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 IOExceptions. 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:

  • 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