HistoryEvents.java

//Dstl (c) Crown Copyright 2017
package uk.gov.dstl.baleen.core.history;

import com.google.common.collect.ImmutableMap;

/**
 * This helper utility allows the core history events to be created in a type
 * safe manner.
 *
 * 
 *
 */
public class HistoryEvents {

	public static final String ADDED_TYPE = "added";
	public static final String MERGED_TYPE = "merged";
	public static final String REMOVED_TYPE = "removed";

	public static final String PARAM_MERGED_ID = "mergedId";

	private HistoryEvents() {

	}

	/**
	 * Create a history event which represents a merge.
	 *
	 * @param timestamp
	 *            the timestamp of the merge
	 * @param recordable
	 *            the recordable which was remains
	 * @param referrer
	 *            the object which merged the entities
	 * @param mergedId
	 *            the item which was merged into the recordable
	 */
	public static HistoryEvent createMerged(long timestamp, Recordable recordable, String referrer, long mergedId) {
		return new RecordableHistoryEvent(MERGED_TYPE, timestamp, recordable, referrer, String.format("merged [%d]",
				mergedId), ImmutableMap.of(PARAM_MERGED_ID, Long.toString(mergedId)));
	}

	/**
	 * /** Create a history event which represents a merge, with a specific
	 * time.
	 *
	 * @param recordable
	 *            the recordable which was remains
	 * @param referrer
	 *            the object which merged the entities
	 * @param mergedId
	 *            the item which was merged into the recordable
	 * @return
	 */
	public static HistoryEvent createMerged(Recordable recordable, String referrer, long mergedId) {
		return createMerged(System.currentTimeMillis(), recordable, referrer, mergedId);
	}

	/**
	 * New history signifying the addition of a recordable, with timestamp.
	 *
	 * @param timestamp
	 *            the time of creation
	 * @param recordable
	 *            the created recordable
	 * @param referrer
	 *            the object which performed the action
	 */
	public static HistoryEvent createAdded(long timestamp, Recordable recordable, String referrer) {
		return new RecordableHistoryEvent(ADDED_TYPE, timestamp, recordable, referrer, "added");
	}

	/**
	 * New history signifying the addition of a recordable, with now as the
	 * timestamp.
	 *
	 * @param recordable
	 *            the created recordable
	 * @param referrer
	 *            the object which performed the action
	 */
	public static HistoryEvent createAdded(Recordable recordable, String referrer) {
		return createAdded(System.currentTimeMillis(), recordable, referrer);
	}

	/**
	 * New history signifying the removal/deletion of a recordable, with
	 * timestamp.
	 *
	 * @param timestamp
	 *            the timestamp of the event
	 * @param recordable
	 *            the recordable which was removed
	 * @param referrer
	 *            the object which removed the recordable
	 */
	public static HistoryEvent createRemoved(long timestamp, Recordable recordable, String referrer) {
		return new RecordableHistoryEvent(REMOVED_TYPE, timestamp, recordable, referrer, "removed");
	}

	/**
	 * New history signifying the removal/deletion of a recordable, with now as
	 * timestamp. *
	 *
	 * @param recordable
	 *            the recordable which was removed
	 * @param referrer
	 *            the object which removed the recordable
	 */
	public static HistoryEvent createRemoved(Recordable recordable, String referrer) {
		return createRemoved(System.currentTimeMillis(), recordable, referrer);
	}
}