Java Tooling for Working with Aspect Models
General Considerations
In this section, the Java APIs for working with Aspect Models are described. All of the components described in the
following subsections can either be included in your project using a dedicated dependency (as described in the
respective subsection), or you can use the aspect-model-starter
artifact that aggregates all necessary dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-starter</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-starter:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-starter:2.9.7")
Getting the right version
The tooling can be made available in two different versions: release
and milestone
. The release version represents a stable version of the product
and can be referenced in your projects in the usual way from the Maven Central repository. There is also the possibility to have the intermediate builds
made available, these are called milestone
builds. Instead of Maven Central, these are released via
GitHub Packages mechanism.
To be able to use the artifacts released in this way in your projects, first the right repository has to be added to your pom.xml
file:
<repositories>
<repository>
<id>github</id>
<name>ESMF SDK</name>
<url>https://maven.pkg.github.com/eclipse-esmf/esmf-sdk</url>
<releases><enabled>true</enabled></releases>
<snapshots><enabled>true</enabled></snapshots>
</repository>
</repositories>
Then the desired dependencies can be referenced in the usual way. For an example, please refer to Github - Installing a package.
JDK requirements
The esmf-sdk components are built with Java 17 and require a JDK >= 17 such as Adoptium Temurin.
The esmf-sdk can also be used with a Java 17-compatible GraalVM JDK. With GraalVM you need to make the Graal JavaScript component available, as parts of the SDK such as the Aspect Model validation component require embedded JavaScript execution:
-
For using the esmf-sdk in the GraalVM itself, install the JS component using the GraalVM Updater:
gu install js
-
For using the esmf-sdk with GraalVM
native-image
, be sure to use the--language:js
option when building the native image; for more information see polyglot programming.
When using esmf-sdk with a GraalVM JDK and you target
|
Parsing Aspect Model URNs
The aspect-model-urn
artifact provides a way to parse and validate Aspect model element URNs as described in the
specification.
Show used imports
import org.eclipse.esmf.aspectmodel.urn.AspectModelUrn;
final AspectModelUrn urn = AspectModelUrn.fromUrn( "urn:samm:com.example:1.0.0#Example" );
final String namespace = urn.getNamespaceMainPart(); // com.example
final String name = urn.getName(); // Example
final String version = urn.getVersion(); // 1.0.0
final String urnPrefix = urn.getUrnPrefix(); // urn:samm:com.example:1.0.0#
To include the artifact, use the following dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-urn</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-urn:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-urn:2.9.7")
Loading and Saving Aspect Models
Aspect models are, like the Semantic Aspect Meta Model, described using the Resource Description Format (RDF, [rdf11]) and the Terse RDF Triple Language syntax (TTL, [turtle]). When an Aspect Model is loaded, there are two ways of working with it: Either on the abstraction level of the underlying RDF/Turtle serialization, or on the native Java Aspect Model level, where the model is represented as a Java object graph. Both approaches have different use cases and advantages and both are supported by the Aspect Model Java tooling:
Working on the RDF level | Using the Java Aspect model |
---|---|
|
|
As a rule of thumb, if your use case mostly consists of consuming Aspect models, you should prefer the Java Aspect model, if you create or edit Aspect models, or build code interfacing with other RDF vocabularies, this is better done using the RDF API.
Loading an Aspect Model to work on the Java Aspect Model Level
To load an AspectModel, you use the org.eclipse.esmf.aspectmodel.loader.AspectModelLoader
class. An instance
of AspectModelLoader
provides load()
methods to load an Aspect Model from an InputStream, one or multiple
Files, or a number of AspectModelUrn
(where you can delegate finding out where a model element is defined
to the AspectModelLoader - details on that are explained in the next section).
The AspectModelLoader
loads Aspect Models based on the most recent version of the Semantic Aspect Meta Model
and previous versions: Models based on older meta model versions are automatically translated to models
corresponding to the latest meta model version.
The resulting AspectModel
object contains information about the loaded model elements, their
namespaces and the files they were defined in. Details about the structure of these objects can be
found in the
Decision
Record 0007. The AspectModel
provides the methods elements()
, files()
and namespaces()
as
well as the convenience methods aspects()
(which returns all Aspect elements in the model) and
aspect()
, which returns the single Aspect element if one exists.
Show used imports
import java.io.File;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
import org.eclipse.esmf.metamodel.ModelElement;
final AspectModel aspectModel = new AspectModelLoader().load(
// a File, InputStream or AspectModelUrn
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" )
);
// Do something with the elements
for ( final ModelElement element : aspectModel.elements() ) {
System.out.printf( "Model element: %s has URN %s%n", element.getName(), element.urn() );
}
// Directly work with the Aspect, if the AspectModel happens to contain
// exactly one Aspect. If there are 0 or >1 Aspects, this will throw an exception.
System.out.println( "Aspect URN: " + aspectModel.aspect().urn() );
}
}
To include the Java Aspect Model artifact, use the following dependency:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-meta-model-java</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-meta-model-java:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-meta-model-java:2.9.7")
Understanding Model Resolution
The example in the last section showed how a self-contained Aspect Model file can be loaded (i.e., a
file that does not refer to model element definitions in other files or namespaces). Whenever models
are loaded that could contain such references, or you want to load a model element by URN, the
AspectModelLoader relies on so-called resolution strategies. A resolution strategy is a function
that takes a model element identifier (a model element URN) as an input and returns the content of
the file that contains the corresponding model element definition. Note that this is not necessarily
a file in the local filesystem, but it could also be a remote file or even exist only virtually as a
collection of statements in an RDF triple store. Several ResolutionStrategy
s are provided
that can be instantiated and passed to the AspectModelLoader
constructor to enable it to find
model element definitions:
-
The
FileSystemStrategy
resolves elements from files in the file system which are either structured in the models directory structure or exist as flat list of files in one directory (by usingFileSystemStrategy
with aFlatModelsRoot
). -
The
ClassPathStrategy
resolves model elements from resources in the Java class path. -
The
FromLoadedFileStrategy
resolves model elements from anAspectModelFile
that already resides in memory. -
The
EitherStrategy
can be used to chain two or more differentResolutionStrategy
s. -
The
ExternalResolverStrategy
delegates resolution to an external command such as a script; it is used in the implementation of the--custom-resolver
option of the samm-cli.
