String realmId = "coreExtension>" + extension.getGroupId() + ":" + extension.getArtifactId() + ":"
                + extension.getVersion();
        final ClassRealm realm = classWorld.newRealm(realmId, null);
        Set<String> providedArtifacts = Collections.emptySet();
        String classLoadingStrategy = extension.getClassLoadingStrategy();

            changed = true;
        } else {
            changed = metadata.merge(this.metadata);
        }

        // beware meta-versions!
        String version = metadata.getVersion();
        if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {
            // meta-versions are not valid <version/> values...don't write them.
            metadata.setVersion(null);

    }

    /**
     * Gets the effective version of the model.
     *
     * @return The effective version of the model or an empty string if unknown, never {@code null}.
     */
    public String getVersion() {
        return (version != null) ? version : "";
    }

    /**
     * Sets the effective version of the model.
     *
     * @param version The effective version of the model, may be {@code null}.

            final RESULT entity = createEntity(source, entityType);
            final DocMeta docMeta = ((EsAbstractEntity) entity).asDocMeta();
            docMeta.id(hit.getId());
            docMeta.version(hit.getVersion());
            docMeta.seqNo(hit.getSeqNo());
            docMeta.primaryTerm(hit.getPrimaryTerm());
            list.add(entity);
        });

        list.setPageSize(size);

    public PluginDescriptor(PluginDescriptor original) {
        this.setGroupId(original.getGroupId());
        this.setArtifactId(original.getArtifactId());
        this.setVersion(original.getVersion());
        this.setGoalPrefix(original.getGoalPrefix());
        this.setInheritedByDefault(original.isInheritedByDefault());
        this.setName(original.getName());

        return artifactId;
    }

    public String getGroupId() {
        return groupId;
    }

    public String getType() {
        return type;
    }

    public String getVersion() {
        return version;
    }

    public String getArtifactKey() {
        return groupId + ":" + artifactId + ":" + version + ":" + type;
    }

        ArtifactHandler artifactHandler = artifact.getArtifactHandler();

        StringBuilder path = new StringBuilder(128);

        path.append(artifact.getArtifactId()).append(ARTIFACT_SEPARATOR).append(artifact.getVersion());

        if (artifact.hasClassifier()) {
            path.append(ARTIFACT_SEPARATOR).append(artifact.getClassifier());
        }

        if (artifactHandler.getExtension() != null

    @Override
    public Model findModel(Artifact artifact) {
        if (GROUP_ID.equals(artifact.getGroupId())
                && ARTIFACT_ID.equals(artifact.getArtifactId())
                && VERSION.equals(artifact.getVersion())) {
            Model m = new Model();
            m.setArtifactId(ARTIFACT_ID);
            m.setGroupId(GROUP_ID);
            m.setVersion(VERSION);
            Repository repository = new Repository();

            Model model = (data.getModel() != null) ? data.getModel().clone() : null;
            return new ModelData(data.getSource(), model, data.getGroupId(), data.getArtifactId(), data.getVersion());
        }

        @Override
        public ModelData fromCache(ModelData data) {
            return intoCache(data);
        }
    };

    /**

        ArtifactMetadataAdapter(Metadata metadata) {
            this.metadata = metadata;
        }

        @Override
        public boolean storedInArtifactVersionDirectory() {
            return !metadata.getVersion().isEmpty();
        }

        @Override
        public boolean storedInGroupDirectory() {
            return metadata.getArtifactId().isEmpty();
        }

        @Override