Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class that gets Accession Number, check for uniqueness

 *             and register it into db

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova, Matt Jones

 *

 *   '$Author: leinfelder $'

 *     '$Date: 2011-11-02 20:40:12 -0700 (Wed, 02 Nov 2011) $'

 * '$Revision: 6595 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.index;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Calendar;

import java.util.Collections;

import java.util.Date;

import java.util.List;

import java.util.TimerTask;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPathExpressionException;

import org.apache.commons.io.FileUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.apache.solr.client.solrj.SolrServerException;

import org.dataone.configuration.Settings;

import org.dataone.service.exceptions.InvalidRequest;

import org.dataone.service.exceptions.InvalidToken;

import org.dataone.service.exceptions.NotAuthorized;

import org.dataone.service.exceptions.NotFound;

import org.dataone.service.exceptions.NotImplemented;

import org.dataone.service.exceptions.ServiceFailure;

import org.dataone.service.exceptions.UnsupportedType;

import org.dataone.service.types.v1.Event;

import org.dataone.service.types.v1.Identifier;

import org.dataone.service.types.v1.ObjectFormatIdentifier;

import org.dataone.service.types.v1.SystemMetadata;

import org.xml.sax.SAXException;

import com.hazelcast.core.IMap;

import com.hazelcast.core.ISet;

import edu.ucsb.nceas.metacat.common.SolrServerFactory;

import edu.ucsb.nceas.metacat.common.index.event.IndexEvent;

import edu.ucsb.nceas.metacat.index.event.EventlogFactory;

import edu.ucsb.nceas.metacat.index.event.IndexEventLogException;

/**

 * A class represents the object to generate massive solr indexes.

 * This can happen during an update of Metacat (generating index for all existing documents)

 * or regenerate index for those documents

 * failing to build index during the insert or update.

 * 

 * @author tao

 *

 */

public class IndexGenerator extends TimerTask {

    private static final int FIRST =0;

    private static final int SECOND =1;

    private static final int THIRD = 2;

    private static final int FOURTH = 3;

    public static final int WAITTIME = 10000;

    public static final int MAXWAITNUMBER = 180;

    private static final String HTTP = "http://";

    private static final String MNAPPENDIX = "/d1/mn";

    private static final String RESOURCEMAPPROPERYNAME = "index.resourcemap.namespace";

    public static final String WAITIMEPOPERTYNAME = "index.regenerate.start.waitingtime";

    public static final String MAXATTEMPTSPROPERTYNAME = "index.regenerate.start.maxattempts";

    private static int waitingTime = WAITTIME;

    private static int maxAttempts = MAXWAITNUMBER;

    private SolrIndex solrIndex = null;

    //private SystemMetadataEventListener systemMetadataListener = null;

    private IMap<Identifier, SystemMetadata> systemMetadataMap;

    private IMap<Identifier, String> objectPathMap;

    private Log log = LogFactory.getLog(IndexGenerator.class);

    //private MNode mNode = null;

    private static List<String> resourceMapNamespaces = null;

    /**

     * Constructor

     * @param solrIndex

     * @param systemMetadataListener

     */

    public IndexGenerator(SolrIndex solrIndex) {

        this.solrIndex = solrIndex;

        resourceMapNamespaces = Settings.getConfiguration().getList(RESOURCEMAPPROPERYNAME);

        //this.systemMetadataListener = systemMetadataListener;

        //this.mNode = new MNode(buildMNBaseURL());

        try {

            waitingTime = Settings.getConfiguration().getInt(WAITIMEPOPERTYNAME);

            maxAttempts = Settings.getConfiguration().getInt(MAXATTEMPTSPROPERTYNAME);

        } catch (Exception e) {

            log.warn("IndexGenerator.constructor - couldn't read the waiting time or maxattempts from the metacat.properties file since : "+e.getMessage()+". Default values will be used");

            waitingTime = WAITTIME;

            maxAttempts = MAXWAITNUMBER;

        }

    }

    /**

     * Build the index for all documents in Metacat without overwriting.

