add metamodel and api classes after latest run

[sebbader-sap]

Including these extensions:

• copyconstructor
• default values

[sebbader-sap]

Still open:

• Unit tests of the serialisers fail due to not yet updated "expected files"

[arnoweiss]

There's an issue with the way copy constructors are generated. Currently, for a SMEC, that looks like this:

    public DefaultSubmodelElementCollection(SubmodelElementCollection x) {
        this.embeddedDataSpecifications = x.getEmbeddedDataSpecifications();
        this.extensions = x.getExtensions();
        this.semanticId = x.getSemanticId();
        this.supplementalSemanticIds = x.getSupplementalSemanticIds();
        this.qualifiers = x.getQualifiers();
        this.category = x.getCategory();
        this.description = x.getDescription();
        this.displayName = x.getDisplayName();
        this.idShort = x.getIdShort();
        this.value = x.getValue();
    }

The copy is populated via getting the respective field from the original object. This creates only shallow copies! If a field requires something that's not either immutable or primitive, there will NOT be a new sub-object created. Meaning that copy.getDescription() will point to the exact same bytes in memory as original.getDescription().

Why this can lead to unexpected behavior as in the test below.

package org.eclipse.digitaltwin.aas4j.v3.model;


import org.eclipse.digitaltwin.aas4j.v3.model.builder.LangStringTextTypeBuilder;
import org.eclipse.digitaltwin.aas4j.v3.model.builder.PropertyBuilder;
import org.eclipse.digitaltwin.aas4j.v3.model.impl.DefaultLangStringTextType;
import org.eclipse.digitaltwin.aas4j.v3.model.impl.DefaultProperty;
import org.eclipse.digitaltwin.aas4j.v3.model.impl.DefaultSubmodelElementCollection;
import org.junit.Test;

import java.util.List;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;

public class CopyConstructorTest {
    @Test
    public void onProperty() {

        DefaultSubmodelElementCollection original = new DefaultSubmodelElementCollection.Builder()
                .value(new DefaultProperty.Builder()
                        .description(new DefaultLangStringTextType.Builder()
                                .language("en")
                                .text("MyDescription")
                                .build())
                        .build())
                .build();

        DefaultSubmodelElementCollection copy = new DefaultSubmodelElementCollection(original); // make copy

        assertEquals(getPropertyDescriptionTextFromSmec(original), getPropertyDescriptionTextFromSmec(copy)); // true
        
        copy.getValue().get(0).getDescription().get(0).setText("DifferentDescription"); // change value in copy

        assertNotEquals(
                getPropertyDescriptionTextFromSmec(original), 
                getPropertyDescriptionTextFromSmec(copy)
        );
        // Objects should be different. Copy was changed, the original was not. However, both hold "DifferentDescription".
        
    }

    private String getPropertyDescriptionTextFromSmec(SubmodelElementCollection smec) {
        String text = smec.getValue().get(0).getDescription().get(0).getText();
        System.out.println(text);
        return text;
    }
}

[sebbader-sap]

I need more time to design a deep copy pattern. Will keep this PR open as a reminder.

[emildinchev]

The old version seems better to me.

[emildinchev]

Most of the Metadata interfaces simply extends the SubmodelElementAttributes interface without any new definition. Are these new interfaces really needed?