30130 - add lazy loading for sdmx 3.0 and plus requests

sdmx30-infomodel/src/main/java/com/epam/jsdmx/infomodel/sdmx30/LazyMaintainableArtefactImpl.java

@@ -0,0 +1,58 @@
+package com.epam.jsdmx.infomodel.sdmx30;
+
+import java.util.Set;
+
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+public class LazyMaintainableArtefactImpl extends MaintainableArtefactImpl {
+
+    private boolean targetArtefact;
+    private ArtefactReference artefactReference;
+    private Set<CrossReference> referencedArtefacts;
+
+    public LazyMaintainableArtefactImpl(ArtefactReference reference) {
+        setId(reference.getId());
+        setVersion(Version.createFromString(reference.getVersionString()));
+        setOrganizationId(reference.getOrganisationId());
+        this.artefactReference = reference;
+    }
+
+    public LazyMaintainableArtefactImpl(MaintainableArtefact maintainableArtefact) {
+        super(maintainableArtefact);
+    }
+
+    @Override
+    public StructureClass getStructureClass() {
+        return artefactReference.getStructureClass();
+    }
+
+    @Override
+    public Set<CrossReference> getReferencedArtefacts() {
+        return referencedArtefacts;
+    }
+
+    @Override
+    public ArtefactReference toReference() {
+        return this.artefactReference;
+    }
+
+    @Override
+    public MaintainableArtefact toStub() {
+        return this;
+    }
+
+    @Override
+    public MaintainableArtefact toCompleteStub() {
+        return this;
+    }
+
+    @Override
+    protected MaintainableArtefactImpl createInstance() {
+        return this;
+    }
+}