feat(bpmn): improve namespace prefixes in bpmn generated file (#50)

Use explicit namespace prefixes instead of default ns1, ns2, ...
Notice that there is no more default namespace, BPMN model schema is mapped to the semantic prefix.

In addition, we now generated formatted/pretty-print xml.

java/pom.xml

@@ -12,7 +12,6 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
 
-        <jaxb.version>2.3.1</jaxb.version>
         <junit.version>5.6.2</junit.version>
         <log4j.version>2.13.2</log4j.version>
     </properties>
@@ -25,16 +24,16 @@
             <scope>provided</scope>
         </dependency>
         <dependency>
-            <groupId>javax.xml.bind</groupId>
-            <artifactId>jaxb-api</artifactId>
-            <version>${jaxb.version}</version>
+            <groupId>jakarta.xml.bind</groupId>
+            <artifactId>jakarta.xml.bind-api</artifactId>
+            <version>2.3.3</version>
         </dependency>
         <dependency>
-            <groupId>org.glassfish.jaxb</groupId>
-            <artifactId>jaxb-runtime</artifactId>
-            <version>${jaxb.version}</version>
-            <scope>runtime</scope>
+            <groupId>com.sun.xml.bind</groupId>
+            <artifactId>jaxb-impl</artifactId>
+            <version>2.3.3</version>
         </dependency>
+
         <!-- to be bundled only with the application not the library -->
         <dependency>
             <groupId>org.apache.logging.log4j</groupId>

java/src/main/java/io/process/analytics/tools/bpmn/generator/internal/BpmnNamespacePrefixMapper.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 Bonitasoft S.A.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.process.analytics.tools.bpmn.generator.internal;
+
+import com.sun.xml.bind.marshaller.NamespacePrefixMapper;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class BpmnNamespacePrefixMapper extends NamespacePrefixMapper {
+
+    private static final Map<String, String> namespaces = new HashMap<>();
+    static {
+        namespaces.put("http://www.omg.org/spec/BPMN/20100524/DI", "bpmndi");
+        namespaces.put("http://www.omg.org/spec/BPMN/20100524/MODEL", "semantic");
+        namespaces.put("http://www.omg.org/spec/DD/20100524/DC", "dc");
+        namespaces.put("http://www.omg.org/spec/DD/20100524/DI", "di");
+    }
+
+    @Override
+    public String getPreferredPrefix(String namespaceUri, String suggestion, boolean requirePrefix) {
+        return namespaces.getOrDefault(namespaceUri, suggestion);
+    }
+
+    @Override
+    public String[] getPreDeclaredNamespaceUris() {
+        Set<String> uris = namespaces.keySet();
+        return uris.toArray(new String[0]);
+    }
+
+}

java/src/main/java/io/process/analytics/tools/bpmn/generator/internal/XmlParser.java

@@ -18,15 +18,14 @@
 import java.io.File;
 import java.io.StringReader;
 
-import javax.xml.bind.JAXBContext;
-import javax.xml.bind.JAXBElement;
-import javax.xml.bind.JAXBException;
+import javax.xml.bind.*;
 import javax.xml.transform.stream.StreamSource;
 
 import io.process.analytics.tools.bpmn.generator.internal.generated.model.ObjectFactory;
 import io.process.analytics.tools.bpmn.generator.internal.generated.model.TDefinitions;
 
 public class XmlParser {
+
     private static final JAXBContext context = initContext();
 
     private static JAXBContext initContext() {
@@ -40,12 +39,25 @@ private static JAXBContext initContext() {
     public void marshal(TDefinitions definitions, File outputFile) {
         try {
             JAXBElement<TDefinitions> root = new ObjectFactory().createDefinitions(definitions);
-            context.createMarshaller().marshal(root, outputFile);
+            createMarshaller().marshal(root, outputFile);
         } catch (JAXBException e) {
             throw new RuntimeException("Unable to marshal", e);
         }
     }
 
+    private Marshaller createMarshaller() throws JAXBException {
+        Marshaller marshaller = context.createMarshaller();
+        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
+        try {
+            marshaller.setProperty("com.sun.xml.bind.namespacePrefixMapper", new BpmnNamespacePrefixMapper());
+        } catch(PropertyException e) {
+            // In case another JAXB implementation is used
+            // do not stop processing, namespace prefixes will be generated automatically in that case
+            e.printStackTrace();
+        }
+        return marshaller;
+    }
+
     public TDefinitions unmarshall(String xml) {
         try {
             StreamSource source = new StreamSource(new StringReader(xml));

java/src/test/java/io/process/analytics/tools/bpmn/generator/AppTest.java

@@ -46,7 +46,7 @@ public void main_generates_xml_output_file() throws Exception {
 
         File bpmnFile = new File(outputPath);
         assertThat(bpmnFile).exists().isFile();
-        assertThat(fileContent(bpmnFile)).contains("<definitions xmlns=\"http://www.omg.org/spec/BPMN/20100524/MODEL\"");
+        assertThat(fileContent(bpmnFile)).contains("<semantic:definitions xmlns:semantic=\"http://www.omg.org/spec/BPMN/20100524/MODEL\"");
     }
 
     @Test