wayang-platforms/wayang-flink/src/main/java/org/apache/wayang/flink/compiler/WayangFileOutputFormat.java - incubator-wayang - Git at Google

 /*
  * 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.wayang.flink.compiler;

 import org.apache.flink.api.common.io.BlockInfo;
 import org.apache.flink.api.common.io.CleanupWhenUnsuccessful;
 import org.apache.flink.api.common.io.FileOutputFormat;
 import org.apache.flink.api.common.io.InitializeOnMaster;
 import org.apache.flink.configuration.Configuration;
 import org.apache.flink.configuration.GlobalConfiguration;
 import org.apache.flink.core.fs.FSDataOutputStream;
 import org.apache.flink.core.fs.FileSystem;
 import org.apache.flink.core.fs.Path;
 import org.apache.flink.core.memory.DataOutputView;
 import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
 import org.apache.hadoop.io.BytesWritable;
 import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.SequenceFile;
 import org.apache.wayang.core.api.exception.WayangException;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;

 import java.io.ByteArrayOutputStream;
 import java.io.FileNotFoundException;
 import java.io.FilterOutputStream;
 import java.io.IOException;
 import java.io.ObjectOutputStream;
 import java.io.OutputStream;
 import java.net.URI;

 /**
  * Wrapper for {@link FileOutputFormat}
  */
 public class WayangFileOutputFormat<IT> extends FileOutputFormat<IT> implements InitializeOnMaster, CleanupWhenUnsuccessful {

     private static final long serialVersionUID = 1L;

     // --------------------------------------------------------------------------------------------

     private static FileSystem.WriteMode DEFAULT_WRITE_MODE;

     private static FileOutputFormat.OutputDirectoryMode DEFAULT_OUTPUT_DIRECTORY_MODE;

     static {
         initDefaultsFromConfiguration(GlobalConfiguration.loadConfiguration());
     }

     /**
      * Initialize defaults for output format. Needs to be a static method because it is configured for local
      * cluster execution, see LocalFlinkMiniCluster.
      * @param configuration The configuration to load defaults from
      */
     public static void initDefaultsFromConfiguration(Configuration configuration) {

         DEFAULT_WRITE_MODE = FileSystem.WriteMode.OVERWRITE ;


         DEFAULT_OUTPUT_DIRECTORY_MODE =  FileOutputFormat.OutputDirectoryMode.PARONLY;
     }

     // --------------------------------------------------------------------------------------------

     /**
      * The LOG for logging messages in this class.
      */
     private static final Logger LOG = LogManager.getLogger(FileOutputFormat.class);

     /**
      * The key under which the name of the target path is stored in the configuration.
      */
     public static final String FILE_PARAMETER_KEY = "flink.output.file";

     /**
      * The path of the file to be written.
      */
     protected Path outputFilePath;

     /**
      * The write mode of the output.
      */
     private FileSystem.WriteMode writeMode;

     /**
      * The output directory mode
      */
     private FileOutputFormat.OutputDirectoryMode outputDirectoryMode;

     SequenceFile.Writer writer;
     // --------------------------------------------------------------------------------------------

     /** The stream to which the data is written; */
     protected transient FSDataOutputStream stream;

     /** The path that is actually written to (may a a file in a the directory defined by {@code outputFilePath} ) */
     private transient Path actualFilePath;

     /** Flag indicating whether this format actually created a file, which should be removed on cleanup. */
     private transient boolean fileCreated;

     /** The config parameter which defines the fixed length of a record. */
     public static final String BLOCK_SIZE_PARAMETER_KEY = "output.block_size";

     public static final long NATIVE_BLOCK_SIZE = Long.MIN_VALUE;

     /** The block size to use. */
     private long blockSize = NATIVE_BLOCK_SIZE;

     private transient WayangFileOutputFormat.BlockBasedOutput blockBasedOutput;

     private transient DataOutputViewStreamWrapper outView;

