added a default export configuration

src/main/java/kieker/analysis/util/graph/export/dot/DotExporter.java

@@ -16,7 +16,7 @@ import kieker.analysis.util.graph.util.dot.attributes.DotNodeAttribute;
 public class DotExporter extends DotElementExporter {
 
 	public DotExporter(final Graph graph, final Writer writer) {
-		this(graph, writer, new DotExportConfiguration());
+		this(graph, writer, new SimpleDotExportConfiguration());
 	}
 
 	public DotExporter(final Graph graph, final Writer writer, final DotExportConfiguration configuration) {

src/main/java/kieker/analysis/util/graph/export/dot/SimpleDotExportConfiguration.java

+package kieker.analysis.util.graph.export.dot;
+
+import kieker.analysis.util.graph.Edge;
+import kieker.analysis.util.graph.Vertex;
+import kieker.analysis.util.graph.mapping.DirectPropertyMapper;
+import kieker.analysis.util.graph.util.dot.attributes.DotEdgeAttribute;
+import kieker.analysis.util.graph.util.dot.attributes.DotNodeAttribute;
+
+public class SimpleDotExportConfiguration extends DotExportConfiguration {
+
+	public SimpleDotExportConfiguration() {
+		super();
+		this.getNodeAttributes().put(DotNodeAttribute.LABEL, new DirectPropertyMapper<Vertex>("label"));
+		this.getEdgeAttributes().put(DotEdgeAttribute.LABEL, new DirectPropertyMapper<Edge>("label"));
+	}
+
+}

src/main/java/kieker/analysis/util/graph/mapping/DirectPropertyMapper.java

+package kieker.analysis.util.graph.mapping;
+
+import java.util.function.Function;
+
+import kieker.analysis.util.graph.Element;
+
+/**
+ * This function maps a graph element by a passed property key to the
+ * corresponding property value and returns it as string.
+ *
+ * @author Sören Henning
+ *
+ */
+public class DirectPropertyMapper<T extends Element> implements Function<T, String> {
+
+	private String propertyKey;
+
+	public DirectPropertyMapper(final String propertyKey) {
+		this.propertyKey = propertyKey;
+	}
+
+	public String getPropertyKey() {
+		return propertyKey;
+	}
+
+	public void setPropertyKey(final String propertyKey) {
+		this.propertyKey = propertyKey;
+	}
+
+	@Override
+	public String apply(final T element) {
+		return element.getProperty(propertyKey);
+	}
+
+}