In addition, custom resolution strategies can be provided by implementing the ResolutionStrategy
interface.
The following example demonstrates how to pass a custom instance of a ResolutionStrategy
and resolve a model
element by URN:
Show used imports
import java.io.File;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.aspectmodel.resolver.FileSystemStrategy;
import org.eclipse.esmf.aspectmodel.resolver.ResolutionStrategy;
import org.eclipse.esmf.aspectmodel.urn.AspectModelUrn;
import org.eclipse.esmf.metamodel.AspectModel;
import org.eclipse.esmf.metamodel.vocabulary.SammNs;
import org.apache.jena.vocabulary.RDF;
// The directory containing the models folder structure,
// see models directory structure
final Path modelsRoot = Paths.get( "aspect-models" );
final ResolutionStrategy fileSystemStrategy = new FileSystemStrategy( modelsRoot );
final AspectModelUrn urn = AspectModelUrn.fromUrn( "urn:samm:org.eclipse.esmf.examples.movement:1.0.0#Movement" );
final AspectModel result = new AspectModelLoader( fileSystemStrategy ).load( urn );
Loading an Aspect Model to work on the RDF Level
The following example shows how to use the AspectModelLoad
to load an Aspect Model.
Show used imports
import java.io.File;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.aspectmodel.resolver.FileSystemStrategy;
import org.eclipse.esmf.aspectmodel.resolver.ResolutionStrategy;
import org.eclipse.esmf.aspectmodel.urn.AspectModelUrn;
import org.eclipse.esmf.metamodel.AspectModel;
import org.eclipse.esmf.metamodel.vocabulary.SammNs;
import org.apache.jena.vocabulary.RDF;
final AspectModel aspectModel = new AspectModelLoader().load(
// a File, InputStream or AspectModelUrn
);
// Do something with the Aspect Model on the RDF level.
// Example: List the URNs of all samm:Entitys
aspectModel.mergedModel().listStatements( null, RDF.type, SammNs.SAMM.Entity() )
.forEachRemaining( statement -> System.out.println( statement.getSubject().getURI() ) );
After loading an AspectModel
using the AspectModelLoader
, you can access the mergedModel()
on the
AspectModel
, which represents the merged RDF graph of all source files that were loaded in the model and
therefore contains all transitively referenced model element definitions. Alternatively, you can also access
the sourceModel()
of each Aspect Model file given by files()
, which will return only the RDF graph of this
file.
Serializing a Java Aspect Model into a RDF/Turtle Aspect Model
The serialize an Aspect into its corresponding RDF/Turtle representation, you can use the AspectSerializer
,
as demonstrated in the example below:
Show used imports
import java.io.File;
import org.eclipse.esmf.aspectmodel.AspectModelFile;
import org.eclipse.esmf.aspectmodel.serializer.AspectSerializer;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
// A String that contains the pretty printed Aspect Model
final String aspectString =
AspectSerializer.INSTANCE.aspectToString( aspectModel.aspect() );
Alternatively, you can also serialize a complete AspectModelFile
:
AspectModelFile aspectModelFile = // ...
final String fileString =
AspectSerializer.INSTANCE.aspectModelFileToString( aspectModelFile );
To include the serializer artifact, use the following dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-serializer</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-serializer:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-serializer:2.9.7")
Validating Aspect Models
Aspect Models are validated using the AspectModelValidator
. Validation returns a list of
Violation
s. A violation has a human-readable message and a unique error code and provides access
to the EvaluationContext
which contains references to the model element that caused the
violation and the SHACL shape that triggered the violation.
Each possible type of violation is a subtype of the Violation
interface and provides additional
context information specific to this type, for example, the MinLengthViolation
provides int min
(the allowed length) and int actual
(the length that was encountered in the model).
Consider the following example:
Show used imports
import java.io.File;
import java.util.List;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.aspectmodel.shacl.violation.Violation;
import org.eclipse.esmf.aspectmodel.validation.services.AspectModelValidator;
import org.eclipse.esmf.aspectmodel.validation.services.DetailedViolationFormatter;
import org.eclipse.esmf.aspectmodel.validation.services.ViolationFormatter;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final List<Violation> violations = new AspectModelValidator().validateModel( aspectModel );
if ( violations.isEmpty() ) {
// Aspect Model is valid!
return;
}
final String validationReport = new ViolationFormatter().apply( violations ); (1)
final String detailedReport = new DetailedViolationFormatter().apply( violations );
class MyViolationVisitor implements Violation.Visitor<String> { (2)
// ...
}
// Turn the list of Violations into a list of custom descriptions
final Violation.Visitor<String> visitor = new MyViolationVisitor();
final List<String> result = violations.stream()
.map( violation -> violation.accept( visitor ) )
.toList();
1 | To format the validation result into an human-readable form, use the ViolationFormatter or the
DetailedViolationFormatter . Note that those are only intended for text-based interfaces such as
CLIs. |
2 | Every application dealing with validation results that needs to transform the results into some
different structure can implement the Violation.Visitor Interface with a suitable target
type (String used as an example here) and use the visitor to handle the different types of
Violations in a type-safe way. |
The AspectModelValidator
also provides the loadModel(Supplier<AspectModel>)
method that can be used in
conjunction with () → new AspectModeLoader().load(…)
to have exceptions that might be created during the
Aspect Model loading process, for example due to model resolution failures or syntax errors in the input
files, be turned into a List<Violation>
that can be passed to the aforementioned violation formatters. This
allows for custom structured handling of problems that occur during model loading.
