WriterOutputStream (Apache Commons IO 2.7 API)

java.lang.Object
- java.io.OutputStream
- - org.apache.commons.io.output.WriterOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable
```
public class WriterOutputStream
extends OutputStream
```
OutputStream implementation that transforms a byte stream to a character stream using a specified charset encoding and writes the resulting stream to a Writer. The stream is transformed using a CharsetDecoder object, guaranteeing that all charset encodings supported by the JRE are handled correctly.
The output of the CharsetDecoder is buffered using a fixed size buffer. This implies that the data is written to the underlying Writer in chunks that are no larger than the size of this buffer. By default, the buffer is flushed only when it overflows or when flush() or close() is called. In general there is therefore no need to wrap the underlying Writer in a BufferedWriter. WriterOutputStream can also be instructed to flush the buffer after each write operation. In this case, all available data is written immediately to the underlying Writer, implying that the current position of the Writer is correlated to the current position of the WriterOutputStream.
WriterOutputStream implements the inverse transformation of OutputStreamWriter; in the following example, writing to out2 would have the same result as writing to out directly (provided that the byte sequence is legal with respect to the charset encoding):
```
 OutputStream out = ...
 Charset cs = ...
 OutputStreamWriter writer = new OutputStreamWriter(out, cs);
 WriterOutputStream out2 = new WriterOutputStream(writer, cs);
```
WriterOutputStream implements the same transformation as InputStreamReader, except that the control flow is reversed: both classes transform a byte stream into a character stream, but InputStreamReader pulls data from the underlying stream, while WriterOutputStream pushes it to the underlying stream.
Note that while there are use cases where there is no alternative to using this class, very often the need to use this class is an indication of a flaw in the design of the code. This class is typically used in situations where an existing API only accepts an OutputStream object, but where the stream is known to represent character data that must be decoded for further use.
Instances of WriterOutputStream are not thread safe.
Since:

2.0

See Also:

ReaderInputStream

Constructor Summary

Constructors
Constructor and Description
`WriterOutputStream(Writer writer)` Deprecated. 2.5 use `WriterOutputStream(Writer, Charset)` instead
`WriterOutputStream(Writer writer, Charset charset)` Constructs a new `WriterOutputStream` with a default output buffer size of characters.
`WriterOutputStream(Writer writer, CharsetDecoder decoder)` Constructs a new `WriterOutputStream` with a default output buffer size of characters.
`WriterOutputStream(Writer writer, CharsetDecoder decoder, int bufferSize, boolean writeImmediately)` Constructs a new `WriterOutputStream`.
`WriterOutputStream(Writer writer, Charset charset, int bufferSize, boolean writeImmediately)` Constructs a new `WriterOutputStream`.
`WriterOutputStream(Writer writer, String charsetName)` Constructs a new `WriterOutputStream` with a default output buffer size of characters.
`WriterOutputStream(Writer writer, String charsetName, int bufferSize, boolean writeImmediately)` Constructs a new `WriterOutputStream`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Close the stream.
`void`	`flush()` Flush the stream.
`void`	`write(byte[] b)` Write bytes from the specified byte array to the stream.
`void`	`write(byte[] b, int off, int len)` Write bytes from the specified byte array to the stream.
`void`	`write(int b)` Write a single byte to the stream.

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

- Constructor Detail
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          CharsetDecoder decoder)
```
    Constructs a new WriterOutputStream with a default output buffer size of characters. The output buffer will only be flushed when it overflows or when flush() or close() is called.
    
    Parameters:
    
    writer - the target Writer
    
    decoder - the charset decoder
    
    Since:
    
    2.1
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          CharsetDecoder decoder,
                          int bufferSize,
                          boolean writeImmediately)
```
    Constructs a new WriterOutputStream.
    
