D-Net

package eu.dnetlib.data.objectstore.modular.gridFS;

import java.util.ArrayList;

import java.util.List;

import java.util.Set;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import com.google.common.collect.Lists;

import com.mongodb.BasicDBObject;

import com.mongodb.DBCursor;

import com.mongodb.DBObject;

import com.mongodb.QueryBuilder;

import com.mongodb.gridfs.GridFS;

import com.mongodb.gridfs.GridFSDBFile;

import eu.dnetlib.enabling.resultset.ResultSet;

import eu.dnetlib.enabling.resultset.ResultSetAware;

import eu.dnetlib.enabling.resultset.ResultSetListener;

import eu.dnetlib.miscutils.collections.MappedCollection;

/**

 * The listener interface for receiving gridFSObjectstoreResultSet events. The class that is interested in processing a

 * gridFSObjectstoreResultSet event implements this interface, and the object created with that class is registered with a component using

 * the component's <code>addGridFSObjectstoreResultSetListener<code> method. When the gridFSObjectstoreResultSet event occurs, that object's

 * appropriate method is invoked.

 *

 * @see GridFSObjectstoreResultSetEvent

 */

public class GridFSObjectstoreResultSetListener implements ResultSetListener, ResultSetAware {

	/** The Constant log. */

	private static final Log log = LogFactory.getLog(GridFSObjectstoreResultSetListener.class);

	/** The from date. */

	private Long fromDate;

	/** The until date. */

	private Long untilDate;

	/** The records. */

	private List<String> records;

	/** The object store id. */

	private String objectStoreID;

	/** The collection. */

	private GridFS collection;

	/** The base uri. */

	private String baseURI;

	/** The current size. */

	private int currentSize = -1;

	/** The current cursor. */

	private DBCursor currentCursor;

	/** The cursor position. */

	private long cursorPosition;

	/** The tags. */

	private Set<String> tags;

	/*

	 * (non-Javadoc)

	 *

	 * @see eu.dnetlib.enabling.resultset.TypedResultSetListener#getResult(int, int)

	 */

	@Override

	public List<String> getResult(final int from, final int to) {

		log.debug(String.format("ObjectStoreId :%s, from: %d, to: %d", objectStoreID, from, to));

		if (records != null) {

			List<String> ids = Lists.newArrayList();

			for (int i = from; i < to; i++) {

				ids.add(records.get(i));

			}

			QueryBuilder qBuilder = QueryBuilder.start("metadata.id").in(ids);

			DBObject q = qBuilder.get();

			List<GridFSDBFile> out = collection.find(q);

			return MappedCollection.listMap(out, ObjectStoreFileUtility.asJSON(baseURI, objectStoreID));

		} else if (tags != null && !tags.isEmpty()) {

			if (currentCursor == null || cursorPosition > from) {

				createCurrentCursor(this.tags);

			}

			while (cursorPosition < from) {

				currentCursor.next();

				cursorPosition++;

			}

			ArrayList<GridFSDBFile> out = new ArrayList<GridFSDBFile>();

			for (int i = from; i <= to; i++) {

				if (currentCursor.hasNext()) {

					out.add((GridFSDBFile) currentCursor.next());

					cursorPosition++;

				}

			}

			return MappedCollection.listMap(out, ObjectStoreFileUtility.asJSON(baseURI, objectStoreID));

		}

		else if (fromDate != null && untilDate != null) {

			if (currentCursor == null || cursorPosition > from) {

				createCurrentCursor();

			}

			while (cursorPosition < from) {

				currentCursor.next();

				cursorPosition++;

			}

			ArrayList<GridFSDBFile> out = new ArrayList<GridFSDBFile>();

			for (int i = from; i <= to; i++) {

				if (currentCursor.hasNext()) {

					out.add((GridFSDBFile) currentCursor.next());

					cursorPosition++;

				}

			}

			return MappedCollection.listMap(out, ObjectStoreFileUtility.asJSON(baseURI, objectStoreID));

		}

		throw new IllegalArgumentException("Missing parameters on Delivery must provide either from, to, or ObjectStoreIDs");

	}

	/**

	 * Creates the current cursor.