To include the model validator, use the following dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-validator</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-validator:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-validator:2.9.7")
Generating Documentation for Aspect Models
Different types of artifacts can be generated from an Aspect model. All corresponding generators are included in the following dependency:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-document-generators</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-document-generators:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-document-generators:2.9.7")
The documentation generation APIs provide methods that take as an argument a Function<String, java.io.OutputStream>
.
This is a mapping function that takes a file name as an input (which is determined by the respective generator) and
returns a corresponding OutputStream
, for example (but not necessarily) a FileOutputStream
. By providing this
function when calling the generator method, you can control where the output is written to, even when the generator
creates multiple files. For the code examples in the following subsections, we assume that the following method is
defined for calling the generators:
OutputStream outputStreamForName( final String aspectFileName ) {
// Create an OutputStream for the file name, e.g. a FileOutputStream
}
Generating SVG or PNG Diagrams
Using the AspectModelDiagramGenerator
, automatically layouted diagrams can be created for Aspect models in
the formats PNG and SVG.
Show used imports
import java.io.OutputStream;
import java.util.Locale;
import java.util.Set;
import org.eclipse.esmf.aspectmodel.generator.diagram.AspectModelDiagramGenerator;
import org.eclipse.esmf.aspectmodel.generator.diagram.AspectModelDiagramGenerator.Format;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final AspectModelDiagramGenerator generator = new AspectModelDiagramGenerator( aspectModel.aspect() ); (1)
// Variant 1: Generate a diagram in SVG format using @en descriptions and preferredNames from the model
final OutputStream output = outputStreamForName( "diagram.svg" );
generator.generateDiagram( Format.SVG, Locale.ENGLISH, output ); (2)
output.close();
// Variant 2: Generate diagrams in multiple formats, for all languages that are present in the model.
generator.generateDiagrams( Set.of( Format.PNG, Format.SVG ), this::outputStreamForName ); (3)
1 | The diagram generator is initialized with the loaded model. |
2 | The simple call for one output format and one language (i.e., descriptions and preferredNames of one locale) takes one output stream to write the image to. |
3 | It is also possible to generate multiple diagrams, one for each combination of output format and language. For that, the set of target formats is given as well as a mapping function. |
Generating HTML Documentation
A HTML reference documentation for an Aspect model can be generated as shown in the following code sample. The documentation contains an overview diagram and describes the model elements as specified in the Aspect model. Preferred names and descriptions in the respective language from the Aspect model are shown in the resulting document as part of each model element.
Show used imports
import java.io.File;
import java.io.IOException;
import java.util.Map;
import org.eclipse.esmf.aspectmodel.generator.docu.AspectModelDocumentationGenerator;
import org.eclipse.esmf.aspectmodel.generator.docu.AspectModelDocumentationGenerator.HtmlGenerationOption;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// end:imports[]
import org.junit.jupiter.api.Test;
public class GenerateHtml extends AbstractGenerator {
@Test
public void generate() throws IOException {
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final AspectModelDocumentationGenerator generator = (1)
new AspectModelDocumentationGenerator( aspectModel.aspect() );
final Map<HtmlGenerationOption, String> options = Map.of(); (2)
generator.generate( this::outputStreamForName, options );
}
}
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final AspectModelDocumentationGenerator generator = (1)
new AspectModelDocumentationGenerator( aspectModel.aspect() );
final Map<HtmlGenerationOption, String> options = Map.of(); (2)
generator.generate( this::outputStreamForName, options );
1 | The HTML generator is initialized with the context consisting of the loaded RDF model and the selected Aspect. |
2 | HTML generation can be controlled via a map of options; using an empty map implies default values. |
Generating Sample JSON Payload
The sample JSON payload generator is used to create a valid JSON payload for an Aspect model as it could be returned by
an Aspect that implements that Aspect model. This follows the
mapping rules as defined in the Meta Model specification.
The generator uses samm:exampleValue
s of Properties if present, otherwise random values corresponding to the
respective data types are generated.
Show used imports
import org.eclipse.esmf.aspectmodel.generator.json.AspectModelJsonPayloadGenerator;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final AspectModelJsonPayloadGenerator generator = new AspectModelJsonPayloadGenerator( aspectModel.aspect() );
// Variant 1: Direct generation into a String
final String jsonString = generator.generateJson();
// Variant 2: Generate using mapping function
generator.generateJson( this::outputStreamForName );
Generating JSON Schema
The JSON schema generator creates a JSON Schema that describes the payload for an Aspect model as it could be returned by an Aspect that implements that Aspect model.
Show used imports
import java.io.ByteArrayOutputStream;
import java.util.Locale;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.eclipse.esmf.aspectmodel.generator.jsonschema.AspectModelJsonSchemaGenerator;
import org.eclipse.esmf.aspectmodel.generator.jsonschema.JsonSchemaGenerationConfig;
import org.eclipse.esmf.aspectmodel.generator.jsonschema.JsonSchemaGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final JsonSchemaGenerationConfig config = JsonSchemaGenerationConfigBuilder.builder()
.locale( Locale.ENGLISH )
.build();
final JsonNode jsonSchema = AspectModelJsonSchemaGenerator.INSTANCE.apply( aspectModel.aspect(), config ).getContent();
// If needed, print or pretty print it into a string
final ByteArrayOutputStream out = new ByteArrayOutputStream();
final ObjectMapper objectMapper = new ObjectMapper();
objectMapper.writerWithDefaultPrettyPrinter().writeValue( out, jsonSchema );
final String result = out.toString();
Generating OpenAPI Specification
The OpenAPI specification generator creates either a JSON Schema or a Yaml Spec that specifies an Aspect regarding to the OpenApi specification. The currently used versions corresponds Draft 4 of the JSON Schema specification, and 3.0.1.
