Thursday, September 08, 2022

Java Freemarker with Domino

There are plenty of different Java template engines but for last years I used to stick to FreeMarker. It's open sourced and licensed under the Apache License, Version 2.0.

Here I only want to demonstrate how to integrate it with Domino nicely as it requires to write TemplateLoader class.

Build result based on tempalte "page"
Configuration cfg = new Configuration(Configuration.VERSION_2_3_31);
cfg.setDefaultEncoding("UTF-8");
cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
cfg.setLogTemplateExceptions(false);

Get the template (uses cache internally)
DominoTemplateLoader dominoLoader = new DominoTemplateLoader(getDatabase());
cfg.setTemplateLoader(dominoLoader);

Template template = cfg.getTemplate("page");

/* Merge data-model with template */
HashMap tags = new HashMap();
tags.put("title", "hellow world");
tags.put("description", "Neque porro quisquam est qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.");
			
Writer out = new StringWriter();
template.process(tags, out);
String html = out.toString();
The most important part was actually to build DominoTemplateLoader class and below you can see it
public class DominoTemplateLoader implements TemplateLoader {
	private View m_view;

	public DominoTemplateLoader(Database database) throws NotesException {
		m_view = database.getView("($Template)");
	}

	public void closeTemplateSource(Object templateSource) throws IOException {
		Document doc = (Document) templateSource;
		try {
			doc.recycle();
		} catch (NotesException e) {
			e.printStackTrace();
		}
	}

	public Object findTemplateSource(String id) throws IOException {
		try {
			return m_view.getDocumentByKey(id, true);
		} catch (NotesException e) {
			e.printStackTrace();
		}

		return null;
	}

	public long getLastModified(Object templateSource) {
		Document doc = (Document) templateSource;

		try {
			return doc.getLastModified().toJavaDate().getTime();
		} catch (NotesException e) {
			e.printStackTrace();
		}

		return 0;
	}

	public Reader getReader(Object templateSource, String encoding) throws IOException {
		if (templateSource == null) return null;
		
		Document doc = (Document) templateSource;
		try {
			return doc.getFirstItem("Body").getReader();
		} catch (NotesException e) {
			e.printStackTrace();
		}
		return null;
	}
}
As you can see the Loader class get document form a view and simply get data from item Body.

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