/**
* @see
* org.alfresco.repo.content.transform.AbstractContentTransformer2#transformInternal(org.alfresco.service.cmr.repository.ContentReader,
* org.alfresco.service.cmr.repository.ContentWriter,
* org.alfresco.service.cmr.repository.TransformationOptions)
*/
@Override
public void transformInternal(
ContentReader reader, ContentWriter writer, TransformationOptions options) throws Exception {
final String outputMimetype = writer.getMimetype();
final String outputFileExt = getMimetypeService().getExtension(outputMimetype);
// We need to keep a reference to thrown exceptions as we're going to catch them and
// then move on to the next transformer. In the event that they all fail, we will throw
// the final exception.
Exception transformationException = null;
for (int i = 0; i < transformers.size(); i++) {
int oneBasedCount = i + 1;
ContentTransformer transf = transformers.get(i);
ContentWriter currentWriter = null;
File tempFile = null;
try {
if (logger.isDebugEnabled()) {
logger.debug(
"Transformation attempt "
+ oneBasedCount
+ " of "
+ transformers.size()
+ ": "
+ transf);
}
if (!transf.isTransformable(
reader.getMimetype(), reader.getSize(), outputMimetype, options)) {
throw new UnsupportedTransformationException(
"Unsupported transformation: " + reader.getMimetype() + " to " + outputMimetype);
}
// We can't know in advance which transformer in the sequence will work - if any.
// Therefore we can't write into the ContentWriter stream.
// So make a temporary file writer with the current transformer name.
tempFile =
TempFileProvider.createTempFile(
"FailoverTransformer_intermediate_" + transf.getClass().getSimpleName() + "_",
"." + outputFileExt);
currentWriter = new FileContentWriter(tempFile);
currentWriter.setMimetype(outputMimetype);
currentWriter.setEncoding(writer.getEncoding());
// attempt to transform
transf.transform(reader, currentWriter, options);
// TODO Could add a check for zero-length output and treat that as a failure
// final long writtenSize = currentWriter.getSize();
} catch (Exception are) {
if (transformationException == null) {
transformationException = are;
}
if (logger.isDebugEnabled()) {
logger.debug("Transformation " + oneBasedCount + " was unsuccessful.");
if (i != transformers.size() - 1) {
// We don't log the last exception as we're going to throw it.
logger.debug("The below exception is provided for information purposes only.", are);
}
}
// Set a new reader to refresh the input stream.
reader = reader.getReader();
// and move to the next transformer
continue;
}
// No need to close input or output streams
// At this point the current transformation was successful i.e. it did not throw an exception.
// Now we must copy the content from the temporary file into the ContentWriter stream.
if (tempFile != null) {
writer.putContent(tempFile);
}
if (logger.isInfoEnabled()) {
logger.info("Transformation was successful");
}
return;
}
// At this point we have tried all transformers in the sequence without apparent success.
if (transformationException != null) {
transformerDebug.debug(" No more transformations to failover to");
if (logger.isDebugEnabled()) {
logger.debug(
"All transformations were unsuccessful. Throwing first exception.",
transformationException);
}
throw transformationException;
}
}