Show used imports
import java.io.ByteArrayOutputStream;
import org.eclipse.esmf.aspectmodel.generator.openapi.AspectModelOpenApiGenerator;
import org.eclipse.esmf.aspectmodel.generator.openapi.OpenApiSchemaGenerationConfig;
import org.eclipse.esmf.aspectmodel.generator.openapi.OpenApiSchemaGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.generator.openapi.PagingOption;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final OpenApiSchemaGenerationConfig config = OpenApiSchemaGenerationConfigBuilder.builder()
// Server URL
.baseUrl( "http://www.example.com" )
// The resource path which shall be added
.resourcePath( "/testPath/{parameter}" )
// Determines whether semantic versioning should be used for the API
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// A String containing all the information for dynamic properties mentioned in the resource path.
// The string must be syntactically valid YAML.
.properties( readYaml( """
parameter:
name: parameter
in: path
description: "A parameter."
required: true
schema:
type: string
""" ) )
// Should the query API be added to the generated specification?
.includeQueryApi( true )
// The paging Option to be chosen. In case paging is possible:
// The default for a time related collection is time-based paging.
// Otherwise the default is offset-based paging.
.pagingOption( PagingOption.OFFSET_BASED_PAGING )
.build();
// Generate pretty-printed YAML
final AspectModelOpenApiGenerator generator = new AspectModelOpenApiGenerator();
final String yaml = generator.apply( aspectModel.aspect(), config ).getContentAsYaml();
}
@Test
public void generateJson() throws IOException {
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final ObjectMapper objectMapper = new ObjectMapper();
final OpenApiSchemaGenerationConfig config = OpenApiSchemaGenerationConfigBuilder.builder()
// Server URL
.baseUrl( "http://www.example.com" )
// The resource path which shall be added
.resourcePath( "/testPath/{parameter}" )
// Determines whether semantic versioning should be used for the API
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// A JsonNode containing all the information for variable properties mentioned
// in the resource path .
.properties( readYaml( """
{
"test-Id": {
"name": "test-Id",
"in": "path",
"description": "The ID of the unit.",
"required": true,
"schema": {
"type": "string"
}
}
}
""" ) )
// Should the query API be added to the generated specification?
.includeQueryApi( true )
// The paging Option to be chosen. In case paging is possible:
// The default for a time related collection is time-based paging.
// Otherwise the default is offset-based paging.
.pagingOption( PagingOption.OFFSET_BASED_PAGING )
.build();
// Generate the JSON
final AspectModelOpenApiGenerator generator = new AspectModelOpenApiGenerator();
final JsonNode json = generator.apply( aspectModel.aspect(), config ).getContent();
// If needed, print or pretty print it into a string
final ByteArrayOutputStream out = new ByteArrayOutputStream();
objectMapper.writerWithDefaultPrettyPrinter().writeValue( out, json );
final String result = out.toString();
}
private static ObjectNode readYaml( String content ) throws JsonProcessingException {
return (ObjectNode) new YAMLMapper().readTree( content );
}
}
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final ObjectMapper objectMapper = new ObjectMapper();
final OpenApiSchemaGenerationConfig config = OpenApiSchemaGenerationConfigBuilder.builder()
// Server URL
.baseUrl( "http://www.example.com" )
// The resource path which shall be added
.resourcePath( "/testPath/{parameter}" )
// Determines whether semantic versioning should be used for the API
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// A JsonNode containing all the information for variable properties mentioned
// in the resource path .
.properties( readYaml( """
{
"test-Id": {
"name": "test-Id",
"in": "path",
"description": "The ID of the unit.",
"required": true,
"schema": {
"type": "string"
}
}
}
""" ) )
// Should the query API be added to the generated specification?
.includeQueryApi( true )
// The paging Option to be chosen. In case paging is possible:
// The default for a time related collection is time-based paging.
// Otherwise the default is offset-based paging.
.pagingOption( PagingOption.OFFSET_BASED_PAGING )
.build();
// Generate the JSON
final AspectModelOpenApiGenerator generator = new AspectModelOpenApiGenerator();
final JsonNode json = generator.apply( aspectModel.aspect(), config ).getContent();
// If needed, print or pretty print it into a string
final ByteArrayOutputStream out = new ByteArrayOutputStream();
objectMapper.writerWithDefaultPrettyPrinter().writeValue( out, json );
final String result = out.toString();
}
private static ObjectNode readYaml( String content ) throws JsonProcessingException {
return (ObjectNode) new YAMLMapper().readTree( content );
}
}
For Enumerations with complex data types, the values are modelled as instances of the Entity defined as the Enumeration’s data type (see Declaring Enumerations for more information). In case the Entity instances contain Properties with a sorted collection as their data type, the order of the values of said collection in the Entity instances is not preserved in the generated OpenAPI specification. Preserving this order in OpenAPI is not possible at this point. |
Generating AsyncAPI Specification
The AsyncAPI specification generator creates either a JSON Schema or a Yaml Spec that specifies an Aspect regarding to the AsyncApi specification. The currently used versions correspond to Draft 4 of the JSON Schema specification, and 3.0.0 of the AsyncAPI specification.
