platform/sensinact-core/src/main/java/org/eclipse/sensinact/gateway/core/MetadataDescription.java

/*
* Copyright (c) 2020 Kentyou.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
*    Kentyou - initial API and implementation
 */
package org.eclipse.sensinact.gateway.core;

import org.json.JSONObject;

import org.eclipse.sensinact.gateway.common.primitive.Modifiable;
import org.eclipse.sensinact.gateway.common.primitive.PrimitiveDescription;

/**
 * {@link Description} of a {@link Metadata}
 * 
 * @author <a href="mailto:christophe.munilla@cea.fr">Christophe Munilla</a>
 */
public class MetadataDescription extends PrimitiveDescription {
	private static final String EMPTY = "";

	/**
	 * Constructor
	 * 
	 * @param metadata
	 *            the {@link Metadata} for which to instantiate the
	 *            MetadataDescription
	 */
	public MetadataDescription(Metadata metadata) {
		super(metadata);
	}

	/**
	 * @inheritDoc
	 * 
	 * @see Description #getJSONDescription()
	 */
	@Override
	public String getJSONDescription() {
		JSONObject description = this.getJSONObjectDescription();
		if (description == null) {
			return EMPTY;
		}
		return description.toString();
	}

	/**
	 * Returns the JSON object representation of the described {@link Metadata}
	 * 
	 * @return the JSON object representation of the described {@link Metadata}
	 */
	protected JSONObject getJSONObjectDescription() {
		if (Modifiable.FIXED.equals(super.modifiable)) {
			JSONObject description = super.getJSONObject();
			description.put(VALUE_KEY, PrimitiveDescription.toJson(this.getType(), this.getValue()));
			return description;
		}
		return null;
	}
}