steveloughran commented on code in PR #968: URL: https://github.com/apache/parquet-mr/pull/968#discussion_r893760667
########## parquet-common/src/main/java/org/apache/parquet/bytes/SequenceByteBufferInputStream.java: ########## @@ -0,0 +1,269 @@ +/* + * 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.parquet.bytes; + +import java.io.EOFException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.Iterator; +import java.util.List; + +/** + * A bare minimum implementation of a {@link java.io.SequenceInputStream} that wraps an + * <i>ordered</i> collection of ByteBufferInputStreams. + * <p> + * This class, as implemented, is intended only for a specific use in the ParquetFileReader and + * throws {@link UnsupportedOperationException} in unimplemented methods to catch any unintended + * use in other cases. + * <p> + * Even thought this class is derived from ByteBufferInputStream it explicitly does not support any + * byte buffer related methods like slice. It does, however support sliceBuffers which is a + * curious case of reading data from underlying streams + * <p> + * Even though this class changes the state of the underlying streams (by reading from them) + * it does not own them and so the close method does not close the streams. To avoid resource + * leaks the calling code should close the underlying streams + */ +public class SequenceByteBufferInputStream extends ByteBufferInputStream { + + Collection<ByteBufferInputStream> collection; + Iterator<ByteBufferInputStream> iterator; + ByteBufferInputStream current; + long position = 0; + + @Override + public String toString() { + return "SequenceByteBufferInputStream{" + + "collection=" + collection + + ", current=" + current + + ", position=" + position + + '}'; + } + + public SequenceByteBufferInputStream(Collection<ByteBufferInputStream> collection) { + this.collection = collection; + iterator = collection.iterator(); + current = iterator.hasNext() ? iterator.next() : null; + if (current == null) { + throw new UnsupportedOperationException( + "Initializing SequenceByteBufferInputStream with an empty collection is not supported"); + } + } + + @Override + public long position() { + return position; + } + + @Override + public int read(ByteBuffer out) { Review Comment: good to know. -- 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: dev-unsubscr...@parquet.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