Show used imports
import java.io.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import org.eclipse.esmf.aspectmodel.generator.asyncapi.AspectModelAsyncApiGenerator;
import org.eclipse.esmf.aspectmodel.generator.asyncapi.AsyncApiSchemaGenerationConfig;
import org.eclipse.esmf.aspectmodel.generator.asyncapi.AsyncApiSchemaGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final ObjectMapper yamlMapper = new YAMLMapper().enable( YAMLGenerator.Feature.MINIMIZE_QUOTES );
final AsyncApiSchemaGenerationConfig config = AsyncApiSchemaGenerationConfigBuilder.builder()
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// Set Application id
.applicationId( "test:serve" )
.channelAddress( "/123-456/789-012/movement/0.0.1/Movement" )
.build();
// Generate pretty-printed YAML
final AspectModelAsyncApiGenerator generator = new AspectModelAsyncApiGenerator();
final JsonNode json = generator.apply( aspectModel.aspect(), config ).getContent();
final String yaml = yamlMapper.writeValueAsString( json );
final ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write( yaml.getBytes( StandardCharsets.UTF_8 ) );
final String result = out.toString();
}
@Test
public void generateJson() throws IOException {
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final ObjectMapper objectMapper = new ObjectMapper();
final AsyncApiSchemaGenerationConfig config = AsyncApiSchemaGenerationConfigBuilder.builder()
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// Set Application id
.applicationId( "test:serve" )
.channelAddress( "/123-456/789-012/movement/0.0.1/Movement" )
.build();
// Generate the JSON
final AspectModelAsyncApiGenerator generator = new AspectModelAsyncApiGenerator();
final JsonNode json = generator.apply( aspectModel.aspect(), config ).getContent();
// If needed, print or pretty print it into a string
final ByteArrayOutputStream out = new ByteArrayOutputStream();
objectMapper.writerWithDefaultPrettyPrinter().writeValue( out, json );
final String result = out.toString();
}
}
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
new AspectModelLoader().load(
new File( "aspect-models/org.eclipse.esmf.examples.movement/1.0.0/Movement.ttl" ) );
final ObjectMapper objectMapper = new ObjectMapper();
final AsyncApiSchemaGenerationConfig config = AsyncApiSchemaGenerationConfigBuilder.builder()
// i.e., true = v1.2.3, false = v1
.useSemanticVersion( false )
// Set Application id
.applicationId( "test:serve" )
.channelAddress( "/123-456/789-012/movement/0.0.1/Movement" )
.build();
// Generate the JSON
final AspectModelAsyncApiGenerator generator = new AspectModelAsyncApiGenerator();
final JsonNode json = generator.apply( aspectModel.aspect(), config ).getContent();
// If needed, print or pretty print it into a string
final ByteArrayOutputStream out = new ByteArrayOutputStream();
objectMapper.writerWithDefaultPrettyPrinter().writeValue( out, json );
final String result = out.toString();
}
}
Generating SQL for Aspect Models
Using the Aspect Model SQL generator, an SQL script can be generated that sets up a table for data corresponding to the Aspect. The current implementation provides support for the Databricks SQL dialect and a mapping strategy that uses a denormalized table, i.e., the table contains one column for each Property used in the Aspect Model (or any of its transitively referenced Entities).
Show used imports
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import java.util.Optional;
import org.eclipse.esmf.aspectmodel.generator.sql.AspectModelSqlGenerator;
import org.eclipse.esmf.aspectmodel.generator.sql.SqlGenerationConfig;
import org.eclipse.esmf.aspectmodel.generator.sql.SqlGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.generator.sql.databricks.DatabricksColumnDefinitionBuilder;
import org.eclipse.esmf.aspectmodel.generator.sql.databricks.DatabricksSqlGenerationConfig;
import org.eclipse.esmf.aspectmodel.generator.sql.databricks.DatabricksSqlGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.generator.sql.databricks.DatabricksType;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final DatabricksSqlGenerationConfig databricksSqlGenerationConfig =
DatabricksSqlGenerationConfigBuilder.builder()
.commentLanguage( Locale.ENGLISH ) // optional
.includeTableComment( true ) // optional
.includeColumnComments( true ) // optional
.decimalPrecision( 10 ) // optional
.customColumns( List.of( // optional
DatabricksColumnDefinitionBuilder.builder()
.name( "custom_column" )
.type( new DatabricksType.DatabricksArray( DatabricksType.STRING ) )
.nullable( false )
.comment( Optional.of( "Custom column" ) )
.build() ) )
.build();
final SqlGenerationConfig sqlGenerationConfig =
SqlGenerationConfigBuilder.builder()
.dialect( SqlGenerationConfig.Dialect.DATABRICKS )
.mappingStrategy( SqlGenerationConfig.MappingStrategy.DENORMALIZED )
.dialectSpecificConfig( databricksSqlGenerationConfig )
.build();
final String result = AspectModelSqlGenerator.INSTANCE.apply( aspectModel.aspect(), sqlGenerationConfig ).getContent();
Databricks Type Mapping
Data types in the Aspect Model are mapped to Databricks types using the following correspondences:
Aspect model type | Databricks SQL type | Note |
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While xsd:decimal is by definition unbounded, DECIMAL’s default precision is 10 digits and can be up to 38. if we assume values larger than that can appear in the data, the Aspect Models using xsd:decimal should also use a samm-c:FixedPointConstraint accordingly. |
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Generating Java Code for Aspect Models
Java code can be generated from an Aspect model in two ways:
-
The generated code represents the Aspect payload. Aspects and Entities become Java classes; their Properties become fields in the classes. Characteristics are not first-class elements, but are implicitly represented by the usage of corresponding data types (e.g. using
java.util.Set
as the type for theSet
Characteristic of a Property) orjavax.validation
annotations. The generated classes can be used in a straightforward fashion, but they do not contain information about the underlying Aspect model such as its version number. Parts of the Aspect model that have no representation in its corresponding JSON payload are not part of those classes either, in particular descriptions and preferred names. These classes are called POJOs (Plain Old Java Objects), as they do not contain logic but serve mainly as data containers. -
The generated code represents the Aspect model itself: It is a type-safe variant of the model and includes every information that is also present in the model such as Characteristics, descriptions including language tags and original XSD data types. It is however not intended to store payload corresponding to an Aspect. Theses classes are called static meta classes, because they are created at compile time (static) and talk about the structure of the information, not the information itself (meta).
