GH-287: Add JSON support for serializing and deserializing AASX files

dataformat-aasx/pom.xml

@@ -16,6 +16,10 @@
             <groupId>${project.groupId}</groupId>
             <artifactId>aas4j-dataformat-xml</artifactId>
         </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>aas4j-dataformat-json</artifactId>
+        </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>aas4j-dataformat-core</artifactId>

dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXDeserializer.java

@@ -33,6 +33,7 @@
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.internal.AASXUtils;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.DeserializationException;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.internal.visitor.AssetAdministrationShellElementWalkerVisitor;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonDeserializer;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.xml.XmlDeserializer;
 import org.eclipse.digitaltwin.aas4j.v3.model.Environment;
 import org.eclipse.digitaltwin.aas4j.v3.model.File;
@@ -52,7 +53,8 @@ public class AASXDeserializer {
     private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
 
 
-    private final XmlDeserializer deserializer;
+    private final XmlDeserializer xmlDeserializer;
+    private final JsonDeserializer jsonDeserializer;
 
     private Environment environment;
     private final OPCPackage aasxRoot;
@@ -66,20 +68,40 @@ public class AASXDeserializer {
      */
     public AASXDeserializer(InputStream inputStream) throws InvalidFormatException, IOException {
         aasxRoot = OPCPackage.open(inputStream);
-        this.deserializer = new XmlDeserializer();
+        this.xmlDeserializer = new XmlDeserializer();
+        this.jsonDeserializer = new JsonDeserializer();
     }
 
     /**
-     * Constructor for custom XML deserialization
-     * 
-     * @param deserializer a custom deserializer used for deserializing the aas environment
+     * Constructor for custom deserialization
+     *
+     * @param xmlDeserializer a custom XML deserializer used for deserializing the aas environment
+     * @param inputStream an input stream to an aasx package that can be read with this instance
+     * @throws InvalidFormatException if aasx package format is invalid
+     * @throws IOException if creating input streams for aasx fails
+     */
+    public AASXDeserializer(XmlDeserializer xmlDeserializer,
+                            InputStream inputStream) throws InvalidFormatException, IOException {
+        aasxRoot = OPCPackage.open(inputStream);
+        this.xmlDeserializer = xmlDeserializer;
+        this.jsonDeserializer = new JsonDeserializer();
+    }
+
+    /**
+     * Constructor for custom deserialization
+     *
+     * @param xmlDeserializer a custom XML deserializer used for deserializing the aas environment
+     * @param jsonDeserializer a custom JSON deserializer used for deserializing the aas environment
      * @param inputStream an input stream to an aasx package that can be read with this instance
      * @throws InvalidFormatException if aasx package format is invalid
      * @throws IOException if creating input streams for aasx fails
      */
-    public AASXDeserializer(XmlDeserializer deserializer, InputStream inputStream) throws InvalidFormatException, IOException {
+    public AASXDeserializer(XmlDeserializer xmlDeserializer,
+                            JsonDeserializer jsonDeserializer,
+                            InputStream inputStream) throws InvalidFormatException, IOException {
         aasxRoot = OPCPackage.open(inputStream);
-        this.deserializer = deserializer;
+        this.xmlDeserializer = xmlDeserializer;
+        this.jsonDeserializer = jsonDeserializer;
     }
 
     /**
@@ -96,18 +118,61 @@ public Environment read() throws InvalidFormatException, IOException, Deserializ
         if (environment != null) {
             return environment;
         }
-        environment = deserializer.read(getXMLResourceString(aasxRoot));
+        if (MetamodelContentType.XML.equals(getContentType())) {
+            environment = xmlDeserializer.read(getResourceString(aasxRoot));
+        }
+        if (MetamodelContentType.JSON.equals(getContentType())) {
+            environment = jsonDeserializer.read(getResourceString(aasxRoot), Environment.class);
+        }
         return environment;
     }
 