     * @throws SolrServerException 

     * @throws ServiceFailure 

     * @throws NotImplemented 

     * @throws NotAuthorized 

     * @throws InvalidToken 

     * @throws InvalidRequest 

     * @throws IndexEventLogException 

     * @throws IllegalAccessException 

     * @throws InstantiationException 

     * @throws ClassNotFoundException 

     */

    /*public void indexAll() throws InvalidRequest, InvalidToken, NotAuthorized, 

                            NotImplemented, ServiceFailure, SolrServerException, FileNotFoundException, ClassNotFoundException, InstantiationException, IllegalAccessException, IndexEventLogException {

        boolean force = false;

        indexAll(force);

    }*/

    /**

     * Build the index for all documents.

     * @throws SolrServerException 

     * @throws ServiceFailure 

     * @throws NotImplemented 

     * @throws NotAuthorized 

     * @throws InvalidToken 

     * @throws InvalidRequest 

     * @throws IndexEventLogException 

     * @throws IllegalAccessException 

     * @throws InstantiationException 

     * @throws ClassNotFoundException 

     * @throws ParserConfigurationException 

     * @throws SAXException 

     * @throws IOException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws XPathExpressionException 

     */

    public void indexAll() throws InvalidRequest, InvalidToken,

                NotAuthorized, NotImplemented, ServiceFailure, SolrServerException, ClassNotFoundException, InstantiationException, IllegalAccessException, IndexEventLogException, XPathExpressionException, NotFound, UnsupportedType, IOException, SAXException, ParserConfigurationException {

        Date since = null;

        Date until = null;

        index(since, until);

    }

    /**

     * Build the index for the docs which have been modified since the specified date.

     * @param since

     * @throws SolrServerException 

     * @throws ServiceFailure 

     * @throws NotImplemented 

     * @throws NotAuthorized 

     * @throws InvalidToken 

     * @throws InvalidRequest 

     * @throws IndexEventLogException 

     * @throws IllegalAccessException 

     * @throws InstantiationException 

     * @throws ClassNotFoundException 

     * @throws ParserConfigurationException 

     * @throws SAXException 

     * @throws IOException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws XPathExpressionException 

     */

    public void index(Date since) throws InvalidRequest, InvalidToken, 

                    NotAuthorized, NotImplemented, ServiceFailure, SolrServerException, ClassNotFoundException, InstantiationException, IllegalAccessException, IndexEventLogException, XPathExpressionException, NotFound, UnsupportedType, IOException, SAXException, ParserConfigurationException {

        Date until = null;

        index(since, until);

    }

    /**

     *  Build the index for the docs which have been modified between the specified date.s

     * @param since

     * @param until

     * @throws SolrServerException 

     * @throws ServiceFailure 

     * @throws NotImplemented 

     * @throws NotAuthorized 

     * @throws InvalidToken 

     * @throws InvalidRequest 

     * @throws IndexEventLogException 

     * @throws IllegalAccessException 

     * @throws InstantiationException 

     * @throws ClassNotFoundException 

     * @throws ParserConfigurationException 

     * @throws SAXException 

     * @throws IOException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws XPathExpressionException 

     */

    public void index(Date since, Date until) throws SolrServerException, InvalidRequest, 

                                                InvalidToken, NotAuthorized, NotImplemented, ServiceFailure, ClassNotFoundException, InstantiationException, IllegalAccessException, IndexEventLogException, XPathExpressionException, NotFound, UnsupportedType, IOException, SAXException, ParserConfigurationException {

        Date processedDate = null;

        List<String> solrIds = null;

        initSystemMetadataMap();

        initObjectPathMap();

        List[] metacatIds = getMetacatIds(since, until);

        List<String> otherMetacatIds = metacatIds[FIRST];

        List<String> resourceMapIds =  metacatIds[SECOND];

        List<String> otherDeletedMetacatIds = metacatIds[THIRD];

        List<String> resourceMapDeletedIds = metacatIds[FOURTH];

        //figure out the procesedDate by comparing the last element of otherMetacatIds and resourceMapIds.

