org.apache.tika.io
Class TaggedInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          org.apache.tika.io.ProxyInputStream
              org.apache.tika.io.TaggedInputStream

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

TikaInputStream

public class TaggedInputStream
extends ProxyInputStream

An input 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.

 TaggedInputStream stream = new TaggedInputStream(...);
 try {
     // Processing that may throw an IOException either from this stream
     // or from some other IO activity like temporary files, etc.
     processStream(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.

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

See Also:

TaggedIOException

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

TaggedInputStream(InputStream proxy)
Creates a tagging decorator for the given input stream.

Method Summary

static TaggedInputStream	get(InputStream proxy) Casts or wraps the given stream to a TaggedInputStream instance.
protected void	handleIOException(IOException e) Tags any IOExceptions thrown, wrapping and re-throwing.
boolean	isCauseOf(IOException exception) Tests if the given exception was caused by this stream.
void	throwIfCauseOf(Exception exception) Re-throws the original exception thrown by this stream.
String	toString()

Methods inherited from class org.apache.tika.io.ProxyInputStream

afterRead, available, beforeRead, close, mark, markSupported, read, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

TaggedInputStream

public TaggedInputStream(InputStream proxy)

Creates a tagging decorator for the given input stream.

Parameters:

proxy - input stream to be decorated

Method Detail

get

public static TaggedInputStream get(InputStream proxy)

Casts or wraps the given stream to a TaggedInputStream instance.

Parameters:

stream - normal input stream

Returns:

a TaggedInputStream instance

isCauseOf

public boolean isCauseOf(IOException 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

handleIOException

protected void handleIOException(IOException e)
                          throws IOException

Tags any IOExceptions thrown, wrapping and re-throwing.

Overrides:

handleIOException in class ProxyInputStream

Parameters:

e - The IOException thrown

Throws:

IOException - if an I/O error occurs

toString

public String toString()

Overrides:

toString in class Object