     // --------------------------------------------------------------------------------------------

     public WayangFileOutputFormat() {}

     public WayangFileOutputFormat(String path){
         this( new Path(URI.create(path)) );
     }

     public WayangFileOutputFormat(Path outputPath) {
         this.outputFilePath = outputPath;
     }

     public void setOutputFilePath(Path path) {
         if (path == null) {
             throw new IllegalArgumentException("Output file path may not be null.");
         }

         this.outputFilePath = path;
     }

     public Path getOutputFilePath() {
         return this.outputFilePath;
     }


     public void setWriteMode(FileSystem.WriteMode mode) {
         if (mode == null) {
             throw new NullPointerException();
         }
         this.writeMode = mode;
     }

     public FileSystem.WriteMode getWriteMode() {
         return this.writeMode;
     }


     public void setOutputDirectoryMode(FileOutputFormat.OutputDirectoryMode mode) {
         if (mode == null) {
             throw new NullPointerException();
         }

         this.outputDirectoryMode = mode;
     }

     public FileOutputFormat.OutputDirectoryMode getOutputDirectoryMode() {
         return this.outputDirectoryMode;
     }


     // ----------------------------------------------------------------

     @Override
     public void configure(Configuration parameters) {
         try {
             // get the output file path, if it was not yet set
             if (this.outputFilePath == null) {
                 // get the file parameter
                 String filePath = parameters.getString(FILE_PARAMETER_KEY, null);
                 if (filePath == null) {
                     throw new IllegalArgumentException("The output path has been specified neither via constructor/setters" +
                             ", nor via the Configuration.");
                 }

                 try {
                     this.outputFilePath = new Path(filePath);
                 } catch (RuntimeException rex) {
                     throw new RuntimeException("Could not create a valid URI from the given file path name: " + rex.getMessage());
                 }
             }

             // check if have not been set and use the defaults in that case
             if (this.writeMode == null) {
                 this.writeMode = DEFAULT_WRITE_MODE;
             }

             if (this.outputDirectoryMode == null) {
                 this.outputDirectoryMode = DEFAULT_OUTPUT_DIRECTORY_MODE;
             }


             // read own parameters
             this.blockSize = parameters.getLong(BLOCK_SIZE_PARAMETER_KEY, NATIVE_BLOCK_SIZE);
             if (this.blockSize < 1 && this.blockSize != NATIVE_BLOCK_SIZE) {
                 throw new IllegalArgumentException("The block size parameter must be set and larger than 0.");
             }
             if (this.blockSize > Integer.MAX_VALUE) {
                 throw new UnsupportedOperationException("Currently only block size up to Integer.MAX_VALUE are supported");
             }
         } catch (Exception e){
             throw new WayangException(e);
         }
     }


     @Override
     public void open(int taskNumber, int numTasks) throws IOException {
         try {
             if (taskNumber < 0 || numTasks < 1) {
                 throw new IllegalArgumentException("TaskNumber: " + taskNumber + ", numTasks: " + numTasks);
             }

             if (LOG.isDebugEnabled()) {
                 LOG.debug("Opening stream for output (" + (taskNumber + 1) + "/" + numTasks + "). WriteMode=" + writeMode +
                         ", OutputDirectoryMode=" + outputDirectoryMode);
             }

             Path p = this.outputFilePath;
             if (p == null) {
                 throw new IOException("The file path is null.");
             }

             final FileSystem fs = p.getFileSystem();

             if(fs.exists(p)) {
                 fs.delete(p, true);
             }

             this.fileCreated = true;


             final SequenceFile.Writer.Option fileOption = SequenceFile.Writer.file(new org.apache.hadoop.fs.Path(p.toString()));
             final SequenceFile.Writer.Option keyClassOption = SequenceFile.Writer.keyClass(NullWritable.class);
             final SequenceFile.Writer.Option valueClassOption = SequenceFile.Writer.valueClass(BytesWritable.class);
             writer = SequenceFile.createWriter(new org.apache.hadoop.conf.Configuration(true), fileOption, keyClassOption, valueClassOption);
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     @Override
     public void writeRecord(IT record) throws IOException {
         //this.blockBasedOutput.startRecord();
         try{
             ByteArrayOutputStream b = new ByteArrayOutputStream();
             ObjectOutputStream objStream = new ObjectOutputStream(b);
             objStream.writeObject(record);
             BytesWritable bytesWritable = new BytesWritable(b.toByteArray());
             writer.append(NullWritable.get(), bytesWritable);
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     protected String getDirectoryFileName(int taskNumber) {
         return Integer.toString(taskNumber + 1);
     }

     @Override
     public void close() throws IOException {
         try {
             this.writer.close();
             DataOutputViewStreamWrapper o = this.outView;
             if (o != null) {
                 o.close();
             }
         }
         finally {
             final FSDataOutputStream s = this.stream;
             if (s != null) {
                 this.stream = null;
                 s.close();
             }
         }
     }

