Hi,A ContentReader or ContentWriter cannot be reused. The underlying Channel on a reader or writer can only be created once. Certain operations access the channel and close it automatically (e.g. putFile and getFile), but if you access the channel or stream directly then you are responsible for closing it. However, you can request a new reader from either a reader or writer using #getReader. Be sure to close the output channelbefore using this method on a ContentWriter.I'm just going to type here, so forgive any obvious issues:
ContentService contentService; // by Spring injection
ContentReader sourceReader; // passed in
ContentWriter targetWriter; // passed in
// do the stuff with the source stream
…
List<ContentReader> innerReaders = new ArrayList<ContentReader>(5);
// some kind of loop
…
{
String innerMimetype = …; // you get it somehow
// use the temp writer so that the file will be cleaned up
ContentWriter innerSource = contentService.getTempWriter();
// fill it with the inner document. Be sure to close the stream if you accessed it directly.
…
// get a target to transform to
ContentWriter innerTarget = contentService.getTempWriter();
// now transform
ContentTransformer innerToTextTransformer = contentTransformerRegistry.getTransformer(innerMimetype, MimetypeMap.TEXT_PLAIN);
innerToTextTransformer.transform(innerSource.getReader(), innerTarget);
// add the target to the list of readers
innerReaders.add(innerTarget.getReader());
}
// now you have a list of readers that are the text version of all inner documents
OutputStream targetos = null;
try
{
// write the stream to the output target.
targetOs = targetWriter.getOutputStream(); // can only do this once
for (ContentReader innerReader: innerReaders)
{
// you can't use targetWriter.putContent(innerReader) because, as the javadoc states,
// the ouput channel will be closed and the reader and writer may only be used once
InputStream innerSourceIs = innerReader.getInputStream();
copy(innerSourceIs, targetOs); // inner source input stream will be closed
}
}
finally
{
// close the output stream
…
}
// done
/**
* Copies the input stream to the output stream, closing only the input stream upon completion
*/
private void copy(InputStream is, OutputStream os)
{
// see Spring FileCopyUtils for example code, if required
…
}
I hope it helps.
