D-Net

package eu.dnetlib.oai.core;

import java.util.List;

import eu.dnetlib.oai.CannotDisseminateFormatException;

import eu.dnetlib.oai.conf.OAIConfigurationExistReader;

import eu.dnetlib.oai.conf.OAIISLookUpClient;

import eu.dnetlib.oai.info.*;

import eu.dnetlib.oai.sets.SetCollection;

import eu.dnetlib.rmi.provision.MDFInfo;

import eu.dnetlib.rmi.provision.OaiPublisherException;

import net.sf.ehcache.Cache;

import net.sf.ehcache.Element;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

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

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

/**

 * Core OAI servlet implementation.

 *

 * @author michele, alessia

 */

public abstract class AbstractOAICore {

	private static final Log log = LogFactory.getLog(AbstractOAICore.class); // NOPMD by marko on 11/24/08 5:02 PM

	/**

	 * page size.

	 */

	protected int pageSize = 100;

	private String currentDBName;

	@Autowired

	private SetCollection setCollection;

	@Autowired

	private OAIConfigurationExistReader oaiConfigurationExistReader;

	@Autowired

	private OAIISLookUpClient lookupClient;

	private Cache mdFormatsCache;

	/**

	 * Returns informations about a record. It contains basic information about a record, such as "prefix", "identifier", "datestamp",

	 * "setspec", "metadata".

	 *

	 * @param identifier record identifier

	 * @param prefix     metadata prefix

	 * @return a recordInfo instance

	 * @throws OaiPublisherException could happen

	 */

	public RecordInfo getInfoRecord(final String identifier, final String prefix) throws OaiPublisherException {

		MDFInfo mdf = obtainMDFInfo(prefix);

		return getRecordById(mdf, identifier);

	}

	/**

	 * List records.

	 *

	 * @param onlyIdentifiers only return record identifiers

	 * @param metadataPrefix  metadata prefix

	 * @param set             set name

	 * @param from            from date

	 * @param until           to date

	 * @return ListRecordsInfo

	 * @throws OaiPublisherException could happen

	 */

	public ListRecordsInfo listRecords(final boolean onlyIdentifiers, final String metadataPrefix, final String set, final String from, final String until)

			throws OaiPublisherException {

		final ListRecordsInfo res = new ListRecordsInfo();

		if (from != null) {

			res.setFrom(from);

			res.setWithSize(false);

		}

		if (until != null) {

			res.setUntil(until);

			res.setWithSize(false);

		}

		if (metadataPrefix != null) {

			res.setMetadataprefix(metadataPrefix);

		}

		if (set != null) {

			res.setSet(set);

		}

		ListDocumentsInfo documents = getDocuments(onlyIdentifiers, set, metadataPrefix, from, until);

		ResumptionToken resumptionToken = documents.getResumptionToken();

		int cursor = documents.getCursor();

		int nMaxElements = documents.getnMaxElements();

		if (onlyIdentifiers) {

			res.setIdentifiers(documents.getDocs());

		} else {

			res.setDocuments(documents.getDocs());

		}

		if ((resumptionToken != null)) {

			res.setResumptiontoken(resumptionToken.serialize());

			res.setCursor(cursor);

			res.setSize(nMaxElements);

		}

		return res;

	}

	/**

	 * List records.

	 *

	 * @param onlyIdentifiers only resource identifiers.

	 * @param resumptionToken resumption token

	 * @return ListRecordsInfo

	 * @throws OaiPublisherException could happen

	 */

	public ListRecordsInfo listRecords(final boolean onlyIdentifiers, final String resumptionToken) throws OaiPublisherException {

		ListDocumentsInfo docs = getDocuments(onlyIdentifiers, resumptionToken);

		final ListRecordsInfo res = new ListRecordsInfo();

		if (docs.getMetadataPrefix() != null) {

			res.setMetadataprefix(docs.getMetadataPrefix());

		}

		if (onlyIdentifiers) {

			res.setIdentifiers(docs.getDocs());

		} else {

			res.setDocuments(docs.getDocs());

		}

		ResumptionToken newResumptionToken = docs.getResumptionToken();

		if ((newResumptionToken != null)) {

			res.setResumptiontoken(newResumptionToken.serialize());

			res.setCursor(docs.getCursor());

			res.setSize(docs.getnMaxElements());

			res.setWithSize(!newResumptionToken.hasDateRange());

		}

		return res;

	}

	public List<? extends SetInfo> listSets() throws OaiPublisherException {

		return this.setCollection.getAllSets(true, getCurrentDBName());

	}

	public List<MDFInfo> listMetadataFormats() throws OaiPublisherException {

		return this.oaiConfigurationExistReader.getMetadataFormatInfo(true);

	}

	public boolean existSet(final String setSpec) {

		return this.setCollection.containEnabledSet(setSpec, getCurrentDBName());

	}

	protected MDFInfo obtainMDFInfo(final String metadataPrefix) throws OaiPublisherException {

		MDFInfo mdf = null;

		final Element element = this.mdFormatsCache.get(metadataPrefix);

		if (element == null) {

			log.fatal("Not using cache for " + metadataPrefix);

			mdf = oaiConfigurationExistReader.getMetadataFormatInfo(metadataPrefix);

			if (mdf == null) throw new CannotDisseminateFormatException("Invalid metadataPrefix " + metadataPrefix);

			this.mdFormatsCache.put(new Element(metadataPrefix, mdf));

		} else {

			mdf = (MDFInfo) element.getObjectValue();

		}

		return mdf;

	}

	/**

	 * Set the current DB from the configuration on the IS.

	 */

	public void setCurrentDBFromIS() throws OaiPublisherException {

		try {

			currentDBName = getLookupClient().getCurrentDB();

		} catch (Exception e) {

			throw new OaiPublisherException(e);

		}

	}

	protected abstract RecordInfo getRecordById(final MDFInfo mdf, final String id) throws OaiPublisherException;

	protected abstract ListDocumentsInfo getDocuments(final boolean onlyIdentifiers,

			final String set,

			final String metadataPrefix,

			final String from,

			final String until) throws OaiPublisherException;

	protected abstract ListDocumentsInfo getDocuments(final boolean onlyIdentifiers, final String resumptionToken) throws OaiPublisherException;

	public String getCurrentDBName() {

		return currentDBName;

	}

	public void setCurrentDBName(final String currentDBName) {

		this.currentDBName = currentDBName;

	}

	public SetCollection getSetCollection() {

		return setCollection;

	}

	public void setSetCollection(final SetCollection setCollection) {

		this.setCollection = setCollection;

	}

	public OAIConfigurationExistReader getOaiConfigurationExistReader() {

		return oaiConfigurationExistReader;

	}

	public void setOaiConfigurationExistReader(final OAIConfigurationExistReader oaiConfigurationExistReader) {

		this.oaiConfigurationExistReader = oaiConfigurationExistReader;

	}

	public OAIISLookUpClient getLookupClient() {

		return lookupClient;

	}

	public void setLookupClient(final OAIISLookUpClient lookupClient) {

		this.lookupClient = lookupClient;

	}

	public Cache getMdFormatsCache() {

		return mdFormatsCache;

	}

	@Required

	public void setMdFormatsCache(final Cache mdFormatsCache) {

		this.mdFormatsCache = mdFormatsCache;

	}

}