/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.nephele.util;
import java.util.Iterator;
import eu.stratosphere.core.fs.FSDataInputStream;
import eu.stratosphere.core.fs.FileInputSplit;
import eu.stratosphere.core.fs.FileSystem;
import eu.stratosphere.core.io.StringRecord;
import eu.stratosphere.runtime.io.api.RecordWriter;
import eu.stratosphere.nephele.template.AbstractFileInputTask;
import eu.stratosphere.runtime.fs.LineReader;
/**
* A file line reader reads the associated file input splits line by line and outputs the lines as string records.
*
*/
public class FileLineReader extends AbstractFileInputTask {
private RecordWriter<StringRecord> output = null;
@Override
public void invoke() throws Exception {
output.initializeSerializers();
final Iterator<FileInputSplit> splitIterator = getFileInputSplits();
while (splitIterator.hasNext()) {
final FileInputSplit split = splitIterator.next();
long start = split.getStart();
long length = split.getLength();
final FileSystem fs = FileSystem.get(split.getPath().toUri());
final FSDataInputStream fdis = fs.open(split.getPath());
final LineReader lineReader = new LineReader(fdis, start, length, (1024 * 1024));
byte[] line = lineReader.readLine();
while (line != null) {
// Create a string object from the data read
StringRecord str = new StringRecord();
str.set(line);
// Send out string
output.emit(str);
line = lineReader.readLine();
}
// Close the stream;
lineReader.close();
}
this.output.flush();
}
@Override
public void registerInputOutput() {
output = new RecordWriter<StringRecord>(this);
}
}