	 */

	private void createCurrentCursor(final Set<String> tags) {

		QueryBuilder qBuilder = QueryBuilder.start("metadata.tags").in(tags);

		if (currentCursor != null) {

			currentCursor.close();

		}

		currentCursor = collection.getFileList(qBuilder.get()).sort(new BasicDBObject("_id", 1));

		cursorPosition = 1;

	}

	/**

	 * Creates the current cursor.

	 */

	private void createCurrentCursor() {

		BasicDBObject query = new BasicDBObject();

		query.put("$gt", fromDate.doubleValue());

		query.put("$lt", untilDate.doubleValue());

		if (currentCursor != null) {

			currentCursor.close();

		}

		currentCursor = collection.getFileList(new BasicDBObject("metadata.timestamp", query)).sort(new BasicDBObject("_id", 1));

		cursorPosition = 1;

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see eu.dnetlib.enabling.resultset.TypedResultSetListener#getSize()

	 */

	@Override

	public int getSize() {

		if (currentSize == -1) {

			currentSize = calculateSize();

		}

		return currentSize;

	}

	/**

	 * Calculate size.

	 *

	 * @return the int

	 */

	private int calculateSize() {

		if (records != null) {

			QueryBuilder qBuilder = QueryBuilder.start("metadata.id").in(records);

			DBObject q = qBuilder.get();

			List<GridFSDBFile> out = collection.find(q);

			return out.size();

		} else if (fromDate != null && untilDate != null) {

			BasicDBObject query = new BasicDBObject();

			query.put("$gt", fromDate.doubleValue());

			query.put("$lt", untilDate.doubleValue());

			return collection.getFileList(new BasicDBObject("metadata.timestamp", query)).size();

		} else if (tags != null) {

			QueryBuilder qBuilder = QueryBuilder.start("metadata.tags").in(tags);

			DBObject q = qBuilder.get();

			List<GridFSDBFile> out = collection.find(q);

			return out.size();

		}

		return 0;

	}

	/*

	 * (non-Javadoc)

	 *

	 * @see eu.dnetlib.enabling.resultset.ResultSetAware#setResultSet(eu.dnetlib.enabling.resultset.ResultSet)

	 */

	@Override

	public void setResultSet(final ResultSet resultSet) {

		resultSet.close();

	}

	/**

	 * Gets the from date.

	 *

	 * @return the from date

	 */

	public Long getFromDate() {

		return fromDate;

	}

	/**

	 * Sets the from date.

	 *

	 * @param fromdate

	 *            the new from date

	 */

	public void setFromDate(final Long fromdate) {

		this.fromDate = fromdate;

	}

	/**

	 * Gets the until date.

	 *

	 * @return the until date

	 */

	public Long getUntilDate() {

		return untilDate;

	}

	/**

	 * Sets the until date.

	 *

	 * @param untilDate

	 *            the new until date

	 */

	public void setUntilDate(final Long untilDate) {

		this.untilDate = untilDate;

	}

	/**

	 * Gets the records.

	 *

	 * @return the records

	 */

	public List<String> getRecords() {

		return records;

	}

	/**

	 * Sets the records.

	 *

	 * @param records

	 *            the new records

	 */

	public void setRecords(final List<String> records) {

		this.records = records;

	}

	/**

	 * Gets the collection.

	 *

	 * @return the collection

	 */

	public GridFS getCollection() {

		return collection;

	}

	/**

	 * Sets the collection.

	 *

	 * @param collection

	 *            the new collection

	 */

	public void setCollection(final GridFS collection) {

		this.collection = collection;

	}

	/**

	 * Gets the base uri.

	 *

	 * @return the base uri

	 */

	public String getBaseURI() {

		return baseURI;

	}

	/**

	 * Sets the base uri.

	 *

	 * @param baseURI

	 *            the new base uri

	 */

	public void setBaseURI(final String baseURI) {

		this.baseURI = baseURI;

	}

	/**

	 * Gets the object store id.

	 *

	 * @return the object store id

	 */

	public String getObjectStoreID() {

		return objectStoreID;

	}

	/**

	 * Sets the object store id.

	 *

	 * @param objectStoreID

	 *            the new object store id

	 */

	public void setObjectStoreID(final String objectStoreID) {

		this.objectStoreID = objectStoreID;

	}

	/**

	 * @return the tags

	 */

	public Set<String> getTags() {

		return tags;

	}

	/**

	 * @param tags

	 *            the tags to set

	 */

	public void setTags(final Set<String> tags) {

		this.tags = tags;

	}

}