Don't send empty matches to receiver of regexp morph function

Author: fsteeg

src/main/java/org/culturegraph/mf/morph/functions/Regexp.java

@@ -42,21 +42,29 @@ public void receive(final String name, final String value, final NamedValueSourc
 		matcher.reset(value);
 		if (null == format) {
 			while (matcher.find()) {
-				getNamedValueReceiver().receive(name, matcher.group(), source, recordCount, entityCount);
+				final String group = matcher.group();
+				if (!group.isEmpty()) {
+					getNamedValueReceiver().receive(name, group, source, recordCount, entityCount);
+				}
 			}
 		} else {
 			while (matcher.find()) {
-				getNamedValueReceiver().receive(name, matchAndFormat(), source, recordCount, entityCount);
+				if (!matchAndFormatIsEmpty()) {
+					getNamedValueReceiver().receive(name,
+							StringUtil.format(format, tempVars), source, recordCount, entityCount);
+				}
 			}
 		}
 	}
 
-	private String matchAndFormat() {
+	private boolean matchAndFormatIsEmpty() {
 		tempVars.clear();
 		for (int i = 0; i <= matcher.groupCount(); ++i) {
-			tempVars.put(String.valueOf(i), matcher.group(i));
+			if (!matcher.group(i).isEmpty()) {
+				tempVars.put(String.valueOf(i), matcher.group(i));
+			}
 		}
-		return StringUtil.format(format, tempVars);
+		return tempVars.isEmpty();
 	}
 
 	/**

src/test/java/org/culturegraph/mf/morph/functions/FunctionTest.java

@@ -24,5 +24,5 @@
  * @author Markus Michael Geipel
  */
 @RunWith(TestSuite.class)
-@TestDefinitions({"Basic.xml","Lookup.xml","Stateful.xml", "Unique.xml", "Misc.xml", "Script.xml"})
+@TestDefinitions({"Basic.xml","Lookup.xml","Stateful.xml", "Unique.xml", "Misc.xml", "Script.xml", "Regexp.xml"})
 public final class FunctionTest {/*bind to xml test*/}

src/test/java/org/culturegraph/mf/morph/functions/Regexp.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<metamorph-test version="1.0"
+	xmlns="http://www.culturegraph.org/metamorph-test" xmlns:cgxml="http://www.culturegraph.org/cgxml"
+	xmlns:mm="http://www.culturegraph.org/metamorph">
+	<test-case name="Regexp function">
+		<input type="text/x-cg+xml">
+			<cgxml:cgxml version="1.0">
+				<cgxml:records>
+					<cgxml:record id="1">
+						<cgxml:entity name="001">
+							<cgxml:literal name="" value="184000" />
+						</cgxml:entity>
+					</cgxml:record>
+				</cgxml:records>
+			</cgxml:cgxml>
+		</input>
+		<transformation type="text/x-metamorph+xml">
+			<mm:metamorph version="1">
+				<mm:rules>
+					<mm:data source="001." name="subject">
+						<mm:regexp match=".*" format="resource:P${0}" />
+					</mm:data>
+					<mm:data source="001." name="subject">
+						<mm:regexp match=".*" />
+					</mm:data>
+				</mm:rules>
+			</mm:metamorph>
+		</transformation>
+		<result type="text/x-cg+xml">
+			<cgxml:cgxml version="1.0">
+				<cgxml:records>
+					<cgxml:record id="1">
+						<cgxml:literal name="subject" value="resource:P184000" />
+						<cgxml:literal name="subject" value="184000" />
+					</cgxml:record>
+				</cgxml:records>
+			</cgxml:cgxml>
+		</result>
+	</test-case>
+</metamorph-test>