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 BrowserHFile to browser all entries in a GUI frame. Normally, files should have the extension ".jser". Files can be viewed using BrowserHFile.
You can also insert objects using the keys and read them back. In this case, avoid writing many objects without the keys since the extraction of keys will be very inefficient. Try not mix write/read with keys or without.

Constructor Summary

Constructors
Constructor and Description
`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

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`close()` Close the file
`void`	`doc()` Show online documentation.
`int`	`getBufferSize()` Get current buffer size for I/O.
`int`	`getEntries()` Return processed number of entries.
`Map<String,Object>`	`getObjectMap()` Return objects stored in the form of a map.
`Object`	`read()` Get object from a file.
`Object`	`read(String key)` Read an object using a key if exits.
`void`	`setFlush(int reset)` Set after how many events data will be flushed.
`boolean`	`write(Object ob)` Add an object to a file
`boolean`	`write(String key, Object ob)` Add an object using a key.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 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.
    You can also insert an object using a string key.
    If the file name starts from http or ftp, we assume it is located on the Web and will attempt to read it from URL.
    
    Parameters:
    
    file - File name. Can be located on URL if starts from http or ftp.
    
    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(String key,
                     Object ob)
```
    Add an object using a key.
    
    Parameters:
    
    key - key to access the object.
    
    ob - object to be inserted.
    
    Returns:
    
    false if the key exits.
  - 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.
  - getObjectMap
```
public Map<String,Object> getObjectMap()
```
    Return objects stored in the form of a map.
    
    Returns:
  - getEntries
```
public int getEntries()
```
    Return processed number of entries. Entries with the key not counted.
    
    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)
  - read
```
public Object read(String key)
```
    Read an object using a key if exits.
    
    Parameters:
    
    key -
    
    Returns:
    
    returned object.
  - close
```
public boolean close()
```
    Close the file
    
    Returns:
  - doc
```
public void doc()
```
    Show online documentation.

Class HFile

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

HFile

HFile

HFile

HFile

Method Detail

getBufferSize

write

write

setFlush

getObjectMap

getEntries

read

read

close

doc