        List<Long> maxCollection = new ArrayList<Long>();

        Date latestOtherId = null;

        if (otherMetacatIds != null && !otherMetacatIds.isEmpty()) {

            int size = otherMetacatIds.size();

            String id = otherMetacatIds.get(size-1);

            SystemMetadata sysmeta = getSystemMetadata(id);

            latestOtherId = sysmeta.getDateSysMetadataModified();

            maxCollection.add(new Long(latestOtherId.getTime()));

        }

        Date latestDeletedOtherIds = null;

        if (otherDeletedMetacatIds != null && !otherDeletedMetacatIds.isEmpty()) {

            int size = otherDeletedMetacatIds.size();

            String id = otherDeletedMetacatIds.get(size-1);

            SystemMetadata sysmeta = getSystemMetadata(id);

            latestDeletedOtherIds = sysmeta.getDateSysMetadataModified();

            maxCollection.add(new Long(latestDeletedOtherIds.getTime()));

        }

        Date latestResourceId = null;

        if (resourceMapIds != null && !resourceMapIds.isEmpty()) {

            int size = resourceMapIds.size();

            String id = resourceMapIds.get(size-1);

            SystemMetadata sysmeta = getSystemMetadata(id);

            latestResourceId = sysmeta.getDateSysMetadataModified();

            maxCollection.add(new Long(latestResourceId.getTime()));

        }

        Date latestDeletedResourceId = null;

        if(resourceMapDeletedIds != null && !resourceMapDeletedIds.isEmpty()) {

            int size = resourceMapDeletedIds.size();

            String id = resourceMapDeletedIds.get(size-1);

            SystemMetadata sysmeta = getSystemMetadata(id);

            latestDeletedResourceId = sysmeta.getDateSysMetadataModified();

            maxCollection.add(new Long(latestDeletedResourceId.getTime()));

        }

        if(!maxCollection.isEmpty()) {

            Long max = Collections.max(maxCollection);

            processedDate = new Date(max.longValue());

        }

        /*if(latestOtherId != null && latestResourceId != null && latestOtherId.getTime() > latestResourceId.getTime()) {

            processedDate = latestOtherId;

        } else if (latestOtherId != null && latestResourceId != null && latestOtherId.getTime()  <= latestResourceId.getTime()) {

            processedDate = latestResourceId;

        } else if (latestOtherId == null && latestResourceId != null) {

            processedDate = latestResourceId;

        } else if (latestOtherId != null && latestResourceId == null) {

            processedDate = latestOtherId;

        }*/

        //add the failedPids 

        List<IndexEvent> failedEvents = EventlogFactory.createIndexEventLog().getEvents(null, null, null, null);

        List<IndexEvent> failedOtherIds = new ArrayList<IndexEvent>();

        List<IndexEvent> failedResourceMapIds = new ArrayList<IndexEvent>();

        if(failedEvents != null) {

            for(IndexEvent event : failedEvents) {

            	String id = event.getIdentifier().getValue();

                SystemMetadata sysmeta = getSystemMetadata(id);

                if(sysmeta != null) {

                    ObjectFormatIdentifier formatId =sysmeta.getFormatId();

                    if(formatId != null && formatId.getValue() != null && resourceMapNamespaces != null && isResourceMap(formatId)) {

                        failedResourceMapIds.add(event);

                    } else {

                        failedOtherIds.add(event);

                    }

                }

            }

        }

        indexFailedIds(failedOtherIds);

        indexFailedIds(failedResourceMapIds);

        /*if(!failedOtherIds.isEmpty()) {

            failedOtherIds.addAll(otherMetacatIds);

        } else {

            failedOtherIds = otherMetacatIds;

        }

        if(!failedResourceMapIds.isEmpty()) {

            failedResourceMapIds.addAll(resourceMapIds);

        } else {

            failedResourceMapIds = resourceMapIds;

        }*/

        log.info("the metacat ids (except the resource map ids)-----------------------------"+otherMetacatIds);

        logFile(otherMetacatIds);

        log.info("the deleted metacat ids (except the resource map ids)-----------------------------"+otherDeletedMetacatIds);

        log.info("the metacat resroucemap ids -----------------------------"+resourceMapIds);

        logFile(resourceMapIds);

        log.info("the deleted metacat resroucemap ids -----------------------------"+resourceMapDeletedIds);

        index(otherMetacatIds);

        removeIndex(otherDeletedMetacatIds);

        index(resourceMapIds);

        removeIndex(resourceMapDeletedIds);

        //record the timed index.

        if(processedDate != null) {

            EventlogFactory.createIndexEventLog().setLastProcessDate(processedDate);

        }

    }

    /*

     * Write the docids which will be indexed into a file. 

