| /** |
| * 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.apex.malhar.lib.fs; |
| |
| import java.io.IOException; |
| import org.apache.hadoop.fs.FSDataInputStream; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.lib.io.block.BlockMetadata; |
| import com.datatorrent.lib.io.block.FSSliceReader; |
| import com.datatorrent.lib.io.block.ReaderContext; |
| |
| /** |
| * This operator can be used for reading records/tuples from Filesystem in |
| * parallel (without ordering guarantees between tuples). Records can be |
| * delimited (e.g. newline) or fixed width records. Output tuples are byte[]. |
| * |
| * Typically, this operator will be connected to output of FileSplitterInput to |
| * read records in parallel. |
| * |
| * @since 3.5.0 |
| */ |
| @org.apache.hadoop.classification.InterfaceStability.Evolving |
| public class FSRecordReader extends FSSliceReader |
| { |
| /** |
| * Record reader mode decides how to split the records. |
| */ |
| public static enum RECORD_READER_MODE |
| { |
| DELIMITED_RECORD, FIXED_WIDTH_RECORD; |
| } |
| |
| /** |
| * Criteria for record split |
| */ |
| private RECORD_READER_MODE mode = RECORD_READER_MODE.DELIMITED_RECORD; |
| |
| /** |
| * Length for fixed width record |
| */ |
| private int recordLength; |
| |
| /** |
| * Port to emit individual records/tuples as byte[] |
| */ |
| public final transient DefaultOutputPort<byte[]> records = new DefaultOutputPort<byte[]>(); |
| |
| /** |
| * Initialize appropriate reader context based on mode selection |
| */ |
| @Override |
| public void setup(OperatorContext context) |
| { |
| super.setup(context); |
| if (mode == RECORD_READER_MODE.FIXED_WIDTH_RECORD) { |
| ReaderContext.FixedBytesReaderContext<FSDataInputStream> fixedBytesReaderContext = new ReaderContext.FixedBytesReaderContext<FSDataInputStream>(); |
| fixedBytesReaderContext.setLength(recordLength); |
| readerContext = fixedBytesReaderContext; |
| } else { |
| readerContext = new ReaderContext.ReadAheadLineReaderContext<FSDataInputStream>(); |
| } |
| } |
| |
| /** |
| * Read the block data and emit records based on reader context |
| * |
| * @param blockMetadata |
| * block |
| * @throws IOException |
| */ |
| protected void readBlock(BlockMetadata blockMetadata) throws IOException |
| { |
| readerContext.initialize(stream, blockMetadata, consecutiveBlock); |
| ReaderContext.Entity entity; |
| while ((entity = readerContext.next()) != null) { |
| |
| counters.getCounter(ReaderCounterKeys.BYTES).add(entity.getUsedBytes()); |
| |
| byte[] record = entity.getRecord(); |
| |
| if (record != null) { |
| counters.getCounter(ReaderCounterKeys.RECORDS).increment(); |
| records.emit(record); |
| } |
| } |
| } |
| |
| /** |
| * Criteria for record split |
| * |
| * @param mode |
| * Mode |
| */ |
| public void setMode(RECORD_READER_MODE mode) |
| { |
| this.mode = mode; |
| } |
| |
| /** |
| * Criteria for record split |
| * |
| * @return mode |
| */ |
| public RECORD_READER_MODE getMode() |
| { |
| return mode; |
| } |
| |
| /** |
| * Length for fixed width record |
| * |
| * @param recordLength |
| */ |
| public void setRecordLength(int recordLength) |
| { |
| if (mode == RECORD_READER_MODE.FIXED_WIDTH_RECORD && recordLength <= 0) { |
| throw new IllegalArgumentException("recordLength should be greater than 0."); |
| } |
| this.recordLength = recordLength; |
| } |
| |
| /** |
| * Length for fixed width record |
| * |
| * @return record length |
| */ |
| public int getRecordLength() |
| { |
| return recordLength; |
| } |
| |
| } |