76. Datum Data Source¶

The DatumDataSource API defines the primary way for plugins to generate datum instances from devices or services integrated with SolarNode, through a request-based API. The MultiDatumDataSource API is closely related, and allows a plugin to generate multiple datum when requested.

DatumDataSourceMultiDatumDataSource

package net.solarnetwork.node.service;

import net.solarnetwork.node.domain.datum.NodeDatum;
import net.solarnetwork.service.Identifiable;

/**
 * API for collecting {@link NodeDatum} objects from some device.
 */
public interface DatumDataSource extends Identifiable, DeviceInfoProvider {

    /**
     * Get the class supported by this DataSource.
     *
     * @return class
     */
    Class<? extends NodeDatum> getDatumType();

    /**
     * Read the current value from the data source, returning as an unpersisted
     * {@link NodeDatum} object.
     *
     * @return Datum
     */
    NodeDatum readCurrentDatum();

}

package net.solarnetwork.node.service;

import java.util.Collection;
import net.solarnetwork.node.domain.datum.NodeDatum;
import net.solarnetwork.service.Identifiable;

/**
 * API for collecting multiple {@link NodeDatum} objects from some device.
 */
public interface MultiDatumDataSource extends Identifiable, DeviceInfoProvider {

    /**
     * Get the class supported by this DataSource.
     *
     * @return class
     */
    Class<? extends NodeDatum> getMultiDatumType();

    /**
     * Read multiple values from the data source, returning as a collection of
     * unpersisted {@link NodeDatum} objects.
     *
     * @return Datum
     */
    Collection<NodeDatum> readMultipleDatum();

}

The Datum Data Source Poll Job provides a way to let users schedule the polling for datum from a data source.