     */

    private void logFile(List<String> ids) throws IOException {

        if(ids != null) {

            String solrHomeDir = Settings.getConfiguration().getString(SolrServerFactory.SOLR_HOME_PROPERTY_NAME);

            File idsForIndex = new File(solrHomeDir, "ids-for-timed-indexing-log");

            if(!idsForIndex.exists()) {

                idsForIndex.createNewFile();

            }

            Date date = Calendar.getInstance().getTime();

            SimpleDateFormat format = new SimpleDateFormat("yyyy.MM.dd G 'at' HH:mm:ss z");

            String dateStr = format.format(date);

            List<String> dateList = new ArrayList<String>();

            dateList.add(dateStr);

            Boolean append = true;

            FileUtils.writeLines(idsForIndex, dateList, append);//write time string

            FileUtils.writeLines(idsForIndex, ids, append);

        }

    }

    /*

     * Doing index

     */

    private void index(List<String> metacatIds) {

        if(metacatIds != null) {

            for(String metacatId : metacatIds) {

                if(metacatId != null) {

                        try {

                            generateIndex(metacatId);

                        } catch (Exception e) {

                            IndexEvent event = new IndexEvent();

                            Identifier pid = new Identifier();

                            pid.setValue(metacatId);

                            event.setIdentifier(pid);

                            event.setDate(Calendar.getInstance().getTime());

                            event.setAction(Event.CREATE);

                            String error = "IndexGenerator.index - Metacat Index couldn't generate the index for the id - "+metacatId+" because "+e.getMessage();

                            event.setDescription(error);

                            try {

                                EventlogFactory.createIndexEventLog().write(event);

                            } catch (Exception ee) {

                                log.error("SolrIndex.insertToIndex - IndexEventLog can't log the index inserting event :"+ee.getMessage());

                            }

                            log.error(error);

                        }

                }

            }

        }

    }

    /*

     * Index those ids which failed in the process (We got them from the EventLog)

     */

    private void indexFailedIds(List<IndexEvent> events) {

        if(events != null) {

            for(IndexEvent event : events) {

                if(event != null) {

                    Identifier identifier = event.getIdentifier();

                    if(identifier != null) {

                        String id = identifier.getValue();

                        if(id != null) {

                            Event action = event.getAction();

                            if (action != null && action.equals(Event.CREATE)) {

                                try {

                                    generateIndex(id);

                                    EventlogFactory.createIndexEventLog().remove(identifier);

                                } catch (Exception e) {

                                    log.error("IndexGenerator.indexFailedIds - Metacat Index couldn't generate the index for the id - "+id+" because "+e.getMessage());

                                }

                            } else if (action != null && action.equals(Event.DELETE)) {

                                try {

                                    removeIndex(id);

                                    EventlogFactory.createIndexEventLog().remove(identifier);

                                } catch (Exception e) {

                                    log.error("IndexGenerator.indexFailedIds - Metacat Index couldn't remove the index for the id - "+id+" because "+e.getMessage());

                                }

                            }

                        }

                    }

                }

            }

        }

    }

    public void run() {

        /*IndexEvent event = new IndexEvent();

        event.setDate(Calendar.getInstance().getTime());

        event.setType(IndexEvent.STARTTIMEDINDEX);

        event.setDescription("Start the timed index job");

        try {

            EventlogFactory.createIndexEventLog().write(event);

        } catch (Exception e) {

            log.error("IndexGenerator.run - IndexEventLog can't log the timed indexing start event :"+e.getMessage());

        }*/

        try {

            Date since = EventlogFactory.createIndexEventLog().getLastProcessDate();

            index(since);

        } catch (InvalidRequest e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (InvalidToken e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (NotAuthorized e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

        } catch (NotImplemented e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (ServiceFailure e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (SolrServerException e) {

            // TODO Auto-generated catch block

            //e.printStackTrace();