     /**
      * Initialization of the distributed file system if it is used.
      *
      * @param parallelism The task parallelism.
      */
     @Override
     public void initializeGlobal(int parallelism) throws IOException {
         try {
             final Path path = getOutputFilePath();
             final FileSystem fs = path.getFileSystem();

             // only distributed file systems can be initialized at start-up time.
             if (fs.isDistributedFS()) {

                 final FileSystem.WriteMode writeMode = getWriteMode();
                 final FileOutputFormat.OutputDirectoryMode outDirMode = getOutputDirectoryMode();

                 if (parallelism == 1 && outDirMode == FileOutputFormat.OutputDirectoryMode.PARONLY) {
                     // output is not written in parallel and should be written to a single file.
                     // prepare distributed output path
                     if (!fs.initOutPathDistFS(path, writeMode, false)) {
                         // output preparation failed! Cancel task.
                         throw new IOException("Output path could not be initialized.");
                     }

                 } else {
                     // output should be written to a directory

                     // only distributed file systems can be initialized at start-up time.
                     if (!fs.initOutPathDistFS(path, writeMode, true)) {
                         throw new IOException("Output directory could not be created.");
                     }
                 }
             }
         }catch (Exception e){
             throw new WayangException(e);
         }
     }

     @Override
     public void tryCleanupOnError() {
         if (this.fileCreated) {
             this.fileCreated = false;

             try {
                 close();
             } catch (IOException e) {
                 LOG.error("Could not properly close FileOutputFormat.", e);
             }

             try {
                 FileSystem.get(this.actualFilePath.toUri()).delete(actualFilePath, false);
             } catch (FileNotFoundException e) {
                 // ignore, may not be visible yet or may be already removed
             } catch (Throwable t) {
                 LOG.error("Could not remove the incomplete file " + actualFilePath + '.', t);
             }
         }
     }

     /**
      * Writes a block info at the end of the blocks.<br>
      * Current implementation uses only int and not long.
      *
      */
     protected class BlockBasedOutput extends FilterOutputStream {

         private static final int NO_RECORD = -1;

         private final int maxPayloadSize;

         private int blockPos;

         private int blockCount, totalCount;

         private long firstRecordStartPos = NO_RECORD;

         private BlockInfo blockInfo = WayangFileOutputFormat.this.createBlockInfo();

         private DataOutputView headerStream;

         public BlockBasedOutput(OutputStream out, int blockSize) {
             super(out);
             this.headerStream = new DataOutputViewStreamWrapper(out);
             this.maxPayloadSize = blockSize - this.blockInfo.getInfoSize();
         }

         @Override
         public void close() throws IOException {
             if (this.blockPos > 0) {
                 this.writeInfo();
             }
             super.flush();
             super.close();
         }

         public void startRecord() {
             if (this.firstRecordStartPos == NO_RECORD) {
                 this.firstRecordStartPos = this.blockPos;
             }
             this.blockCount++;
             this.totalCount++;
         }

         @Override
         public void write(byte[] b) throws IOException {
             this.write(b, 0, b.length);
         }

         @Override
         public void write(byte[] b, int off, int len) throws IOException {

             for (int remainingLength = len, offset = off; remainingLength > 0;) {
                 int blockLen = Math.min(remainingLength, this.maxPayloadSize - this.blockPos);
                 this.out.write(b, offset, blockLen);

                 this.blockPos += blockLen;
                 if (this.blockPos >= this.maxPayloadSize) {
                     this.writeInfo();
                 }
                 remainingLength -= blockLen;
                 offset += blockLen;
             }
         }

         @Override
         public void write(int b) throws IOException {
             super.write(b);
             if (++this.blockPos >= this.maxPayloadSize) {
                 this.writeInfo();
             }
         }

         private void writeInfo() throws IOException {
             this.blockInfo.setRecordCount(this.blockCount);
             this.blockInfo.setAccumulatedRecordCount(this.totalCount);
             this.blockInfo.setFirstRecordStart(this.firstRecordStartPos == NO_RECORD ? 0 : this.firstRecordStartPos);
             WayangFileOutputFormat.this.complementBlockInfo(this.blockInfo);
             this.blockInfo.write(this.headerStream);
             this.blockPos = 0;
             this.blockCount = 0;
             this.firstRecordStartPos = NO_RECORD;
         }
     }
     protected BlockInfo createBlockInfo() {
         return new BlockInfo();
     }
     protected void complementBlockInfo(BlockInfo blockInfo) {}
 }
	/*
	* 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.wayang.flink.compiler;

