From 333b2dd0c58701683c1d24ef86bd1abd676a9a46 Mon Sep 17 00:00:00 2001
From: Tobias Kuhn <kuhntobias@gmail.com>
Date: Wed, 19 Apr 2017 08:42:09 +0200
Subject: [PATCH] Support for temporary URIs that are replaced during
 trustification

---
 .../org/nanopub/trusty/MakeTrustyNanopub.java | 11 ++-
 .../org/nanopub/trusty/TempUriReplacer.java   | 77 +++++++++++++++++++
 2 files changed, 86 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/org/nanopub/trusty/TempUriReplacer.java

diff --git a/src/main/java/org/nanopub/trusty/MakeTrustyNanopub.java b/src/main/java/org/nanopub/trusty/MakeTrustyNanopub.java
index d249a68..aabad2e 100644
--- a/src/main/java/org/nanopub/trusty/MakeTrustyNanopub.java
+++ b/src/main/java/org/nanopub/trusty/MakeTrustyNanopub.java
@@ -99,9 +99,16 @@ public static Nanopub transform(Nanopub nanopub) throws TrustyUriException {
 		}
 		try {
 			RdfFileContent r = new RdfFileContent(RDFFormat.TRIG);
-			NanopubUtils.propagateToHandler(nanopub, r);
+			String npUri;
+			if (TempUriReplacer.hasTempUri(nanopub)) {
+				npUri = TempUriReplacer.normUri;
+				NanopubUtils.propagateToHandler(nanopub, new TempUriReplacer(nanopub, r));
+			} else {
+				npUri = nanopub.getUri().toString();
+				NanopubUtils.propagateToHandler(nanopub, r);
+			}
 			NanopubRdfHandler h = new NanopubRdfHandler();
-			TransformRdf.transform(r, h, nanopub.getUri().toString());
+			TransformRdf.transform(r, h, npUri);
 			np = h.getNanopub();
 		} catch (RDFHandlerException ex) {
 			throw new TrustyUriException(ex);
diff --git a/src/main/java/org/nanopub/trusty/TempUriReplacer.java b/src/main/java/org/nanopub/trusty/TempUriReplacer.java
new file mode 100644
index 0000000..4242e81
--- /dev/null
+++ b/src/main/java/org/nanopub/trusty/TempUriReplacer.java
@@ -0,0 +1,77 @@
+package org.nanopub.trusty;
+
+import org.nanopub.Nanopub;
+import org.openrdf.model.Resource;
+import org.openrdf.model.Statement;
+import org.openrdf.model.URI;
+import org.openrdf.model.Value;
+import org.openrdf.model.impl.ContextStatementImpl;
+import org.openrdf.model.impl.URIImpl;
+import org.openrdf.rio.RDFHandler;
+import org.openrdf.rio.RDFHandlerException;
+
+/**
+ * You can use temporary URIs for your nanopublications that start with
+ * "http://purl.org/nanopub/temp/". These then become short "http://purl.org/np/"
+ * when they are transformed to trusty nanopublications.
+ *
+ * @author Tobias Kuhn
+ */
+public class TempUriReplacer implements RDFHandler {
+
+	public static final String tempUri = "http://purl.org/nanopub/temp/";
+	public static final String normUri = "http://purl.org/np/";
+
+	private String uriPrefix;
+	private RDFHandler nestedHandler;
+
+	public TempUriReplacer(Nanopub np, RDFHandler nestedHandler) {
+		uriPrefix = np.getUri().stringValue();
+		this.nestedHandler = nestedHandler;
+	}
+
+	public static boolean hasTempUri(Nanopub np) {
+		return np.getUri().stringValue().startsWith(tempUri);
+	}
+
+	@Override
+	public void handleStatement(Statement st) throws RDFHandlerException {
+		nestedHandler.handleStatement(new ContextStatementImpl(
+				(Resource) replace(st.getSubject()),
+				(URI) replace(st.getPredicate()),
+				replace(st.getObject()),
+				(Resource) replace(st.getContext())));
+	}
+
+	@Override
+	public void handleNamespace(String prefix, String uri) throws RDFHandlerException {
+		if (uri.startsWith(uriPrefix)) {
+			uri = uri.replace(uriPrefix, normUri);
+		}
+		nestedHandler.handleNamespace(prefix, uri);
+	}
+
+	private Value replace(Value v) {
+		if (v instanceof URI && v.stringValue().startsWith(uriPrefix)) {
+			return new URIImpl(v.stringValue().replace(uriPrefix, normUri));
+		} else {
+			return v;
+		}
+	}
+
+	@Override
+	public void startRDF() throws RDFHandlerException {
+		nestedHandler.startRDF();
+	}
+
+	@Override
+	public void endRDF() throws RDFHandlerException {
+		nestedHandler.endRDF();
+	}
+
+	@Override
+	public void handleComment(String comment) throws RDFHandlerException {
+		nestedHandler.handleComment(comment);
+	}
+
+}