Package org.apache.commons.io.output

# Class TaggedOutputStream

java.lang.Object
java.io.OutputStream
java.io.FilterOutputStream
org.apache.commons.io.output.ProxyOutputStream
org.apache.commons.io.output.TaggedOutputStream

All Implemented Interfaces:
  `Closeable`, `Flushable`, `AutoCloseable`

public class TaggedOutputStream extends ProxyOutputStream
An output stream decorator that tags potential exceptions so that the stream that caused the exception can easily be identified. This is done by using the `TaggedIOException` class to wrap all thrown `IOException`s. See below for an example of using this class.

     TaggedOutputStream stream = new TaggedOutputStream(...);
     try {
         // Processing that may throw an IOException either from this stream
         // or from some other IO activity like temporary files, etc.
         writeToStream(stream);
     } catch (IOException e) {
         if (stream.isCauseOf(e)) {
             // The exception was caused by this stream.
             // Use e.getCause() to get the original exception.
         } else {
             // The exception was caused by something else.
         }
     }

Alternatively, the `throwIfCauseOf(Exception)` method can be used to let higher levels of code handle the exception caused by this stream while other processing errors are being taken care of at this lower level.

     TaggedOutputStream stream = new TaggedOutputStream(...);
     try {
         writeToStream(stream);
     } catch (IOException e) {
         stream.throwIfCauseOf(e);
         // ... or process the exception that was caused by something else
     }

Since:
  2.0
See Also:
  - `TaggedIOException`

- ## Field Summary

  ### Fields inherited from class java.io.FilterOutputStream

  `out`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `TaggedOutputStream(OutputStream proxy)`
  Constructs a tagging decorator for the given output stream.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `protected void`
  `handleIOException(IOException e)`
  Tags any IOExceptions thrown, wrapping and re-throwing.
  `boolean`
  `isCauseOf(Exception exception)`
  Tests if the given exception was caused by this stream.
  `void`
  `throwIfCauseOf(Exception exception)`
  Re-throws the original exception thrown by this stream.

  ### Methods inherited from class org.apache.commons.io.output.ProxyOutputStream

  `afterWrite, beforeWrite, close, flush, write, write, write`

  ### Methods inherited from class java.lang.Object

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

- ## Constructor Details

  - ### TaggedOutputStream

    public TaggedOutputStream(OutputStream proxy)
    Constructs a tagging decorator for the given output stream.
    Parameters:
      `proxy` - output stream to be decorated

- ## Method Details

  - ### handleIOException

    protected void handleIOException(IOException e) throws IOException
    Tags any IOExceptions thrown, wrapping and re-throwing.
    Overrides:
      `handleIOException` in class `ProxyOutputStream`
    Parameters:
      `e` - The IOException thrown
    Throws:
      `IOException` - if an I/O error occurs.

  - ### isCauseOf

    public boolean isCauseOf(Exception exception)
    Tests if the given exception was caused by this stream.
    Parameters:
      `exception` - an exception
    Returns:
      `true` if the exception was thrown by this stream, `false` otherwise

  - ### throwIfCauseOf

    public void throwIfCauseOf(Exception exception) throws IOException
    Re-throws the original exception thrown by this stream. This method first checks whether the given exception is a `TaggedIOException` wrapper created by this decorator, and then unwraps and throws the original wrapped exception. Returns normally if the exception was not thrown by this stream.
    Parameters:
      `exception` - an exception
    Throws:
      `IOException` - original exception, if any, thrown by this stream