	import org.apache.flink.api.common.io.BlockInfo;
	import org.apache.flink.api.common.io.CleanupWhenUnsuccessful;
	import org.apache.flink.api.common.io.FileOutputFormat;
	import org.apache.flink.api.common.io.InitializeOnMaster;
	import org.apache.flink.configuration.Configuration;
	import org.apache.flink.configuration.GlobalConfiguration;
	import org.apache.flink.core.fs.FSDataOutputStream;
	import org.apache.flink.core.fs.FileSystem;
	import org.apache.flink.core.fs.Path;
	import org.apache.flink.core.memory.DataOutputView;
	import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
	import org.apache.hadoop.io.BytesWritable;
	import org.apache.hadoop.io.NullWritable;
	import org.apache.hadoop.io.SequenceFile;
	import org.apache.wayang.core.api.exception.WayangException;
	import org.apache.logging.log4j.LogManager;
	import org.apache.logging.log4j.Logger;

	import java.io.ByteArrayOutputStream;
	import java.io.FileNotFoundException;
	import java.io.FilterOutputStream;
	import java.io.IOException;
	import java.io.ObjectOutputStream;
	import java.io.OutputStream;
	import java.net.URI;

	/**
	* Wrapper for {@link FileOutputFormat}
	*/
	public class WayangFileOutputFormat<IT> extends FileOutputFormat<IT> implements InitializeOnMaster, CleanupWhenUnsuccessful {

	private static final long serialVersionUID = 1L;

	// --------------------------------------------------------------------------------------------

	private static FileSystem.WriteMode DEFAULT_WRITE_MODE;

	private static FileOutputFormat.OutputDirectoryMode DEFAULT_OUTPUT_DIRECTORY_MODE;

	static {
	initDefaultsFromConfiguration(GlobalConfiguration.loadConfiguration());
	}

	/**
	* Initialize defaults for output format. Needs to be a static method because it is configured for local
	* cluster execution, see LocalFlinkMiniCluster.
	* @param configuration The configuration to load defaults from
	*/
	public static void initDefaultsFromConfiguration(Configuration configuration) {

	DEFAULT_WRITE_MODE = FileSystem.WriteMode.OVERWRITE ;


	DEFAULT_OUTPUT_DIRECTORY_MODE = FileOutputFormat.OutputDirectoryMode.PARONLY;
	}

	// --------------------------------------------------------------------------------------------

	/**
	* The LOG for logging messages in this class.
	*/
	private static final Logger LOG = LogManager.getLogger(FileOutputFormat.class);

	/**
	* The key under which the name of the target path is stored in the configuration.
	*/
	public static final String FILE_PARAMETER_KEY = "flink.output.file";

	/**
	* The path of the file to be written.
	*/
	protected Path outputFilePath;

	/**
	* The write mode of the output.
	*/
	private FileSystem.WriteMode writeMode;

	/**
	* The output directory mode
	*/
	private FileOutputFormat.OutputDirectoryMode outputDirectoryMode;

	SequenceFile.Writer writer;
	// --------------------------------------------------------------------------------------------

	/** The stream to which the data is written; */
	protected transient FSDataOutputStream stream;

	/** The path that is actually written to (may a a file in a the directory defined by {@code outputFilePath} ) */
	private transient Path actualFilePath;

	/** Flag indicating whether this format actually created a file, which should be removed on cleanup. */
	private transient boolean fileCreated;

	/** The config parameter which defines the fixed length of a record. */
	public static final String BLOCK_SIZE_PARAMETER_KEY = "output.block_size";

	public static final long NATIVE_BLOCK_SIZE = Long.MIN_VALUE;

	/** The block size to use. */
	private long blockSize = NATIVE_BLOCK_SIZE;

	private transient WayangFileOutputFormat.BlockBasedOutput blockBasedOutput;

	private transient DataOutputViewStreamWrapper outView;