Depending on the use case, you would either use one or both of the types simultaneously.
To include the Java generator, use the following dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-model-java-generator</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-java-generator:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-java-generator:2.9.7")
Type Mapping
In the Java code generated from an Aspect model, the scalar Aspect model data types are mapped to native Java types. The following table lists the correspondences.
Aspect model type | Java native type |
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Generating POJOs
POJO generation is straightforward; there are two minor differences to the generation of documentation artifacts.
Firstly, when instantiating the generator, you pass a flag indicating whether
Jackson annotations should be generated in the class. Secondly, the name
mapping function passed to the generation method takes a QualifiedName
instead of a String, so that you can decide how
to handle the package structure of the class.
Show used imports
import org.eclipse.esmf.aspectmodel.java.JavaCodeGenerationConfig;
import org.eclipse.esmf.aspectmodel.java.JavaCodeGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.java.pojo.AspectModelJavaGenerator;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
import java.io.File;
import org.apache.commons.io.output.NullOutputStream;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final JavaCodeGenerationConfig config = JavaCodeGenerationConfigBuilder.builder()
.enableJacksonAnnotations( true )
.packageName( "com.example.mycompany" ) // if left out, package is taken from Aspect's namespace
.build();
final AspectModelJavaGenerator generator = new AspectModelJavaGenerator( aspectModel.aspect(), config );
generator.generate( qualifiedName -> {
// Create an output stream for the given qualified Java class name
} );
Generating Static Meta Classes
For the generation of static meta classes, consider the following example:
Show used imports
import org.eclipse.esmf.aspectmodel.java.JavaCodeGenerationConfig;
import org.eclipse.esmf.aspectmodel.java.JavaCodeGenerationConfigBuilder;
import org.eclipse.esmf.aspectmodel.java.metamodel.StaticMetaModelJavaGenerator;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final JavaCodeGenerationConfig config = JavaCodeGenerationConfigBuilder.builder()
.enableJacksonAnnotations( true )
.packageName( "com.example.mycompany" ) // if left out, package is taken from Aspect's namespace
.build();
final StaticMetaModelJavaGenerator generator = new StaticMetaModelJavaGenerator( aspectModel.aspect(), config );
generator.generate( qualifiedName -> {
// Create an output stream for the given qualified Java class name
} );
To use the generated static meta classes, you need the following additional dependency:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-static-meta-model-java</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-static-meta-model-java:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-static-meta-model-java:2.9.7")
Providing Custom Macros for Code Generation
It is possible to change predefined sections of the generated classes by providing custom Velocity templates; see the Velocity User Guide for more information. The custom macros must be defined in a single template file. The path to the template file as well as its name may be passed as arguments to the code generation, e.g. using the SAMM-CLI.
Custom macros may be provided for the following sections:
Section | Macro Name | Default Macro Provided |
---|---|---|
Copyright Licence Header |
fileHeader |
When using custom macros, macros for all sections above must be provided. |
Example:
#macro( fileHeader )
/*
* Copyright (c) $currentYear.getValue() Test Inc. All rights reserved.
*/
#end
Modifying and creating Aspect Models
You can use the AspectChangeManager
to modify an Aspect Model. Each modifying operation performed
on an Aspect Model is called a change. Instances of classes that implement the Change
interface
can be passed to the AspectChangeManager
applyChange()
method. Available Change
s
include renaming Aspect Model files or Model elements, adding and removing Aspect Model files and
moving Aspect Model elements to other or new files in the same or another namespace.
Show used imports
import java.io.File;
import java.net.URI;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import org.eclipse.esmf.aspectmodel.edit.AspectChangeManager;
import org.eclipse.esmf.aspectmodel.edit.AspectChangeManagerConfig;
import org.eclipse.esmf.aspectmodel.edit.AspectChangeManagerConfigBuilder;
import org.eclipse.esmf.aspectmodel.edit.Change;
import org.eclipse.esmf.aspectmodel.edit.ChangeGroup;
import org.eclipse.esmf.aspectmodel.edit.ChangeReport;
import org.eclipse.esmf.aspectmodel.edit.ChangeReportFormatter;
import org.eclipse.esmf.aspectmodel.edit.change.MoveElementToNewFile;
import org.eclipse.esmf.aspectmodel.edit.change.RenameElement;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
final AspectModel aspectModel = new AspectModelLoader().load(
// a File, InputStream or AspectModelUrn
);
// All changes to an Aspect Model are done using an AspectChangeManager.
// Optionally, you can pass a config object as first constructor argument:
final AspectChangeManagerConfig config = AspectChangeManagerConfigBuilder.builder()
.detailedChangeReport( true )
.defaultFileHeader( List.of( "Generated on "
+ new SimpleDateFormat( "dd-MM-yyyy" ).format( new Date() ) ) )
.build();
final AspectChangeManager changeManager = new AspectChangeManager( config, aspectModel );
// You can create a single change, or you can combine multiple changes into a group.
// For all possible refactoring operations, see classes implementing the Change interface.
final Change refactorModel = new ChangeGroup( List.of(
// Rename an element. This works with with samm:Aspect and all other model elements.
new RenameElement( aspectModel.aspect(), "MyAspect" ),
// Move an element to a new Aspect Model file in the same namespace.
new MoveElementToNewFile(
// The element to move.
aspectModel.aspect().getProperties().get( 0 ),
// If you intend to write the model to the file system, set the location
// for the newly created file to some sensible location here.