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (FileNotFoundException e) {

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        }

        /*event.setDate(Calendar.getInstance().getTime());

        event.setType(IndexEvent.FINISHTIMEDINDEX);

        event.setDescription("Finish the timed index job");

        try {

            EventlogFactory.createIndexEventLog().write(event);

        } catch (Exception e) {

            log.error("IndexGenerator.run - IndexEventLog can't log the timed indexing finish event :"+e.getMessage());

        }*/ catch (ClassNotFoundException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (InstantiationException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (IllegalAccessException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (IndexEventLogException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (XPathExpressionException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (NotFound e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (UnsupportedType e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (IOException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (SAXException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        } catch (ParserConfigurationException e) {

            // TODO Auto-generated catch block

            log.error("IndexGenerator.run - Metadata-Index couldn't generate indexes for those documents which haven't been indexed : "+e.getMessage());

        }

    }

    /*

     * Get the indexed ids list from the solr server.

     * An empty list will be returned if there is no ids.

     */

    private List<String> getSolrDocIds() throws SolrServerException {

        List<String> ids = solrIndex.getSolrIds();

        return ids;

    }

    /*

     * Get an array of the list of ids of the metacat which has the systemmetadata modification in the range.

     * 

     * If since and util are null, it will return all of them.

     * The first element of the list is the ids except the resource map. The second elements of the list is the ids of the resource map.

     * The reason to split them is when we index the resource map, we need the index of the documents in the resource map ready.

     * The last element in the each list has the latest SystemMetadata modification date. But they are not sorted.

     */

    private List[] getMetacatIds(Date since, Date until) throws InvalidRequest, 

                        InvalidToken, NotAuthorized, NotImplemented, ServiceFailure, FileNotFoundException {

        List<String> resourceMapIds = new ArrayList();

        List<String> resourceMapDeletedIds = new ArrayList();

        List<String> otherIds = new ArrayList();

        List<String> otherDeletedIds = new ArrayList();

        List[] ids = new List[4];

        ids[FIRST]= otherIds;

        ids[SECOND] = resourceMapIds;

        ids[THIRD]  = otherDeletedIds;

        ids[FOURTH] = resourceMapDeletedIds;

        ISet<Identifier> metacatIds = DistributedMapsFactory.getIdentifiersSet();

        Date otherPreviousDate = null;

        Date otherDeletedPreviousDate = null;

        Date resourceMapPreviousDate = null;

        Date resourceMapDeletedPreviousDate = null;

        if(metacatIds != null) {

            for(Identifier identifier : metacatIds) {

                if(identifier != null && identifier.getValue() != null && !identifier.getValue().equals("")) {

                    SystemMetadata sysmeta = getSystemMetadata(identifier.getValue());

                    if(sysmeta != null) {

                        ObjectFormatIdentifier formatId =sysmeta.getFormatId();

                        //System.out.println("the object format id is "+formatId.getValue());

                        //System.out.println("the ============ resourcMapNamespaces"+resourceMapNamespaces);

                        boolean correctTimeRange = false;

                        Date sysDate = sysmeta.getDateSysMetadataModified();

                        if(since == null && until == null) {

                            correctTimeRange = true;

                        } else if (since != null && until == null) {

                            if(sysDate.getTime() > since.getTime()) {

                                correctTimeRange = true;

                            }

                        } else if (since == null && until != null) {

                            if(sysDate.getTime() < until.getTime()) {

                                correctTimeRange = true;

                            }

                        } else if (since != null && until != null) {

                            if(sysDate.getTime() > since.getTime() && sysDate.getTime() < until.getTime()) {

                                correctTimeRange = true;

                            }

                        }

                        if(correctTimeRange && formatId != null && formatId.getValue() != null && resourceMapNamespaces != null && isResourceMap(formatId)) {

                            //for the resource map

                            if(sysmeta.getArchived() || sysmeta.getObsoletedBy() != null) {

                                //archived ids

                                if(!resourceMapDeletedIds.isEmpty()) {

                                    if(sysDate.getTime() > resourceMapDeletedPreviousDate.getTime()) {

                                        resourceMapDeletedIds.add(identifier.getValue());//append to the end of the list if current is later than the previous one

                                        resourceMapDeletedPreviousDate = sysDate;//reset resourceMapPreviousDate to the bigger one

                                    } else {

                                        int size = resourceMapDeletedIds.size();//

                                        resourceMapDeletedIds.add(size -1, identifier.getValue());//keep the previous one at the end of the list.

