Metacat

/**

 *  Copyright: 2013 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *

 * 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.ByteArrayInputStream;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.net.MalformedURLException;

import java.util.ArrayList;

import java.util.Calendar;

import java.util.Collection;

import java.util.Date;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Set;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

import org.apache.commons.codec.EncoderException;

import org.apache.commons.collections.CollectionUtils;

import org.apache.commons.io.output.ByteArrayOutputStream;

import org.apache.commons.lang.StringUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

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

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

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

import org.apache.solr.client.solrj.response.QueryResponse;

import org.apache.solr.client.solrj.response.UpdateResponse;

import org.apache.solr.common.SolrDocument;

import org.apache.solr.common.SolrDocumentList;

import org.apache.solr.common.SolrInputDocument;

import org.apache.solr.schema.IndexSchema;

import org.dataone.cn.indexer.XMLNamespaceConfig;

import org.dataone.cn.indexer.convert.SolrDateConverter;

import org.dataone.cn.indexer.parser.BaseXPathDocumentSubprocessor;

import org.dataone.cn.indexer.parser.IDocumentDeleteSubprocessor;

import org.dataone.cn.indexer.parser.IDocumentSubprocessor;

import org.dataone.cn.indexer.parser.SolrField;

import org.dataone.cn.indexer.solrhttp.SolrDoc;

import org.dataone.cn.indexer.solrhttp.SolrElementField;

import org.dataone.exceptions.MarshallingException;

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.v2.SystemMetadata;

import org.dataone.service.util.DateTimeMarshaller;

import org.dataone.service.util.TypeMarshaller;

import org.dspace.foresite.OREParserException;

import org.w3c.dom.Document;

import org.xml.sax.SAXException;

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

import edu.ucsb.nceas.metacat.common.query.SolrQueryServiceController;

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

import edu.ucsb.nceas.metacat.index.resourcemap.ResourceMapSubprocessor;

/**

 * A class does insert, update and remove indexes to a SOLR server

 * @author tao

 *

 */

public class SolrIndex {

    public static final String ID = "id";

    private static final String IDQUERY = ID+":*";

    private List<IDocumentSubprocessor> subprocessors = null;

    private List<IDocumentDeleteSubprocessor> deleteSubprocessors = null;

    private SolrServer solrServer = null;

    private XMLNamespaceConfig xmlNamespaceConfig = null;

    private List<SolrField> sysmetaSolrFields = null;

    private static DocumentBuilderFactory documentBuilderFactory = null;

    private static DocumentBuilder builder = null;

    private static XPathFactory xpathFactory = null;

    private static XPath xpath = null;

    Log log = LogFactory.getLog(SolrIndex.class);

    static {

        documentBuilderFactory = DocumentBuilderFactory.newInstance();

        documentBuilderFactory.setNamespaceAware(true);

        try {

            builder = documentBuilderFactory.newDocumentBuilder();

        } catch (ParserConfigurationException e) {

            e.printStackTrace();

        }

        xpathFactory = XPathFactory.newInstance();

        xpath = xpathFactory.newXPath();

    }

    /**

     * Constructor

     * @throws SAXException 

     * @throws IOException 

     */

    public SolrIndex(XMLNamespaceConfig xmlNamespaceConfig, List<SolrField> sysmetaSolrFields)

                    throws XPathExpressionException, ParserConfigurationException, IOException, SAXException {

         this.xmlNamespaceConfig = xmlNamespaceConfig;

         this.sysmetaSolrFields = sysmetaSolrFields;

         init();

    }

    private void init() throws ParserConfigurationException, XPathExpressionException {

        xpath.setNamespaceContext(xmlNamespaceConfig);

        initExpressions();

    }

    private void initExpressions() throws XPathExpressionException {

        for (SolrField field : sysmetaSolrFields) {

            field.initExpression(xpath);

        }

    }

    /**

     * Get the list of the Subprocessors in this index.

     * @return the list of the Subprocessors.

     */

    public List<IDocumentSubprocessor> getSubprocessors() {

        return subprocessors;

    }

    /**

     * Set the list of Subprocessors.

     * @param subprocessorList  the list will be set.

     */

    public void setSubprocessors(List<IDocumentSubprocessor> subprocessorList) {

        for (IDocumentSubprocessor subprocessor : subprocessorList) {

        	if (subprocessor instanceof BaseXPathDocumentSubprocessor) {

        		((BaseXPathDocumentSubprocessor)subprocessor).initExpression(xpath);

        	}

        }

        this.subprocessors = subprocessorList;

    }

    public List<IDocumentDeleteSubprocessor> getDeleteSubprocessors() {

		return deleteSubprocessors;

	}

	public void setDeleteSubprocessors(

			List<IDocumentDeleteSubprocessor> deleteSubprocessors) {

		this.deleteSubprocessors = deleteSubprocessors;

	}

	/**

     * Generate the index for the given information

     * @param id

     * @param systemMetadata

     * @param dataStream

     * @return

     * @throws IOException

     * @throws SAXException

     * @throws ParserConfigurationException

     * @throws XPathExpressionException

     * @throws MarshallingException 

     * @throws SolrServerException 

     * @throws EncoderException

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws NotImplemented 

     */

    private Map<String, SolrDoc> process(String id, SystemMetadata systemMetadata, String objectPath)

                    throws IOException, SAXException, ParserConfigurationException,

                    XPathExpressionException, MarshallingException, EncoderException, SolrServerException, NotImplemented, NotFound, UnsupportedType{

        // Load the System Metadata document

        ByteArrayOutputStream systemMetadataOutputStream = new ByteArrayOutputStream();

        TypeMarshaller.marshalTypeToOutputStream(systemMetadata, systemMetadataOutputStream);

