Add VrpXMLWrite method that returns OutputStream

Add test to check that two outputs are the same

jsprit-io/src/main/java/com/graphhopper/jsprit/io/problem/VrpXMLWriter.java

@@ -41,9 +41,7 @@ import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 
-import java.io.FileWriter;
+import java.io.*;
-import java.io.IOException;
-import java.io.Writer;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -94,8 +92,36 @@ public class VrpXMLWriter {
     public void write(String filename) {
         if (!filename.endsWith(".xml")) filename += ".xml";
         log.info("write vrp: " + filename);
+        XMLConf xmlConfig = createXMLConfiguration();
+
+        try {
+            xmlConfig.setFileName(filename);
+            Writer out = new FileWriter(filename);
+            XMLSerializer serializer = new XMLSerializer(out, createOutputFormat());
+            serializer.serialize(xmlConfig.getDocument());
+            out.close();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public OutputStream write() {
+        XMLConf xmlConfig = createXMLConfiguration();
+        OutputStream out = new ByteArrayOutputStream();
+
+        try {
+            XMLSerializer serializer = new XMLSerializer(out, createOutputFormat());
+            serializer.serialize(xmlConfig.getDocument());
+            out.close();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+
+        return out;
+    }
+
+    private XMLConf createXMLConfiguration() {
         XMLConf xmlConfig = new XMLConf();
-        xmlConfig.setFileName(filename);
         xmlConfig.setRootElementName("problem");
         xmlConfig.setAttributeSplittingDisabled(true);
         xmlConfig.setDelimiterParsingDisabled(true);
@@ -123,10 +149,6 @@ public class VrpXMLWriter {
         writeSolutions(xmlConfig);
 
 
-        OutputFormat format = new OutputFormat();
-        format.setIndenting(true);
-        format.setIndent(5);
-
         try {
             Document document = xmlConfig.createDoc();
 
@@ -138,17 +160,14 @@ public class VrpXMLWriter {
         } catch (ConfigurationException e) {
             throw new RuntimeException(e);
         }
+        return xmlConfig;
+    }
 
-        try {
+    private OutputFormat createOutputFormat() {
-            Writer out = new FileWriter(filename);
+        OutputFormat format = new OutputFormat();
-            XMLSerializer serializer = new XMLSerializer(out, format);
+        format.setIndenting(true);
-            serializer.serialize(xmlConfig.getDocument());
+        format.setIndent(5);
-            out.close();
+        return format;
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-
-
     }
 
     private void writeInitialRoutes(XMLConf xmlConfig) {

jsprit-io/src/test/java/com/graphhopper/jsprit/io/problem/VrpXMLWriterTest.java

@@ -34,6 +34,10 @@ import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -621,6 +625,19 @@ public class VrpXMLWriterTest {
         assertEquals("2", Solutions.bestOf(solutionsToRead).getUnassignedJobs().iterator().next().getId());
     }
 
+    @Test
+    public void outputStreamAndFileContentsAreEqual() throws IOException {
+        VehicleRoutingProblem.Builder builder = twoVehicleTypesAndImpls();
+        VehicleRoutingProblem vrp = builder.build();
+
+        new VrpXMLWriter(vrp, null).write(infileName);
+        String outputStringFromFile = new String(Files.readAllBytes(Paths.get(infileName)));
+        String outputStringFromStream = new VrpXMLWriter(vrp, null).write().toString();
+
+        assertEquals(outputStringFromFile, outputStringFromStream);
+
+    }
+
     private VehicleRoutingProblem writeAndRereadXml(VehicleRoutingProblem vrp) {
         new VrpXMLWriter(vrp, null).write(infileName);