URI.create( "file:///temp/out.ttl" ) )
) );
// Apply the changes and get a report that summerizes the changes.
final ChangeReport changeReport = changeManager.applyChange( refactorModel );
// If you want to display the change report, you can serialize it to a string:
ChangeReportFormatter.INSTANCE.apply( changeReport, config );
// Alternatively, you can also get views on collections containing modified/
// added/removed files for the last applied change.
changeManager.createdFiles().forEach( file -> System.out.println( "Created: " + file ) );
changeManager.modifiedFiles().forEach( file -> System.out.println( "Modified: " + file ) );
changeManager.removedFiles().forEach( file -> System.out.println( "Removed: " + file ) );
// At this point, you could use the AspectChangeManager's undo() method to revert
// the last change (refactorModel in this case); afterwards you can also redo().
// This functionality is mainly interesting when refactoring the Aspect Model
// interactively.
// If you want to write the model changes to the file system, use the AspectSerializer.
// Each AspectModelFile will be written to its respective source location.
// Alternatively, the AspectSerializer also provides a method to write an AspectModelFile
// into a String.
AspectSerializer.INSTANCE.write( aspectModel );
Accessing the SAMM programmatically
In order to access the source RDF files that describe the SAMM vocabulary, shared Characteristics and Entities
as well as Units, you can add a dependency to the esmf-aspect-meta-model
artifact. Note that this artifact
does not provide Java classes that represent the meta model.
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-semantic-aspect-meta-model</artifactId> <version>2.1.0</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-semantic-aspect-meta-model:2.1.0'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-semantic-aspect-meta-model:2.1.0")
In order to access the files via java.lang.Class#getResourceAsStream
, you can refer to the following directory
structure that is present in the artifact:
.
├── characteristic
│ └── 2.1.0
│ ├── characteristic-definitions.ttl
│ ├── characteristic-instances.ttl
│ ├── characteristic-shapes.ttl
│ └── characteristic-validations.js
├── entity
│ └── 2.1.0
│ ├── FileResource.ttl
│ ├── ThreeDimensionalPosition.ttl
│ └── TimeSeriesEntity.ttl
├── meta-model
│ └── 2.1.0
│ ├── aspect-meta-model-definitions.ttl
│ ├── aspect-meta-model-shapes.ttl
│ ├── prefix-declarations.ttl
│ └── type-conversions.ttl
└── unit
└── 2.1.0
└── units.ttl
You can use the MetaModelFile enumeration provided by the esmf-aspect-meta-model-java module to
access object representations of the meta model files, for example:
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Show used imports
import org.apache.jena.rdf.model.Model;
import org.apache.jena.vocabulary.RDF;
import org.eclipse.esmf.aspectmodel.resolver.modelfile.MetaModelFile;
import org.eclipse.esmf.metamodel.vocabulary.SammNs;
import org.eclipse.esmf.samm.KnownVersion;
final KnownVersion metaModelVersion = KnownVersion.getLatest();
final Model characteristicDefinitions = MetaModelFile.CHARACTERISTIC_DEFINITIONS.sourceModel();
// Do something with the org.apache.jena.org.rdf.model.Model
final int numberOfCharacteristicInstances =
characteristicDefinitions.listStatements( null, RDF.type, SammNs.SAMM.Characteristic() ).toList().size();
final String result = String.format( "Meta Model Version " + metaModelVersion.toVersionString()
+ " defines " + numberOfCharacteristicInstances + " Characteristic instances" );
Mapping Aspect Models to Asset Administration Shell (AAS) Submodel Templates
The Asset Administration Shell (AAS) and its information model is a widely recognized standard developed by the Industrial Digital Twin Association (IDTA) to express and handle Digital Twins. Central element of the AAS is the concept of Submodels, which describe certain aspects of a Digital Twin.
The SAMM Aspect Meta Model allows to specify aspects of a digital twin and its semantics. The AAS Generator module provides mapping implementations to derive AAS Submodels from SAMM Aspect Models. On the one hand, this allows to integrate SAMM models in AAS environments and on the other hand it allows AAS submodels to be described with rich semantics, as it is possible with SAMM.
Details of the Mapping Concept
In the following section, the mapping rules applied by the generator are explained. The rules apply to SAMM v2.0.0 and AAS Specification Part 1 V3.0RC01.
