amousavigourabi commented on code in PR #1230: URL: https://github.com/apache/parquet-mr/pull/1230#discussion_r1425903622
########## parquet-common/src/main/java/org/apache/parquet/compression/FallbackCodecFactory.java: ########## @@ -0,0 +1,74 @@ +/* + * 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.compression; + +import org.apache.parquet.Preconditions; +import org.apache.parquet.hadoop.metadata.CompressionCodecName; + +/** + * {@link CompressionCodecFactory} implementation that delegates to the {@link CompressionCodecFactory} implementations it was constructed with. + */ +public class FallbackCodecFactory implements CompressionCodecFactory { + + private final CompressionCodecFactory[] codecFactories; + + /** + * Constructs a FallbackCodecFactory using other {@link CompressionCodecFactory} implementations. + * The FallbackCodecFactory recognizes that a codec could not be provided by the {@link CompressionCodecFactory} implementations throwing a {@link CodecNotImplementedException}. + * + * @param codecFactories the {@link CompressionCodecFactory} implementations to delegate to, in order. + */ + public FallbackCodecFactory(CompressionCodecFactory... codecFactories) { + Preconditions.checkArgument( + codecFactories != null && codecFactories.length > 0, + "FallbackCodecFactory needs to be constructed using at least one CompressionCodecFactory to fall back on."); + this.codecFactories = codecFactories; + } + + @Override + public BytesInputCompressor getCompressor(CompressionCodecName codecName) { + for (CompressionCodecFactory codecFactory : codecFactories) { + try { + return codecFactory.getCompressor(codecName); Review Comment: I'm not sure whether that would be a good idea, using the custom exception here seems more idiomatic. Using null returns in codec factories would probably also run into relatively hard-to-diagnose issues when used without such fallback mechanisms, so I'd prefer to discourage null returns as much as possible when (de)compressors cannot be resolved for these specialized user implementations. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