	// --------------------------------------------------------------------------------------------

	public WayangFileOutputFormat() {}

	public WayangFileOutputFormat(String path){
	this( new Path(URI.create(path)) );
	}

	public WayangFileOutputFormat(Path outputPath) {
	this.outputFilePath = outputPath;
	}

	public void setOutputFilePath(Path path) {
	if (path == null) {
	throw new IllegalArgumentException("Output file path may not be null.");
	}

	this.outputFilePath = path;
	}

	public Path getOutputFilePath() {
	return this.outputFilePath;
	}


	public void setWriteMode(FileSystem.WriteMode mode) {
	if (mode == null) {
	throw new NullPointerException();
	}
	this.writeMode = mode;
	}

	public FileSystem.WriteMode getWriteMode() {
	return this.writeMode;
	}


	public void setOutputDirectoryMode(FileOutputFormat.OutputDirectoryMode mode) {
	if (mode == null) {
	throw new NullPointerException();
	}

	this.outputDirectoryMode = mode;
	}

	public FileOutputFormat.OutputDirectoryMode getOutputDirectoryMode() {
	return this.outputDirectoryMode;
	}


	// ----------------------------------------------------------------

	@Override
	public void configure(Configuration parameters) {
	try {
	// get the output file path, if it was not yet set
	if (this.outputFilePath == null) {
	// get the file parameter
	String filePath = parameters.getString(FILE_PARAMETER_KEY, null);
	if (filePath == null) {
	throw new IllegalArgumentException("The output path has been specified neither via constructor/setters" +
	", nor via the Configuration.");
	}

	try {
	this.outputFilePath = new Path(filePath);
	} catch (RuntimeException rex) {
	throw new RuntimeException("Could not create a valid URI from the given file path name: " + rex.getMessage());
	}
	}

	// check if have not been set and use the defaults in that case
	if (this.writeMode == null) {
	this.writeMode = DEFAULT_WRITE_MODE;
	}

	if (this.outputDirectoryMode == null) {
	this.outputDirectoryMode = DEFAULT_OUTPUT_DIRECTORY_MODE;
	}


	// read own parameters
	this.blockSize = parameters.getLong(BLOCK_SIZE_PARAMETER_KEY, NATIVE_BLOCK_SIZE);
	if (this.blockSize < 1 && this.blockSize != NATIVE_BLOCK_SIZE) {
	throw new IllegalArgumentException("The block size parameter must be set and larger than 0.");
	}
	if (this.blockSize > Integer.MAX_VALUE) {
	throw new UnsupportedOperationException("Currently only block size up to Integer.MAX_VALUE are supported");
	}
	} catch (Exception e){
	throw new WayangException(e);
	}
	}


	@Override
	public void open(int taskNumber, int numTasks) throws IOException {
	try {
	if (taskNumber < 0 \|\| numTasks < 1) {
	throw new IllegalArgumentException("TaskNumber: " + taskNumber + ", numTasks: " + numTasks);
	}

	if (LOG.isDebugEnabled()) {
	LOG.debug("Opening stream for output (" + (taskNumber + 1) + "/" + numTasks + "). WriteMode=" + writeMode +
	", OutputDirectoryMode=" + outputDirectoryMode);
	}

	Path p = this.outputFilePath;
	if (p == null) {
	throw new IOException("The file path is null.");
	}

	final FileSystem fs = p.getFileSystem();

	if(fs.exists(p)) {
	fs.delete(p, true);
	}

	this.fileCreated = true;


	final SequenceFile.Writer.Option fileOption = SequenceFile.Writer.file(new org.apache.hadoop.fs.Path(p.toString()));
	final SequenceFile.Writer.Option keyClassOption = SequenceFile.Writer.keyClass(NullWritable.class);
	final SequenceFile.Writer.Option valueClassOption = SequenceFile.Writer.valueClass(BytesWritable.class);
	writer = SequenceFile.createWriter(new org.apache.hadoop.conf.Configuration(true), fileOption, keyClassOption, valueClassOption);
	}catch (Exception e){
	e.printStackTrace();
	}
	}

	@Override
	public void writeRecord(IT record) throws IOException {
	//this.blockBasedOutput.startRecord();
	try{
	ByteArrayOutputStream b = new ByteArrayOutputStream();
	ObjectOutputStream objStream = new ObjectOutputStream(b);
	objStream.writeObject(record);
	BytesWritable bytesWritable = new BytesWritable(b.toByteArray());
	writer.append(NullWritable.get(), bytesWritable);
	}catch (Exception e){
	e.printStackTrace();
	}
	}

	protected String getDirectoryFileName(int taskNumber) {
	return Integer.toString(taskNumber + 1);
	}

	@Override
	public void close() throws IOException {
	try {
	this.writer.close();
	DataOutputViewStreamWrapper o = this.outView;
	if (o != null) {
	o.close();
	}
	}
	finally {
	final FSDataOutputStream s = this.stream;
	if (s != null) {
	this.stream = null;
	s.close();
	}
	}
	}