    Parameters:
    
    writer - the target Writer
    
    decoder - the charset decoder
    
    bufferSize - the size of the output buffer in number of characters
    
    writeImmediately - If true the output buffer will be flushed after each write operation, i.e. all available data will be written to the underlying Writer immediately. If false, the output buffer will only be flushed when it overflows or when flush() or close() is called.
    
    Since:
    
    2.1
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          Charset charset,
                          int bufferSize,
                          boolean writeImmediately)
```
    Constructs a new WriterOutputStream.
    
    Parameters:
    
    writer - the target Writer
    
    charset - the charset encoding
    
    bufferSize - the size of the output buffer in number of characters
    
    writeImmediately - If true the output buffer will be flushed after each write operation, i.e. all available data will be written to the underlying Writer immediately. If false, the output buffer will only be flushed when it overflows or when flush() or close() is called.
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          Charset charset)
```
    Constructs a new WriterOutputStream with a default output buffer size of characters. The output buffer will only be flushed when it overflows or when flush() or close() is called.
    
    Parameters:
    
    writer - the target Writer
    
    charset - the charset encoding
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          String charsetName,
                          int bufferSize,
                          boolean writeImmediately)
```
    Constructs a new WriterOutputStream.
    
    Parameters:
    
    writer - the target Writer
    
    charsetName - the name of the charset encoding
    
    bufferSize - the size of the output buffer in number of characters
    
    writeImmediately - If true the output buffer will be flushed after each write operation, i.e. all available data will be written to the underlying Writer immediately. If false, the output buffer will only be flushed when it overflows or when flush() or close() is called.
  - WriterOutputStream
```
public WriterOutputStream(Writer writer,
                          String charsetName)
```
    Constructs a new WriterOutputStream with a default output buffer size of characters. The output buffer will only be flushed when it overflows or when flush() or close() is called.
    
    Parameters:
    
    writer - the target Writer
    
    charsetName - the name of the charset encoding
  - WriterOutputStream
```
@Deprecated
public WriterOutputStream(Writer writer)
```
    Deprecated. 2.5 use WriterOutputStream(Writer, Charset) instead
    
    Constructs a new WriterOutputStream that uses the default character encoding and with a default output buffer size of characters. The output buffer will only be flushed when it overflows or when flush() or close() is called.
    
    Parameters:
    
    writer - the target Writer
- Method Detail
  - write
```
public void write(byte[] b,
                  int off,
                  int len)
           throws IOException
```
    Write bytes from the specified byte array to the stream.
    
    Overrides:
    
    write in class OutputStream
    
    Parameters:
    
    b - the byte array containing the bytes to write
    
    off - the start offset in the byte array
    
    len - the number of bytes to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(byte[] b)
           throws IOException
```
    Write bytes from the specified byte array to the stream.
    
    Overrides:
    
    write in class OutputStream
    
    Parameters:
    
    b - the byte array containing the bytes to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - write
```
public void write(int b)
           throws IOException
```
    Write a single byte to the stream.
    
    Specified by:
    
    write in class OutputStream
    
    Parameters:
    
    b - the byte to write
    
    Throws:
    
    IOException - if an I/O error occurs
  - flush
```
public void flush()
           throws IOException
```
    Flush the stream. Any remaining content accumulated in the output buffer will be written to the underlying Writer. After that Writer.flush() will be called.
    
    Specified by:
    
    flush in interface Flushable
    
    Overrides:
    
    flush in class OutputStream
    
    Throws:
    
    IOException - if an I/O error occurs
  - close
```
public void close()
           throws IOException
```
    Close the stream. Any remaining content accumulated in the output buffer will be written to the underlying Writer. After that Writer.close() will be called.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Overrides:
    
    close in class OutputStream
    
    Throws:
    
    IOException - if an I/O error occurs

Class WriterOutputStream

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

WriterOutputStream

WriterOutputStream

WriterOutputStream

WriterOutputStream

WriterOutputStream

WriterOutputStream

WriterOutputStream

Method Detail

write

write

write

flush

close