Support OpenPDF 3.0

[jakeab]

AbstractPdfView
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/servlet/view/document/AbstractPdfView.html

references classes from the com.lowagie hierarchy for compatibility with iText and OpenPDF. OpenPDF 3.0 has changed its package name:

OpenPDF 3.0.0 uses the new package name org.openpdf. The old com.lowagie is now removed from OpenPDF 3.0.
This means that source code using OpenPDF must be migrated to use import statements using org.openpdf.* package.

https://github.com/LibrePDF/OpenPDF/releases

A possible wrinkle: OpenPDF in 2.1.0 moved to a Java 21 compiler level.

[bclozel]

I don't think we can safely support this option since Java 21 is required and we have a Java 17 baseline. Maybe we should retire this view from Framework and let the community ship a separate dependency for this use case.

[bclozel]

We discussed this today and decided to close this issue in favor of #35451.

While this is probably not the outcome your expected @jakeab , we think that the entire package is outdated and that this should be supported in a different way. We won't add support for OpenPDF 3.0 and we think that a dedicated View implementation (like many other projects do) would be a better solution overall.

Thanks!

[jakeab]

@bclozel I'm not too surprised and that's fine by me. (Our code in this area is quite old.) I appreciate the fast reply, thank you!

[andreasrosdal]

May I suggest cooperation with the OpenPDF project, so they understand the requirements of the Spring framework. I think OpenPDF is a fine PDF library for Java, and I am sure the developers of OpenPDF would gladly help make changes to be suitable for the spring framework, if I may say so myself. OpenPDF 3.0 requires Java 21 in order to encourage using the modern features of Java 21, and I would like to encourage the spring framework to help promote Java 21 usage as well.

[bclozel]

@andreasrosdal that's a neat idea. From my experience, such requests are more likely to be accepted if they come from actual users willing to contribute or test implementations in actual projects.

Feel free to create a PR or issue on that project. I would be happy to provide guidance if the maintainers are interested.