SAMM | AAS | Comment |
---|---|---|
samm:Aspect |
aas:Submodel with kind=Template |
Empty Asset and AssetAdministrationShell entries are added to the output file |
samm:name |
aas:Submodel.idShort |
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samm:preferredName |
aas:Submodel.displayName |
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samm:description |
aas:Submodel.description |
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samm:property |
see samm:Property |
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samm:operation |
see samm:Operation |
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samm:Aspect.urn |
aas:Submodel.semanticId |
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samm:Property |
aas:Property, aas:SubmodelElementCollection |
The AAS type is derived from the type of the SAMM Characteristic specifying the SAMM property. Depending on the type it is decided what the resulting AAS element will be. In case of an Entity it will result in a SubmodelElementCollection. It will also be a SubmodelElementCollection if the SAMM Characteristic is of a Collection type (see the Characteristics taxonomy). In all other cases an aas:Property will be generated |
samm:Property.name |
aas:Property.idShort |
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samm:Property.urn |
aas:ConceptDescription.identification.id, aas:Property.semanticId |
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samm:Property.preferredName |
aas:Property.displayName |
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samm:Property.description |
aas:Property.description |
Note: Also mapped to aas:DataSpecificationIEC61360.definition of the aas:ConceptDescription of this property |
samm:Property.exampleValue |
aas:Property.value |
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samm:Characteristic.dataType |
aas:Property.valueType |
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samm:Operation |
Operation |
in/out parameters are not used in SAMM so the mapping only generates input variables and output variables in AAS |
aas:SubmodelElement, aas:ConceptDescription |
Characteristics in SAMM define the semantics of a property, which includes there types as well as links to further definitions (standards, dictionaries, etc), a natural language description and name in different languages. Type and description are separated in AAS, which is why there is not a one-to-one mapping of a Characteristic to one element in AAS but rather Characteristics are used in the mapping of Properties, first, to guide the generation process and, second, to capture semantics in ConceptDescriptions of properties with data specification "DataSpecificationIEC61360" of the AAS. |
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aas:SubmodelElementList, aas:ConceptDescription |
The general remarks to Characteristics apply also to Collection type Characteristics. However, properties referencing Collections are mapped to SubmodelElementLists. Specific properties of collections are mapped. samm:Set is unique, samm:SortedSet is unique and sorted, samm:List is sorted. |
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aas:SubmodelElement, aas:ConceptDescription |
The general remarks to Characteristics apply also to Quantifiable type Characteristics. Quantifiables (also Duration and Measurement) reference a unit, which is added to the ConceptDescription corresponding the mapped Characteristic. |
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aas:SubmodelElement, aas:ConceptDescription |
The general remarks to Characteristics apply also to Either. However, the Either characteristic has two distinct entries of which one is to be selected. This concept is not present in AAS. Thus, both entries will be written to a Submodel template, where one has to be ignored. |
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aas:SubmodelElement, aas:ConceptDescription |
The general remarks to Characteristics apply also to Trait. However, the constraint of a trait will be ignored and only the base type will be evaluated, which will act as the characteristic of a property. |
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aas:SubmodelElement, aas:ConceptDescription |
Similar to plain Characteristic. |
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aas:SubmodelElement, aas:ConceptDescription |
The general remarks to Characteristics apply also to StructuredValue. However, AAS has no concpet like deconstruction rule. Thus, the deconstruction rule and the sub properties of the deconstruction entity will be ignored and only the Characteristic is mapped. |
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aas:SubmodelElement, aas:ConceptDescription |
The general remarks to Characteristics apply also to Enumerations. Additionally, the values of an Enumeration are mapped to a valueList of a DataSpecificationIEC61360. |
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aas:SubmodelElement, aas:ConceptDescription |
Same as Enumeration. |
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aas:MultiLanguageProperty |
if a MultiLanguageText is used in SAMM it is mapped to the MultiLanguageProperty in AAS. |
Known Limitations
The AAS Generator implements a base set of features, which are mapped from SAMM to AAS. However, there are still limitations:
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Predefined entity mapping (FileResource would be mapped to aas:File)
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samm-c:Either is mapped to aas:SubmodelElementCollection with two entries for left and right side
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Recursive optional properties of SAMM model are not included in output but dropped straight away
Translate Aspect Model to AAS
The following code demonstrates how the API to translate an Aspect Model into one of the valid AAS formats (JSON, XML, AASX) is used:
Show used imports
import org.eclipse.esmf.aspectmodel.aas.AspectModelAasGenerator;
import org.eclipse.esmf.aspectmodel.aas.AasFileFormat;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.Aspect;
import org.eclipse.esmf.metamodel.AspectModel;
// AspectModel as returned by the AspectModelLoader
final AspectModel aspectModel = // ...
final AspectModelAasGenerator generator = new AspectModelAasGenerator();
// Generate AAS .aasx for input Aspect
generator.generate( AasFileFormat.AASX, aspect, this::outputStreamForName );
// Generate AAS .xml for input Aspect
generator.generate( AasFileFormat.XML, aspect, this::outputStreamForName );
// Generate AAS .json for input Aspect
generator.generate( AasFileFormat.JSON, aspect, this::outputStreamForName );
To include the translator artifact, use the following dependencies:
- Maven
-
<dependency> <groupId>org.eclipse.esmf</groupId> <artifactId>esmf-aspect-aas-generator</artifactId> <version>2.9.7</version> </dependency>
- Gradle Groovy DSL
-
implementation 'org.eclipse.esmf:esmf-aspect-model-aas-generator:2.9.7'
- Gradle Kotlin DSL
-
implementation("org.eclipse.esmf:esmf-aspect-model-aas-generator:2.9.7")
Translate AAS to Aspect Model
It is also possible to translate AAS Submodel Templates to Aspect Models using a best-effort. The following example shows how the API to translate an AAS environment containing one or more Submodel Templates to Aspect Models:
Show used imports
import java.io.File;
import java.util.List;
import org.eclipse.esmf.aspectmodel.aas.AasFileFormat;
import org.eclipse.esmf.aspectmodel.aas.AasToAspectModelGenerator;
import org.eclipse.esmf.aspectmodel.aas.AspectModelAasGenerator;
import org.eclipse.esmf.metamodel.Aspect;
import org.eclipse.esmf.aspectmodel.loader.AspectModelLoader;
import org.eclipse.esmf.metamodel.AspectModel;
final File file = // an AAS file that ends in .aasx, .xml or .json
// Multiple "from" methods are available: fromFile (which checks the file extension),
// fromAasJson, fromAasXml, fromAasx as well as fromEnvironment (for an AAS4J AAS environment)
final AasToAspectModelGenerator generator = AasToAspectModelGenerator.fromFile( file );
final List<Aspect> aspects = generator.generateAspects();
aspects.forEach( aspect -> {
// do something with the generated aspect
} );
To include the translator artifact, use the same same dependencies as shown above in section Translate AAS to Aspect Model.