                                    }

                                } else {

                                    resourceMapDeletedIds.add(identifier.getValue());

                                    resourceMapDeletedPreviousDate = sysDate;//init resourcemapPreviousDate

                                }

                            } else {

                                // current ids

                                if(!resourceMapIds.isEmpty()) {

                                    if(sysDate.getTime() > resourceMapPreviousDate.getTime()) {

                                        resourceMapIds.add(identifier.getValue());//append to the end of the list if current is later than the previous one

                                        resourceMapPreviousDate = sysDate;//reset resourceMapPreviousDate to the bigger one

                                    } else {

                                        int size = resourceMapIds.size();//

                                        resourceMapIds.add(size -1, identifier.getValue());//keep the previous one at the end of the list.

                                    }

                                } else {

                                    resourceMapIds.add(identifier.getValue());

                                    resourceMapPreviousDate = sysDate;//init resourcemapPreviousDate

                                }

                            }

                        } else if (correctTimeRange) {

                            if(sysmeta.getArchived() || sysmeta.getObsoletedBy() != null) {

                                //for the archived ids

                                if(!otherDeletedIds.isEmpty()) {

                                    if(sysDate.getTime() > otherDeletedPreviousDate.getTime()) {

                                        otherDeletedIds.add(identifier.getValue());

                                        otherDeletedPreviousDate = sysDate;//reset otherDeletedPreviousDate to the bigger one

                                    } else {

                                        int size = otherDeletedIds.size();

                                        otherDeletedIds.add(size-1, identifier.getValue());

                                    }

                                } else {

                                    otherDeletedIds.add(identifier.getValue());

                                    otherDeletedPreviousDate = sysDate;//init otherDeletedPreviousDate

                                }

                            } else {

                                //for the current ids

                                if(!otherIds.isEmpty()) {

                                    if(sysDate.getTime() > otherPreviousDate.getTime()) {

                                        otherIds.add(identifier.getValue());

                                        otherPreviousDate = sysDate;//reset otherPreviousDate to the bigger one

                                    } else {

                                        int size = otherIds.size();

                                        otherIds.add(size-1, identifier.getValue());

                                    }

                                } else {

                                    otherIds.add(identifier.getValue());

                                    otherPreviousDate = sysDate;//init otherPreviousDate

                                }

                            }

                        }

                    }

                }

            }

        }

        return ids;

    }

    /*

     * If the specified ObjectFormatIdentifier is a resrouce map namespace.

     */

    public static boolean isResourceMap(ObjectFormatIdentifier formatId) {

        boolean isResourceMap = false;

        if(formatId != null && resourceMapNamespaces != null) {

            for(String namespace : resourceMapNamespaces) {

                if(namespace != null && formatId.getValue() != null && !formatId.getValue().trim().equals("") && formatId.getValue().equals(namespace)) {

                    isResourceMap = true;

                    break;

                }

            }

        }

        return isResourceMap;

    }

    /*

     * Generate index for the id.

     */

    private void generateIndex(String id) throws Exception {

        if(id != null)  {

                SystemMetadata sysmeta = getSystemMetadata(id);

                //only update none-archived id.

                if(sysmeta != null && !sysmeta.getArchived() && sysmeta.getObsoletedBy() == null) {

                        InputStream data = getDataObject(id);

                        Identifier obsolete = sysmeta.getObsoletes();

                        List<String> obsoleteChain = null;

                        if(obsolete != null) {

                            obsoleteChain = getObsoletes(id);

                        } 

                        solrIndex.update(id, obsoleteChain, sysmeta, data);

                } else {

                    throw new Exception("IndexGenerator.generate - there is no found SystemMetadata associated with the id "+id);