	/**
	* Initialization of the distributed file system if it is used.
	*
	* @param parallelism The task parallelism.
	*/
	@Override
	public void initializeGlobal(int parallelism) throws IOException {
	try {
	final Path path = getOutputFilePath();
	final FileSystem fs = path.getFileSystem();

	// only distributed file systems can be initialized at start-up time.
	if (fs.isDistributedFS()) {

	final FileSystem.WriteMode writeMode = getWriteMode();
	final FileOutputFormat.OutputDirectoryMode outDirMode = getOutputDirectoryMode();

	if (parallelism == 1 && outDirMode == FileOutputFormat.OutputDirectoryMode.PARONLY) {
	// output is not written in parallel and should be written to a single file.
	// prepare distributed output path
	if (!fs.initOutPathDistFS(path, writeMode, false)) {
	// output preparation failed! Cancel task.
	throw new IOException("Output path could not be initialized.");
	}

	} else {
	// output should be written to a directory

	// only distributed file systems can be initialized at start-up time.
	if (!fs.initOutPathDistFS(path, writeMode, true)) {
	throw new IOException("Output directory could not be created.");
	}
	}
	}
	}catch (Exception e){
	throw new WayangException(e);
	}
	}

	@Override
	public void tryCleanupOnError() {
	if (this.fileCreated) {
	this.fileCreated = false;

	try {
	close();
	} catch (IOException e) {
	LOG.error("Could not properly close FileOutputFormat.", e);
	}

	try {
	FileSystem.get(this.actualFilePath.toUri()).delete(actualFilePath, false);
	} catch (FileNotFoundException e) {
	// ignore, may not be visible yet or may be already removed
	} catch (Throwable t) {
	LOG.error("Could not remove the incomplete file " + actualFilePath + '.', t);
	}
	}
	}

	/**
	* Writes a block info at the end of the blocks.<br>
	* Current implementation uses only int and not long.
	*
	*/
	protected class BlockBasedOutput extends FilterOutputStream {

	private static final int NO_RECORD = -1;

	private final int maxPayloadSize;

	private int blockPos;

	private int blockCount, totalCount;

	private long firstRecordStartPos = NO_RECORD;

	private BlockInfo blockInfo = WayangFileOutputFormat.this.createBlockInfo();

	private DataOutputView headerStream;

	public BlockBasedOutput(OutputStream out, int blockSize) {
	super(out);
	this.headerStream = new DataOutputViewStreamWrapper(out);
	this.maxPayloadSize = blockSize - this.blockInfo.getInfoSize();
	}

	@Override
	public void close() throws IOException {
	if (this.blockPos > 0) {
	this.writeInfo();
	}
	super.flush();
	super.close();
	}

	public void startRecord() {
	if (this.firstRecordStartPos == NO_RECORD) {
	this.firstRecordStartPos = this.blockPos;
	}
	this.blockCount++;
	this.totalCount++;
	}

	@Override
	public void write(byte[] b) throws IOException {
	this.write(b, 0, b.length);
	}

	@Override
	public void write(byte[] b, int off, int len) throws IOException {

	for (int remainingLength = len, offset = off; remainingLength > 0;) {
	int blockLen = Math.min(remainingLength, this.maxPayloadSize - this.blockPos);
	this.out.write(b, offset, blockLen);

	this.blockPos += blockLen;
	if (this.blockPos >= this.maxPayloadSize) {
	this.writeInfo();
	}
	remainingLength -= blockLen;
	offset += blockLen;
	}
	}

	@Override
	public void write(int b) throws IOException {
	super.write(b);
	if (++this.blockPos >= this.maxPayloadSize) {
	this.writeInfo();
	}
	}

	private void writeInfo() throws IOException {
	this.blockInfo.setRecordCount(this.blockCount);
	this.blockInfo.setAccumulatedRecordCount(this.totalCount);
	this.blockInfo.setFirstRecordStart(this.firstRecordStartPos == NO_RECORD ? 0 : this.firstRecordStartPos);
	WayangFileOutputFormat.this.complementBlockInfo(this.blockInfo);
	this.blockInfo.write(this.headerStream);
	this.blockPos = 0;
	this.blockCount = 0;
	this.firstRecordStartPos = NO_RECORD;
	}
	}
	protected BlockInfo createBlockInfo() {
	return new BlockInfo();
	}
	protected void complementBlockInfo(BlockInfo blockInfo) {}
	}