uloimport: add Importer

src/uloimport/src/main/java/info/kwarc/uloimport/ImportException.java

+package info.kwarc.uloimport;
+
+/**
+ * An Exception caused by an import of ULO/RDF data.
+ */
+public class ImportException extends RuntimeException {
+    /**
+     * Construct a new {@link ImportException} with just a message.
+     *
+     * @param message The message associated with this exception.
+     */
+    public ImportException(String message) {
+        super(message);
+    }
+
+    /**
+     * Construct a new {@link ImportException} with a message and a cause
+     * that caused this exception.
+     *
+     * @param message The message associated with this exception.
+     * @param cause The underlying cause of the import error.
+     */
+    public ImportException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/uloimport/src/main/java/info/kwarc/uloimport/Importer.java

+package info.kwarc.uloimport;
+
+import java.io.InputStream;
+
+public interface Importer {
+    /**
+     * Import the (single) ULO/RDF file at the given input stream to the
+     * storage underlying this {@link Importer}.
+     *
+     * @param is The stream from which to read a single ULO/RDF file.
+     * @throws ImportException When the import failed.
+     */
+    void importUlo(InputStream is) throws ImportException;
+}