D-Net

package eu.dnetlib.enabling.tools.blackboard;

import java.util.Map;

import javax.xml.bind.JAXBException;

import javax.xml.transform.dom.DOMSource;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

import org.springframework.beans.factory.annotation.Required;

import org.w3c.dom.Element;

import eu.dnetlib.enabling.is.registry.rmi.ISRegistryException;

import eu.dnetlib.enabling.is.registry.rmi.ISRegistryService;

import eu.dnetlib.enabling.locators.UniqueServiceLocator;

import eu.dnetlib.enabling.tools.OpaqueResource;

import eu.dnetlib.enabling.tools.UniqueIdentifierGenerator;

import eu.dnetlib.enabling.tools.UniqueIdentifierGeneratorImpl;

import eu.dnetlib.miscutils.jaxb.JaxbFactory;

/**

 * Blackboard client.

 * 

 * @author marko

 * 

 */

public class BlackboardClientHandlerImpl implements BlackboardClientHandler {

	/**

	 * blackboard message factory.

	 */

	private JaxbFactory<BlackboardMessage> messageFactory;

	/**

	 * service locator.

	 */

	private UniqueServiceLocator serviceLocator;

	/**

	 * generates blackboard message identifiers for new jobs.

	 */

	private UniqueIdentifierGenerator uuidGenerator = new UniqueIdentifierGeneratorImpl("bb-");

	/**

	 * {@inheritDoc}

	 * 

	 * @see eu.dnetlib.enabling.tools.blackboard.BlackboardClientHandler#assign(eu.dnetlib.enabling.tools.blackboard.BlackboardJob)

	 */

	@Override

	public void assign(final BlackboardJob job) {

		checkJob(job);

		try {

			serviceLocator.getService(ISRegistryService.class).addBlackBoardMessage(job.getServiceId(), job.getId(),

					messageFactory.serialize(job.getMessage()));

		} catch (final ISRegistryException e) {

			throw new IllegalStateException("cannot register blackboard message", e);

		} catch (final JAXBException e) {

			throw new IllegalArgumentException("cannot serialize blackboard message", e);

		}

	}

	/**

	 * Check that the job has sane values.

	 * 

	 * @param job

	 */

	protected void checkJob(final BlackboardJob job) {

		for (Map.Entry<String, String> param : job.getParameters().entrySet()) {

			if (param.getValue() == null) { throw new IllegalStateException("job parameter value cannot be null: " + param.getKey()); }

		}

	}

	/**

	 * {@inheritDoc}

	 * 

	 * @see eu.dnetlib.enabling.tools.blackboard.BlackboardClientHandler#delete(eu.dnetlib.enabling.tools.blackboard.BlackboardJob)

	 */

	@Override

	public void delete(final BlackboardJob job) {

		try {

			serviceLocator.getService(ISRegistryService.class).deleteBlackBoardMessage(job.getServiceId(), job.getId());

		} catch (final ISRegistryException e) {

			throw new IllegalStateException("cannot delete blackboard message", e);

		}

	}

	/**

	 * {@inheritDoc}

	 * 

	 * @see eu.dnetlib.enabling.tools.blackboard.BlackboardClientHandler#newJob()

	 */

	@Override

	public BlackboardJob newJob(final String serviceId) {

		final BlackboardJob job = new BlackboardJobImpl(serviceId, messageFactory.newInstance());

		job.setActionStatus(ActionStatus.ASSIGNED);

		job.getParameters().put("id", "");

		job.getParameters().put("error", "");

		job.setId(uuidGenerator.generateIdentifier());

		return job;

	}

	/**

	 * {@inheritDoc}

	 * 

	 * @see eu.dnetlib.enabling.tools.blackboard.BlackboardHandler#getJob(eu.dnetlib.enabling.tools.OpaqueResource)

	 */

	@Override

	public BlackboardJob getJob(final OpaqueResource profile) {

		final XPath xpa = XPathFactory.newInstance().newXPath();

		try {

			final Element source = (Element) xpa.evaluate("/RESOURCE_PROFILE/BODY/BLACKBOARD/MESSAGE[@id = /RESOURCE_PROFILE/BODY/BLACKBOARD/LAST_RESPONSE]",

					profile.asDom(), XPathConstants.NODE);

			if (source == null) { throw new IllegalStateException("cannot find last blackboard message in the service profile"); }

			return new BlackboardJobImpl(profile.getResourceId(), messageFactory.parse(new DOMSource(source)));

		} catch (final JAXBException e) {

			throw new IllegalStateException("cannot parse blackboard message", e);

		} catch (final XPathExpressionException e) {

			throw new IllegalStateException("cannot find last blackboard message in the service profile", e);

		}

	}

	public JaxbFactory<BlackboardMessage> getMessageFactory() {

		return messageFactory;

	}

	public void setMessageFactory(final JaxbFactory<BlackboardMessage> messageFactory) {

		this.messageFactory = messageFactory;

	}

	public UniqueIdentifierGenerator getUuidGenerator() {

		return uuidGenerator;

	}

	public void setUuidGenerator(final UniqueIdentifierGenerator uuidGenerator) {

		this.uuidGenerator = uuidGenerator;

	}

	public UniqueServiceLocator getServiceLocator() {

		return serviceLocator;

	}

	@Required

	public void setServiceLocator(final UniqueServiceLocator serviceLocator) {

		this.serviceLocator = serviceLocator;

	}

}