+    /**
+     * Currently XML and JSON are supported for deserializing.
+     * @return The content type of the metafile
+     * @throws InvalidFormatException if aasx package format is invalid
+     * @throws IOException if creating input streams for aasx fails
+     */
+    protected MetamodelContentType getContentType()  throws InvalidFormatException, IOException {
+        MetamodelContentType contentType;
+        PackagePart packagePart = getPackagePart(aasxRoot);
+        // We also check for the none official content types "test/xml" and "text/json", which are commonly used
+        switch (packagePart.getContentType()) {
+            case "text/xml":
+            case "application/xml":
+                contentType = MetamodelContentType.XML;
+                break;
+            case "text/json":
+            case "application/json":
+                contentType = MetamodelContentType.JSON;
+                break;
+            default:
+                throw new RuntimeException("The following content type is not supported: " + packagePart.getContentType());
+        }
+        return contentType;
+    }
+
     /**
      * Return the Content of the xml file in the aasx-package as String
-     * 
+     *
+     * @deprecated This method will be replaced by the method {@link AASXDeserializer#getResourceString()}.
+     *
      * @throws InvalidFormatException if aasx package format is invalid
      * @throws IOException if creating input streams for aasx fails
      */
+    @Deprecated
     public String getXMLResourceString() throws InvalidFormatException, IOException {
-        return getXMLResourceString(this.aasxRoot);
+        return getResourceString(this.aasxRoot);
+    }
+
+    /**
+     * Return the Content of the xml or json file in the aasx-package as String
+     *
+     * @throws InvalidFormatException if aasx package format is invalid
+     * @throws IOException if creating input streams for aasx fails
+     */
+    public String getResourceString() throws InvalidFormatException, IOException {
+        return getResourceString(this.aasxRoot);
     }
 
     /**
@@ -134,13 +199,14 @@ public List<InMemoryFile> getRelatedFiles() throws InvalidFormatException, IOExc
         return files;
     }
 
-    private String getXMLResourceString(OPCPackage aasxPackage) throws InvalidFormatException, IOException {
+    private PackagePart getPackagePart(OPCPackage aasxPackage) throws InvalidFormatException, IOException {
         PackagePart originPart = getOriginPart(aasxPackage);
-
         PackageRelationshipCollection originRelationships = getXMLDocumentRelation(originPart);
+        return originPart.getRelatedPart(originRelationships.getRelationship(0));
+    }
 
-        PackagePart xmlPart = originPart.getRelatedPart(originRelationships.getRelationship(0));
-
+    private String getResourceString(OPCPackage aasxPackage) throws InvalidFormatException, IOException {
+        PackagePart xmlPart = getPackagePart(aasxPackage);
         return readContentFromPackagePart(xmlPart);
     }
 

dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXSerializer.java

@@ -34,6 +34,7 @@
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.internal.AASXUtils;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.SerializationException;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.internal.visitor.AssetAdministrationShellElementWalkerVisitor;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonSerializer;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.xml.XmlSerializer;
 import org.eclipse.digitaltwin.aas4j.v3.model.Environment;
 import org.eclipse.digitaltwin.aas4j.v3.model.File;
@@ -49,6 +50,7 @@ public class AASXSerializer {
 
     private static final String MIME_PLAINTXT = "text/plain";
     private static final String MIME_XML = "application/xml";
+    private static final String MIME_JSON = "application/json";
 
     public static final String OPC_NAMESPACE = "http://schemas.openxmlformats.org/package/2006/relationships";
     public static final String AASX_NAMESPACE = "http://admin-shell.io/aasx/relationships";
@@ -59,6 +61,7 @@ public class AASXSerializer {
 
     public static final String AASSPEC_RELTYPE = AASX_NAMESPACE + "/aas-spec";
     public static final String XML_PATH = "/aasx/xml/content.xml";
+    public static final String JSON_PATH = "/aasx/json/content.json";
 
     public static final String AASSUPPL_RELTYPE = AASX_NAMESPACE + "/aas-suppl";
 
@@ -67,25 +70,39 @@ public class AASXSerializer {
     private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
 
     private final XmlSerializer xmlSerializer;
+    private final JsonSerializer jsonSerializer;
 
     /**
      * Default constructor
      */
     public AASXSerializer() {
         this.xmlSerializer = new XmlSerializer();
+        this.jsonSerializer = new JsonSerializer();
     }
 
     /**
-     * Constructor with a custom serializer for serializing the aas environment
+     * Constructor with a custom XML serializer for serializing the aas environment
      *
-     * @param xmlSerializer a custom serializer used for serializing the aas environment
+     * @param xmlSerializer a custom serializer used for serializing the aas environment in XML
      */
     public AASXSerializer(XmlSerializer xmlSerializer) {
         this.xmlSerializer = xmlSerializer;
+        this.jsonSerializer = new JsonSerializer();
     }
 
