jhplot.io
Class HFile

java.lang.Object
  jhplot.io.HFile

public class HFile
extends Object

Write or read objects in sequential order using the Java serialization. The objects inside files are gzipped on-fly. The size of serialized files should be significantly smaller than when using HFile class. Use "close()" to flush buffered output stream. Use HFileBrowser to browser all entries in a GUI frame. Normally, files should extension "ser". Files can be viewed using HFileBrowser.

Field Summary

FileOutputStream	oof
ObjectOutputStream	oos
File	recordsFile

Constructor Summary

HFile(String file)
Open file for reading objects from a serialized file in sequential order.

HFile(String file, String option)
Open file for reading objects from a serialized file in sequential order.

HFile(String file, String option, boolean compression)
Open a file to write/read objects to/from a serialized file in sequential order.

HFile(String file, String option, boolean compression, int bufferSize)
Open a file to write/read objects to/from a serialized file in sequential order.

Method Summary

boolean	close() Close the file
int	getBufferSize() Get current buffer size for I/O.
int	getEntries() Return processed number of entries
Object	read() Get object from a file.
void	setFlush(int reset) Set after how many events data will be flushed.
boolean	write(Object ob) Add an object to a file

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

recordsFile

public File recordsFile

oof

public FileOutputStream oof

oos

public ObjectOutputStream oos

Constructor Detail

HFile

public HFile(String file,
             String option,
             boolean compression,
             int bufferSize)

Open a file to write/read objects to/from a serialized file in sequential order. Objects can be gzipped/gunzipped on-fly. If "w" option is set, the old file will be removed. Use close() to flash the buffer and close the file. You can set buffer size for I/O . Make it larger for a heavy I/O. It is best to use buffer sizes that are multiples of 1024 bytes. That works best with most built-in buffering in hard disks

Parameters:

file - File name

option - Option to create the file. If "w" - write a file (or read) file, if "r" only read created file.

compression - if true, objects are compressed on-fly using GZIP

bufferSize - set buffer size for I/O. It is best to use buffer sizes that are multiples of 1024 bytes.

HFile

public HFile(String file,
             String option,
             boolean compression)

Open a file to write/read objects to/from a serialized file in sequential order. Objects can be gzipped/gunzipped on-fly. If "w" option is set, the old file will be removed. Use close() to flash the buffer and close the file. The default buffer size is 12 k (i.e. 12 * 1024).

Parameters:

file - File name

option - Option to create the file. If "w" - write a file (or read) file, if "r" only read created file.

compression - if true, objects are compressed on-fly using GZIP

buffer - set buffer size for I/O. It is best to use buffer sizes that are multiples of 1024 bytes.

HFile

public HFile(String file)

Open file for reading objects from a serialized file in sequential order. By default, entries are compressed.

Parameters:

file - File name

HFile

public HFile(String file,
             String option)

Open file for reading objects from a serialized file in sequential order. By default, objects are compressed.

Parameters:

file - File name

option - Option to create the file. If "w" - write a file (or read) file, if "r" only read created file.

Method Detail

getBufferSize

public int getBufferSize()

Get current buffer size for I/O.

write

public boolean write(Object ob)

Add an object to a file

Parameters:

ob - Object

key - key for object

Returns:

true if success

setFlush

public void setFlush(int reset)

Set after how many events data will be flushed. The stream will flush all the objects from the identity hash table. The default is 100.

Parameters:

reset - after how many events data will be reset.

getEntries

public int getEntries()

Return processed number of entries

Returns:

No of processed events

read

public Object read()

Get object from a file. Return Null if the end if file is reached.

Returns:

Object extracted object (or Null)

close

public boolean close()

Close the file

Returns: