Merge branch '1-project-creation' into 'master'

Resolve "Parser UNL"

Closes #1, #4, and #3

See merge request unl/unl2rdf!2

.gitignore

+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+
+# From : https://gist.github.com/edesdan/6bb43343740bcd54ef0f56a384a2f66f
+# Folder view configuration files
+.DS_Store
+Desktop.ini
+
+# Thumbnail cache files
+._*
+Thumbs.db
+
+# Files that might appear on external disks
+.Spotlight-V100
+.Trashes
+
+# Mac
+.DS_Store
+
+# From : https://github.com/github/gitignore/blob/master/Java.gitignore
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+
+# From : https://github.com/github/gitignore/blob/master/Maven.gitignore
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+# https://github.com/takari/maven-wrapper#usage-without-binary-jar
+.mvn/wrapper/maven-wrapper.jar

.idea/.gitignore

+# Default ignored files
+/shelf/
+/workspace.xml
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
+# Editor-based HTTP Client requests
+/httpRequests/

.idea/artifacts/unl2rdf_jar.xml

+<component name="ArtifactManager">
+  <artifact type="jar" name="unl2rdf:jar">
+    <output-path>$PROJECT_DIR$/out/artifacts/unl2rdf_jar</output-path>
+    <root id="archive" name="unl2rdf.jar">
+      <element id="module-output" name="unl2rdf" />
+      <element id="extracted-dir" path="$MAVEN_REPOSITORY$/info/picocli/picocli/4.2.0/picocli-4.2.0.jar" path-in-jar="/" />
+    </root>
+  </artifact>
+</component>
\ No newline at end of file

.idea/compiler.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="rdf" />
+        <module name="unl-parser" />
+      </profile>
+      <profile name="Annotation profile for unl2rdf" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <option name="project" value="unl2rdf/unl2rdf-app" />
+        <processorPath useClasspath="false">
+          <entry name="$MAVEN_REPOSITORY$/info/picocli/picocli-codegen/4.2.0/picocli-codegen-4.2.0.jar" />
+          <entry name="$MAVEN_REPOSITORY$/info/picocli/picocli/4.2.0/picocli-4.2.0.jar" />
+        </processorPath>
+        <module name="unl2rdf-app" />
+      </profile>
+    </annotationProcessing>
+    <bytecodeTargetLevel target="11">
+      <module name="rdf" target="11" />
+      <module name="unl-parser" target="11" />
+      <module name="unl2rdf" target="11" />
+      <module name="unl2rdf-app" target="11" />
+    </bytecodeTargetLevel>
+  </component>
+  <component name="JavacSettings">
+    <option name="ADDITIONAL_OPTIONS_OVERRIDE">
+      <module name="unl-parser" options="" />
+      <module name="unl2rdf" options="-Aproject=unl2rdf/unl2rdf" />
+      <module name="unl2rdf-app" options="-Aproject=unl2rdf/unl2rdf-app" />
+    </option>
+  </component>
+</project>
\ No newline at end of file

.idea/encodings.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/rdf/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/rdf/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/unl-parser/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/unl2rdf-app/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/unl2rdf-app/src/main/resources" charset="UTF-8" />
+  </component>
+</project>
\ No newline at end of file

.idea/jarRepositories.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>
\ No newline at end of file

.idea/misc.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+        <option value="$PROJECT_DIR$/../rdf/pom.xml" />
+      </list>
+    </option>
+    <option name="ignoredFiles">
+      <set>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </set>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_13" default="false" project-jdk-name="11" project-jdk-type="JavaSDK" />
+</project>
\ No newline at end of file

.idea/modules.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/rdf/rdf.iml" filepath="$PROJECT_DIR$/rdf/rdf.iml" />
+      <module fileurl="file://$PROJECT_DIR$/unl-parser/unl-parser.iml" filepath="$PROJECT_DIR$/unl-parser/unl-parser.iml" />
+      <module fileurl="file://$PROJECT_DIR$/unl2rdf-app/unl2rdf-app.iml" filepath="$PROJECT_DIR$/unl2rdf-app/unl2rdf-app.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file

.idea/unl2rdf.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file

.idea/vcs.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>unl2rdf</groupId>
+    <artifactId>unl2rdf</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>unl-parser</module>
+        <module>unl2rdf-app</module>
+        <module>rdf</module>
+    </modules>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-clean-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>11</source>
+                    <target>11</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-deploy-plugin</artifactId>
+                <version>3.0.0-M1</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.2.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <mainClass>unl2rdf.Unl2Rdf</mainClass>
+                            <classpathPrefix>dependency-jars/</classpathPrefix>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-resources-plugin</artifactId>
+                <version>3.1.0</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-site-plugin</artifactId>
+                <version>3.9.0</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.0.0-M4</version>
+                <configuration>
+                    <groups>acceptance | !feature-a</groups>
+                    <excludedGroups>integration, regression</excludedGroups>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <version>3.1.2</version>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.3.0</version>
+            </plugin>
+        </plugins>
+    </build>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.7.0-M1</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+
+</project>

rdf/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>unl2rdf</artifactId>
+        <groupId>unl2rdf</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>rdf</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.jena</groupId>
+            <artifactId>apache-jena-libs</artifactId>
+            <type>pom</type>
+            <version>3.14.0</version>
+        </dependency>
+    </dependencies>
+
+</project>
\ No newline at end of file

rdf/rdf.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_11">
+    <output url="file://$MODULE_DIR$/target/classes" />
+    <output-test url="file://$MODULE_DIR$/target/test-classes" />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-shacl:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-arq:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-core:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-iri:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: commons-cli:commons-cli:1.4" level="project" />
+    <orderEntry type="library" name="Maven: commons-codec:commons-codec:1.13" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-base:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.commons:commons-csv:1.7" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.commons:commons-compress:1.19" level="project" />
+    <orderEntry type="library" name="Maven: com.github.andrewoma.dexx:collection:0.7" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-shaded-guava:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.httpcomponents:httpclient:4.5.10" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.httpcomponents:httpcore:4.4.12" level="project" />
+    <orderEntry type="library" name="Maven: com.github.jsonld-java:jsonld-java:0.12.5" level="project" />
+    <orderEntry type="library" name="Maven: commons-io:commons-io:2.6" level="project" />
+    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-core:2.10.1" level="project" />
+    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-databind:2.10.1" level="project" />
+    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-annotations:2.10.1" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.httpcomponents:httpclient-cache:4.5.10" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.thrift:libthrift:0.13.0" level="project" />
+    <orderEntry type="library" name="Maven: javax.annotation:javax.annotation-api:1.3.2" level="project" />
+    <orderEntry type="library" name="Maven: org.slf4j:jcl-over-slf4j:1.7.26" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.commons:commons-lang3:3.9" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-tdb:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-tdb2:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-dboe-storage:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-dboe-trans-data:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-dboe-transaction:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-dboe-base:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-dboe-index:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.apache.jena:jena-rdfconnection:3.14.0" level="project" />
+    <orderEntry type="library" name="Maven: org.slf4j:slf4j-api:1.7.26" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter:5.7.0-M1" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-api:5.7.0-M1" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.apiguardian:apiguardian-api:1.1.0" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.opentest4j:opentest4j:1.2.0" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.platform:junit-platform-commons:1.7.0-M1" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-params:5.7.0-M1" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-engine:5.7.0-M1" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.junit.platform:junit-platform-engine:1.7.0-M1" level="project" />
+  </component>
+</module>
\ No newline at end of file

rdf/src/main/java/UnlDocumentToRdfConverter.java

+public class UnlDocumentToRdfConverter {
+}

rdf/src/test/java/RdfSchemaOfUnlTest.java

+import org.apache.jena.rdf.model.ModelFactory;
+import org.apache.jena.rdf.model.Resource;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.io.Writer;
+
+class RdfSchemaOfUnlTest {
+
+    @Test
+    void createRdfOfUnlSentence() throws IOException {
+        var model = ModelFactory.createDefaultModel();
+
+        var test = model.createResource();
+        Resource sentence = model.createResource("R2", VocabularyUnl.UNL_Sentence);
+        //sentence.addProperty(VocabularyUnl., "The system allows a radio channel to take on two states: Listening and Traffic");
+        //sentence.addProperty(VocabularyUnl.)
+        Writer writer = new StringWriter();
+        model.write(writer, "N-TRIPLES");
+        Assertions.assertFalse(writer.toString().isBlank());
+        writer.close();
+
+    }
+
+    void createUnlDocument(){
+        var unlDocument = VocabularyUnl.UNL_Sentence;
+        //unlDocument.addLabel();
+    }
+}
\ No newline at end of file

unl-parser/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>unl2rdf</groupId>
+        <version>1.0-SNAPSHOT</version>
+        <artifactId>unl2rdf</artifactId>
+    </parent>
+
+    <artifactId>unl-parser</artifactId>
+    <packaging>jar</packaging>
+
+    <name>Unl-parser</name>
+</project>

unl-parser/src/main/java/unl/EqualsBuilder.java

+package unl;
+
+import java.util.Vector;
+
+class EqualsBuilder {
+    private final Vector<Object> elements;
+
+    public EqualsBuilder() {
+        this.elements = new Vector<>();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if(null == obj) return false;
+
+        if(!(obj instanceof EqualsBuilder)) return false;
+
+        return this.isEqual((EqualsBuilder) obj);
+    }
+
+    public boolean isEqual(EqualsBuilder other) {
+        return elements.equals(other.elements);
+    }
+
+    @Override
+    public int hashCode() {
+        return new HashCodeBuilder()
+                .append(elements)
+                .toHashCode();
+    }
+
+    public <TType> EqualsBuilder append(TType v) {
+        this.elements.add(v);
+        return this;
+    }
+}

unl-parser/src/main/java/unl/Graph.java

+package unl;
+
+import java.util.Collection;
+import java.util.Vector;
+
+public class Graph {
+    private final Vector<GraphNode> nodes;
+    private final Vector<GraphRelation> relations;
+    private int nodeCounter;
+
+    public Graph(){
+        this(new Vector<>(), new Vector<>());
+    }
+
+    public Graph(Collection<GraphNode> nodes, Collection<GraphRelation> relations) {
+        this(new Vector<>(nodes), new Vector<>(relations));
+    }
+
+    private Graph(Vector<GraphNode> nodes, Vector<GraphRelation> relations) {
+        this.nodes = nodes;
+        this.relations = relations;
+        this.nodeCounter = 0;
+    }
+
+    public static GraphNode getEntryNode(GraphRelation relation, String graphNumber) {
+        String str = relation.getSubGraphReferenceLabel();
+        GraphNode graphNode = null;
+
+        if(str.equals(graphNumber)) {
+            if (relation.getNode1().isEntryNode()) graphNode = relation.getNode1();
+            if (relation.getNode2().isEntryNode()) graphNode = relation.getNode2();
+        }
+
+        return graphNode;
+    }
+
+    public static GraphNode getEntryNode(GraphRelation relation){
+        return getEntryNode(relation, "");
+    }
+
+    public Vector<GraphNode> getNodes() {
+        return nodes;
+    }
+
+    public Vector<GraphRelation> getRelations() {
+        return relations;
+    }
+
+    public void add(GraphRelation relation){
+
+        // Update node 1
+        int i1 = nodes.indexOf(relation.getNode1());
+        if (-1 == i1){
+            this.add(relation.getNode1());
+            relation.getNode1().setNodeNumber(++nodeCounter);
+        } else {
+            relation.setNode1(nodes.get(i1));
+        }
+
+        // update node 2
+        int i2 = nodes.indexOf(relation.getNode2());
+        if (-1 == i2){
+            this.add(relation.getNode2());
+            relation.getNode2().setNodeNumber(++nodeCounter);
+        } else {
+            relation.setNode2(nodes.get(i2));
+        }
+
+        relations.add(relation);
+    }
+
+    public void add(GraphNode node){
+        this.nodes.add(node);
+    }
+
+    public GraphNode getEntryNode() throws NoEntryNodeException  {
+        return getEntryNode("");
+    }
+
+    public GraphNode getEntryNode(String graphNumber) throws NoEntryNodeException {
+        int i = 0;
+        GraphNode graphNode = null;
+
+        while((i < relations.size()) && (null == graphNode)){
+            graphNode = getEntryNode(this.relations.get(i), graphNumber);
+            i++;
+        }
+
+        // we may not have found it, because the entry node is isolated (no relation...)
+        if ((null == graphNode) && (1 == this.nodes.size()) && (this.nodes.get(0).isEntryNode())){
+            graphNode = this.nodes.get(0);
+        }
+
+        if (null == graphNode) {
+            throw new NoEntryNodeException("No Entry node for subgraph " + graphNumber);
+        }
+        return graphNode;
+
+    }
+
+    @Override
+    public java.lang.String toString() {
+        return InternalToString();
+    }
+
+    protected String InternalToString(){
+        StringBuilder sb = new StringBuilder();
+
+        if(this.relations.isEmpty() && !this.nodes.isEmpty()){
+            sb.append("[W]")
+                    .append(this.convertNodesToString())
+                    .append("[/W]");
+        } else {
+            sb.append(this.convertRelationsToString());
+        }
+
+        return sb.toString();
+    }
+
+    private String convertRelationsToString() {
+        StringBuilder strBuilder = new StringBuilder();
+
+        for (GraphRelation graphRelation : this.relations) {
+            strBuilder.append(graphRelation.toString())
+                    .append("\n");
+        }
+
+        return strBuilder.toString();
+    }
+
+    private java.lang.String convertNodesToString() {
+        StringBuilder strBuilder = new StringBuilder();
+
+        for (GraphNode graphNode :
+                this.nodes) {
+            strBuilder.append(graphNode.toString())
+            .append("\n");
+        }
+
+        return strBuilder.toString();
+    }
+
+}