     /**
-     * Generates the .aasx file and writes it to the given OutputStream
+     * Constructor with custom serializers for serializing the aas environment
+     *
+     * @param xmlSerializer a custom serializer used for serializing the aas environment in XML
+     * @param jsonSerializer a custom serializer used for serializing the aas environment in JSON
+     */
+    public AASXSerializer(XmlSerializer xmlSerializer, JsonSerializer jsonSerializer) {
+        this.xmlSerializer = xmlSerializer;
+        this.jsonSerializer = jsonSerializer;
+    }
+
+    /**
+     * Generates the .aasx file and writes it to the given OutputStream, by using XML as the default content type.
      *
      * @param environment the aas environment that will be included in the aasx package as an xml serialization
      * @param files related inMemory files that belong to the given aas environment
@@ -96,25 +113,53 @@ public AASXSerializer(XmlSerializer xmlSerializer) {
     public void write(Environment environment, Collection<InMemoryFile> files, OutputStream os)
             throws SerializationException, IOException {
 
+        write(environment, files, os, MetamodelContentType.XML);
+    }
+
+    /**
+     * Generates the .aasx file and writes it to the given OutputStream
+     *
+     * @param environment the aas environment that will be included in the aasx package as an xml serialization
+     * @param files related inMemory files that belong to the given aas environment
+     * @param os an output stream for writing the aasx package
+     * @param contentType the content type for the metamodel serialization
+     * @throws SerializationException if serializing the given elements fails
+     * @throws IOException if creating output streams for aasx fails
+     */
+    public void write(Environment environment, Collection<InMemoryFile> files, OutputStream os, MetamodelContentType contentType)
+            throws SerializationException, IOException {
+
         OPCPackage rootPackage = OPCPackage.create(os);
 
         // Create the empty aasx-origin file
         PackagePart origin = createAASXPart(rootPackage, rootPackage, ORIGIN_PATH, MIME_PLAINTXT, ORIGIN_RELTYPE,
                 ORIGIN_CONTENT.getBytes());
 
-        // Convert the given Metamodels to XML
-        String xml = xmlSerializer.write(environment);
-
-        // Save the XML to aasx/xml/content.xml
-        PackagePart xmlPart = createAASXPart(rootPackage, origin, XML_PATH, MIME_XML, AASSPEC_RELTYPE, xml.getBytes(DEFAULT_CHARSET));
+        PackagePart packagePart;
+        switch (contentType) {
+            case JSON:
+                // Convert the given Metamodels to JSON
+                String json = jsonSerializer.write(environment);
+                // Save the JSON to aasx/json/content.json
+                packagePart = createAASXPart(rootPackage, origin, JSON_PATH, MIME_JSON, AASSPEC_RELTYPE, json.getBytes(DEFAULT_CHARSET));
+                break;
+            case XML:
+                // Convert the given Metamodels to XML
+                String xml = xmlSerializer.write(environment);
+                // Save the XML to aasx/xml/content.xml
+                packagePart = createAASXPart(rootPackage, origin, XML_PATH, MIME_XML, AASSPEC_RELTYPE, xml.getBytes(DEFAULT_CHARSET));
+                break;
+            default:
+                throw new IllegalArgumentException("Unsupported content type: " + contentType);
+        }
 
         environment.getAssetAdministrationShells().stream().filter(aas -> aas.getAssetInformation() != null
-                         && aas.getAssetInformation().getDefaultThumbnail() != null
-                         && aas.getAssetInformation().getDefaultThumbnail().getPath() != null)
-                   .forEach(aas -> createParts(files,
-                         AASXUtils.removeFilePartOfURI(aas.getAssetInformation().getDefaultThumbnail().getPath()),
-                         rootPackage, rootPackage, aas.getAssetInformation().getDefaultThumbnail().getContentType(), AAS_THUMBNAIL_RELTYPE));
-        storeFilesInAASX(environment, files, rootPackage, xmlPart);
+                        && aas.getAssetInformation().getDefaultThumbnail() != null
+                        && aas.getAssetInformation().getDefaultThumbnail().getPath() != null)
+                .forEach(aas -> createParts(files,
+                        AASXUtils.removeFilePartOfURI(aas.getAssetInformation().getDefaultThumbnail().getPath()),
+                        rootPackage, rootPackage, aas.getAssetInformation().getDefaultThumbnail().getContentType(), AAS_THUMBNAIL_RELTYPE));
+        storeFilesInAASX(environment, files, rootPackage, packagePart);
 
