LockableFileWriter (Apache Commons IO 2.5 API)

java.lang.Object
- java.io.Writer
- - org.apache.commons.io.output.LockableFileWriter

All Implemented Interfaces:

Closeable, Flushable, Appendable, AutoCloseable
```
public class LockableFileWriter
extends Writer
```
FileWriter that will create and honor lock files to allow simple cross thread file lock handling.
This class provides a simple alternative to FileWriter that will use a lock file to prevent duplicate writes.
N.B. the lock file is deleted when close() is called - or if the main file cannot be opened initially. In the (unlikely) event that the lockfile cannot be deleted, this is not reported, and subsequent requests using the same lockfile will fail.
By default, the file will be overwritten, but this may be changed to append. The lock directory may be specified, but defaults to the system property java.io.tmpdir. The encoding may also be specified, and defaults to the platform default.

Version:

$Id: LockableFileWriter.java 1686747 2015-06-21 18:44:49Z krosenvold $

Field Summary
- Fields inherited from class java.io.Writer
  lock

Constructor Summary

Constructors
Constructor and Description
`LockableFileWriter(File file)` Constructs a LockableFileWriter.
`LockableFileWriter(File file, boolean append)` Constructs a LockableFileWriter.
`LockableFileWriter(File file, boolean append, String lockDir)` Deprecated. 2.5 use `LockableFileWriter(File, Charset, boolean, String)` instead
`LockableFileWriter(File file, Charset encoding)` Constructs a LockableFileWriter with a file encoding.
`LockableFileWriter(File file, Charset encoding, boolean append, String lockDir)` Constructs a LockableFileWriter with a file encoding.
`LockableFileWriter(File file, String encoding)` Constructs a LockableFileWriter with a file encoding.
`LockableFileWriter(File file, String encoding, boolean append, String lockDir)` Constructs a LockableFileWriter with a file encoding.
`LockableFileWriter(String fileName)` Constructs a LockableFileWriter.
`LockableFileWriter(String fileName, boolean append)` Constructs a LockableFileWriter.
`LockableFileWriter(String fileName, boolean append, String lockDir)` Constructs a LockableFileWriter.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Closes the file writer and deletes the lockfile (if possible).
`void`	`flush()` Flush the stream.
`void`	`write(char[] chr)` Write the characters from an array.
`void`	`write(char[] chr, int st, int end)` Write the specified characters from an array.
`void`	`write(int idx)` Write a character.
`void`	`write(String str)` Write the characters from a string.
`void`	`write(String str, int st, int end)` Write the specified characters from a string.

Methods inherited from class java.io.Writer
append, append, append

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

- Constructor Detail
  - LockableFileWriter
```
public LockableFileWriter(String fileName)
                   throws IOException
```
    Constructs a LockableFileWriter. If the file exists, it is overwritten.
    
    Parameters:
    fileName - the file to write to, not null
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
public LockableFileWriter(String fileName,
                  boolean append)
                   throws IOException
```
    Constructs a LockableFileWriter.
    
    Parameters:
    fileName - file to write to, not null
    append - true if content should be appended, false to overwrite
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
public LockableFileWriter(String fileName,
                  boolean append,
                  String lockDir)
                   throws IOException
```
    Constructs a LockableFileWriter.
    
    Parameters:
    fileName - the file to write to, not null
    append - true if content should be appended, false to overwrite
    lockDir - the directory in which the lock file should be held
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
public LockableFileWriter(File file)
                   throws IOException
```
    Constructs a LockableFileWriter. If the file exists, it is overwritten.
    
    Parameters:
    file - the file to write to, not null
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
public LockableFileWriter(File file,
                  boolean append)
                   throws IOException
```
    Constructs a LockableFileWriter.
    
    Parameters:
    file - the file to write to, not null
    append - true if content should be appended, false to overwrite
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
@Deprecated
public LockableFileWriter(File file,
                             boolean append,
                             String lockDir)
                   throws IOException
```
    Deprecated. 2.5 use LockableFileWriter(File, Charset, boolean, String) instead
    
    Constructs a LockableFileWriter.
    
    Parameters:
    file - the file to write to, not null
    append - true if content should be appended, false to overwrite
    lockDir - the directory in which the lock file should be held
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
  - LockableFileWriter
```
public LockableFileWriter(File file,
                  Charset encoding)
                   throws IOException
```
    Constructs a LockableFileWriter with a file encoding.
    
    Parameters:
    file - the file to write to, not null
    encoding - the encoding to use, null means platform default
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
    Since:
    
    2.3
  - LockableFileWriter
```
public LockableFileWriter(File file,
                  String encoding)
                   throws IOException
```
    Constructs a LockableFileWriter with a file encoding.
    
    Parameters:
    file - the file to write to, not null
    encoding - the encoding to use, null means platform default
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
    
    UnsupportedCharsetException - thrown instead of UnsupportedEncodingException in version 2.2 if the encoding is not supported.
  - LockableFileWriter
```
public LockableFileWriter(File file,
                  Charset encoding,
                  boolean append,
                  String lockDir)
                   throws IOException
```
    Constructs a LockableFileWriter with a file encoding.
    
    Parameters:
    file - the file to write to, not null
    encoding - the encoding to use, null means platform default
    append - true if content should be appended, false to overwrite
    lockDir - the directory in which the lock file should be held
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
    Since:
    
    2.3
  - LockableFileWriter
```
public LockableFileWriter(File file,
                  String encoding,
                  boolean append,
                  String lockDir)
                   throws IOException
```
    Constructs a LockableFileWriter with a file encoding.
    
    Parameters:
    file - the file to write to, not null
    encoding - the encoding to use, null means platform default
    append - true if content should be appended, false to overwrite
    lockDir - the directory in which the lock file should be held
    
    Throws:
    
    NullPointerException - if the file is null
    
    IOException - in case of an I/O error
    
    UnsupportedCharsetException - thrown instead of UnsupportedEncodingException in version 2.2 if the encoding is not supported.
- Method Detail
  - close
```
public void close()
           throws IOException
```
    Closes the file writer and deletes the lockfile (if possible).
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Specified by:
    
    close in class Writer
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(int idx)
           throws IOException
```
    Write a character.
    
    Overrides:
    
    write in class Writer
    
    Parameters:
    idx - the character to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(char[] chr)
           throws IOException
```
    Write the characters from an array.
    
    Overrides:
    
    write in class Writer
    
    Parameters:
    chr - the characters to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(char[] chr,
         int st,
         int end)
           throws IOException
```
    Write the specified characters from an array.
    
    Specified by:
    
    write in class Writer
    
    Parameters:
    chr - the characters to write
    st - The start offset
    end - The number of characters to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(String str)
           throws IOException
```
    Write the characters from a string.
    
    Overrides:
    
    write in class Writer
    
    Parameters:
    str - the string to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(String str,
         int st,
         int end)
           throws IOException
```
    Write the specified characters from a string.
    
    Overrides:
    
    write in class Writer
    
    Parameters:
    str - the string to write
    st - The start offset
    end - The number of characters to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - flush
```
public void flush()
           throws IOException
```
    Flush the stream.
    
    Specified by:
    
    flush in interface Flushable
    
    Specified by:
    
    flush in class Writer
    
    Throws:
    
    IOException - if an I/O error occurs

Class LockableFileWriter

Field Summary

Fields inherited from class java.io.Writer

Constructor Summary

Method Summary

Methods inherited from class java.io.Writer

Methods inherited from class java.lang.Object

Constructor Detail

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

LockableFileWriter

Method Detail

close

write

write

write

write

write

flush