                }

        }

    }

    /*

     * Remove the solr index for the list of ids

     */

    private void removeIndex(List<String> ids) throws ServiceFailure, XPathExpressionException, NotImplemented, NotFound, UnsupportedType, IOException, SolrServerException, SAXException, ParserConfigurationException {

        if(ids!= null) {

            for(String id :ids) {

                removeIndex(id);

            }

        }

    }

    /*

     * Remove the index for the id

     */

    private void removeIndex(String id) throws ServiceFailure, XPathExpressionException, NotImplemented, NotFound, UnsupportedType, IOException, SolrServerException, SAXException, ParserConfigurationException  {

        if(id != null) {

            solrIndex.remove(id);

        }

    }

    /*

     * Initialize the system metadata map

     */

    private void initSystemMetadataMap() throws FileNotFoundException, ServiceFailure{

        int times = 0;

        if(systemMetadataMap == null) {

            systemMetadataMap = DistributedMapsFactory.getSystemMetadataMap();

            /*while(true) {

                try {

                    systemMetadataMap = DistributedMapsFactory.getSystemMetadataMap();

                    break;

                } catch (FileNotFoundException e) {

                    throw e;

                } catch (ServiceFailure e) {

                    if(times <= maxAttempts) {

                        log.warn("IndexGenerator.initSystemMetadataMap - the hazelcast service is not ready : "

                                         +e.getMessage()+"\nWe will try to access it "+waitingTime/1000+" seconds later ");

                        try {

                            Thread.sleep(waitingTime);

                        } catch (Exception ee) {

                            log.warn("IndexGenerator.initSystemMetadataMap - the thread can't sleep for "+waitingTime/1000+" seconds to wait the hazelcast service");

                        }

                    } else {

                        throw new ServiceFailure("0000", "IndexGenerator.initSystemMetadataMap - the hazelcast service is not ready even though Metacat-index wailted for "+maxAttempts*waitingTime/1000+" seconds. We can't get the system metadata from it and the building index can't happen this time");

                    }

                }

                times++;

            }*/

        }

    }

    /*

     * We should call this method after calling initSystemMetadataMap since this method doesn't have the mechanism to wait the readiness of the hazelcast service

     */

    private void initObjectPathMap() throws FileNotFoundException, ServiceFailure {

        if(objectPathMap == null) {

            objectPathMap = DistributedMapsFactory.getObjectPathMap();

        }

    }

    /**

     * Get an InputStream as the data object for the specific pid.

     * @param pid

     * @return

     * @throws FileNotFoundException

     */

    private InputStream getDataObject(String pid) throws FileNotFoundException {

        Identifier identifier = new Identifier();

        identifier.setValue(pid);

        String objectPath = objectPathMap.get(identifier);

        InputStream data = null;

        data = new FileInputStream(objectPath);

        return data;

    }

    /**

     * Get the SystemMetadata for the specified id from the distributed Map.

     * The null maybe is returned if there is no system metadata found.

     * @param id  the specified id.

     * @return the SystemMetadata associated with the id.

     */

    private SystemMetadata getSystemMetadata(String id) {

        SystemMetadata metadata = null;

        if(systemMetadataMap != null && id != null) {

            Identifier identifier = new Identifier();

            identifier.setValue(id);

            metadata = systemMetadataMap.get(identifier);

        }

        return metadata;

    }

    /**

     * Get the obsoletes chain of the specified id. The returned list doesn't include

     * the specified id itself. The newer version has the lower index number in the list.

     * Empty list will be returned if there is no document to be obsoleted by this id.

     * @param id

     * @return

     */

    private List<String> getObsoletes(String id) {

        List<String> obsoletes = new ArrayList<String>();

        while (id != null) {

            SystemMetadata metadata = getSystemMetadata(id);

            id = null;//set it to be null in order to stop the while loop if the id can't be assinged to a new value in the following code.

            if(metadata != null) {

                Identifier identifier = metadata.getObsoletes();

                if(identifier != null && identifier.getValue() != null && !identifier.getValue().trim().equals("")) {

                    obsoletes.add(identifier.getValue());

                    id = identifier.getValue();

                } 

            } 

        }

        return obsoletes;

    }

    /**

     * Overwrite and do nothing

     */

    public boolean cancel() {

        return true;

    }

}