         saveAASX(os, rootPackage);
     }

dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXValidator.java

@@ -16,6 +16,8 @@
 package org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx;
 
 import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.DeserializationException;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.json.JsonSchemaValidator;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.xml.XmlSchemaValidator;
 import org.xml.sax.SAXException;
 
@@ -29,10 +31,12 @@
 public class AASXValidator {
 
     private XmlSchemaValidator xmlValidator;
+    private JsonSchemaValidator jsonValidator;
     private AASXDeserializer deserializer;
 
     public AASXValidator(InputStream is) throws SAXException, IOException, InvalidFormatException {
         this.xmlValidator = new XmlSchemaValidator();
+        this.jsonValidator = new JsonSchemaValidator();
         this.deserializer = new AASXDeserializer(is);
     }
 
@@ -44,8 +48,15 @@ public AASXValidator(InputStream is) throws SAXException, IOException, InvalidFo
      * @throws InvalidFormatException specified URI is invalid
      */
     public Set<String> validateSchema() throws IOException, InvalidFormatException {
-        String file = deserializer.getXMLResourceString();
-        return xmlValidator.validateSchema(file);
+        String file = deserializer.getResourceString();
+        Set<String> errorMessages = null;
+        if (MetamodelContentType.XML.equals(deserializer.getContentType())) {
+            errorMessages = xmlValidator.validateSchema(file);
+        }
+        else if (MetamodelContentType.JSON.equals(deserializer.getContentType())) {
+            errorMessages = jsonValidator.validateSchema(file);
+        }
+        return errorMessages;
     }
 
 }

dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/MetamodelContentType.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * 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 org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx;
+
+/**
+ * Supported ContentType's for serializing and deserializing Metamodels.
+ */
+public enum MetamodelContentType {
+
+    JSON,
+    XML
+
+}

dataformat-aasx/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/deserialization/AASXDeserializerTest.java

@@ -34,6 +34,7 @@
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.AASXDeserializer;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.AASXSerializer;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.InMemoryFile;
+import org.eclipse.digitaltwin.aas4j.v3.dataformat.aasx.MetamodelContentType;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.AASSimple;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.DeserializationException;
 import org.eclipse.digitaltwin.aas4j.v3.dataformat.core.SerializationException;
@@ -65,17 +66,26 @@ public void roundTrip() throws SerializationException, IOException, InvalidForma
         fileList.add(inMemoryFile);
         fileList.add(inMemoryFileThumbnail);
 
-        java.io.File file = tempFolder.newFile("output.aasx");
-
+        // check round trip with XML content
+        java.io.File file = tempFolder.newFile("output-xml.aasx");
         new AASXSerializer().write(AASSimple.createEnvironment(), fileList, new FileOutputStream(file));
 
         InputStream in = new FileInputStream(file);
         AASXDeserializer deserializer = new AASXDeserializer(in);
 
         assertEquals(AASSimple.createEnvironment(), deserializer.read());
         assertTrue(CollectionUtils.isEqualCollection(fileList, deserializer.getRelatedFiles()));
-    }
 
+        // check round trip with JSON content
+        file = tempFolder.newFile("output-json.aasx");
+        new AASXSerializer().write(AASSimple.createEnvironment(), fileList, new FileOutputStream(file), MetamodelContentType.JSON);
+
+        in = new FileInputStream(file);
+        deserializer = new AASXDeserializer(in);
+
+        assertEquals(AASSimple.createEnvironment(), deserializer.read());
+        assertTrue(CollectionUtils.isEqualCollection(fileList, deserializer.getRelatedFiles()));
+    }
     @Test
     public void relatedFilesAreOnlyResolvedIfWithinAASX() throws IOException, SerializationException, InvalidFormatException, DeserializationException {
         Submodel fileSm = new DefaultSubmodel.Builder().id("doesNotMatter").submodelElements(createFileSubmodelElements()).build();