JdbcBlobBuffer shallowCopy(JdbcBlobBuffer other) { + return new JdbcBlobBuffer(other.storage); + } + + /** + * Create buffer which wraps the passed storage instance. + * @param storage Storage instance. + */ + private JdbcBlobBuffer(JdbcBlobStorage storage) { + this.storage = storage; + } + + /** + * @return Total number of bytes in the buffer. + */ + public long totalCnt() { + return storage.totalCnt(); + } + + /** + * Provide OutputStream through which the data can be written to buffer starting from + * the (zero-based) position. + * + * @param pos The zero-based offset to the first byte to be written. Must not be negative + * or greater than total count of bytes in buffer. + * + * @return OutputStream instance. + */ + public OutputStream getOutputStream(long pos) { + return new BufferOutputStream(pos); + } + + /** + * Provide InputStream through which the data can be read starting from the + * begining. + * + * <p>Stream is not limited meaning that it would return any new data + * written to the buffer after stream creation. + * + * @return InputStream instance. + */ + public InputStream getInputStream() { + return new BufferInputStream(); + } + + /** + * Provide InputStream through which the no more than {@code len} bytes can be read + * from buffer starting from the specified zero-based position {@code pos}. + * + * @param pos The zero-based offset to the first byte to be retrieved. Must not be negative + * or greater than total count of bytes in buffer. + * @param len The length in bytes of the data to be retrieved. Must not be negative. + * @return InputStream instance. + */ + public InputStream getInputStream(long pos, long len) { + return new BufferInputStream(pos, len); + } + + /** + * Truncate the buffer to the specified length. + * + * @param len The length in bytes to be truncated. Must not be negative + * or greater than total count of bytes in buffer. + */ + public void truncate(long len) throws IOException { + try { + storage.truncate(len); Review Comment: Logic based on exceptions must be omited. Let's rework this as following: ``` if (storage.readOnly()) switchToReadWriteMemoryStorage(); storage.truncate(len); ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@ignite.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