        ByteArrayInputStream systemMetadataStream = new ByteArrayInputStream(systemMetadataOutputStream.toByteArray());

        Document sysMetaDoc = generateXmlDocument(systemMetadataStream);

        if (sysMetaDoc == null) {

            log.error("Could not load System metadata for ID: " + id);

            return null;

        }

        // Extract the field values from the System Metadata

        List<SolrElementField> sysSolrFields = processSysmetaFields(sysMetaDoc, id);

        SolrDoc indexDocument = new SolrDoc(sysSolrFields);

        Map<String, SolrDoc> docs = new HashMap<String, SolrDoc>();

        docs.put(id, indexDocument);

        // get the format id for this object

        String formatId = indexDocument.getFirstFieldValue(SolrElementField.FIELD_OBJECTFORMAT);

        // Determine if subprocessors are available for this ID

        if (subprocessors != null) {

	        // for each subprocessor loaded from the spring config

	        for (IDocumentSubprocessor subprocessor : subprocessors) {

	            // Does this subprocessor apply?

	            if (subprocessor.canProcess(formatId)) {

	                // if so, then extract the additional information from the

	                // document.

	                try {

	                    // docObject = the resource map document or science

	                    // metadata document.

	                    // note that resource map processing touches all objects

	                    // referenced by the resource map.

	                	FileInputStream dataStream = new FileInputStream(objectPath);

	                    if (!dataStream.getFD().valid()) {

	                    	log.error("Could not load OBJECT file for ID,Path=" + id + ", "

                                    + objectPath);

	                        //throw new Exception("Could not load OBJECT for ID " + id );

	                    } else {

	                        docs = subprocessor.processDocument(id, docs, dataStream);

	                    }

	                } catch (Exception e) {

	                    e.printStackTrace();

	                    log.error(e.getMessage(), e);

	                    throw new SolrServerException(e.getMessage());

	                }

	            }

	        }

       }

       // TODO: in the XPathDocumentParser class in d1_cn_index_process module,

       // merge is only for resource map. We need more work here.

       for (SolrDoc mergeDoc : docs.values()) {

           if (!mergeDoc.isMerged()) {

                 mergeWithIndexedDocument(mergeDoc);

           }

       }

       //SolrElementAdd addCommand = getAddCommand(new ArrayList<SolrDoc>(docs.values()));

       return docs;

    }

    /**

     * Merge updates with existing solr documents

     * 

     * This method appears to re-set the data package field data into the

     * document about to be updated in the solr index. Since packaging

     * information is derived from the package document (resource map), this

     * information is not present when processing a document contained in a data

     * package. This method replaces those values from the existing solr index

     * record for the document being processed. -- sroseboo, 1-18-12

     * 

     * @param indexDocument

     * @return

     * @throws IOException

     * @throws EncoderException

     * @throws XPathExpressionException

     * @throws SAXException 

     * @throws ParserConfigurationException 

     * @throws SolrServerException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws NotImplemented 

     */

    // TODO:combine merge function with resourcemap merge function

    private SolrDoc mergeWithIndexedDocument(SolrDoc indexDocument) throws IOException,

            EncoderException, XPathExpressionException, SolrServerException, ParserConfigurationException, SAXException, NotImplemented, NotFound, UnsupportedType {

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

        ids.add(indexDocument.getIdentifier());

        List<SolrDoc> indexedDocuments = ResourceMapSubprocessor.getSolrDocs(ids);

        SolrDoc indexedDocument = indexedDocuments == null || indexedDocuments.size() <= 0 ? null

                : indexedDocuments.get(0);

        IndexSchema indexSchema = SolrQueryServiceController.getInstance().getSchema();

        if (indexedDocument == null || indexedDocument.getFieldList().size() <= 0) {

            return indexDocument;

        } else {

            for (SolrElementField field : indexedDocument.getFieldList()) {

                if ((field.getName().equals(SolrElementField.FIELD_ISDOCUMENTEDBY)

                        || field.getName().equals(SolrElementField.FIELD_DOCUMENTS) || field

                        .getName().equals(SolrElementField.FIELD_RESOURCEMAP))

                        && !indexDocument.hasFieldWithValue(field.getName(), field.getValue())) {

                    indexDocument.addField(field);

                } else if (!indexSchema.isCopyFieldTarget(indexSchema.getField(field.getName())) && !indexDocument.hasField(field.getName())) {

                    indexDocument.addField(field);

                }

            }

            indexDocument.setMerged(true);

            return indexDocument;

        }

    }

    /*

     * Generate a Document from the InputStream

     */

    private Document generateXmlDocument(InputStream smdStream) throws SAXException {

        Document doc = null;

        try {

            doc = builder.parse(smdStream);

        } catch (IOException e) {

            log.error(e.getMessage(), e);

        }

        return doc;

    }

    /*

     * Index the fields of the system metadata

     */

    private List<SolrElementField> processSysmetaFields(Document doc, String identifier) {

        List<SolrElementField> fieldList = new ArrayList<SolrElementField>();

        // solrFields is the list of fields defined in the application context

        for (SolrField field : sysmetaSolrFields) {

            try {

                // the field.getFields method can return a single value or

                // multiple values for multi-valued fields

                // or can return multiple SOLR document fields.

                fieldList.addAll(field.getFields(doc, identifier));

            } catch (Exception e) {

                e.printStackTrace();

            }

        }

        return fieldList;

    }

    /**

     * Check the parameters of the insert or update methods.

     * @param pid

     * @param systemMetadata

     * @param data

     * @throws SolrServerException

     */

    private void checkParams(Identifier pid, SystemMetadata systemMetadata, String objectPath) throws SolrServerException {

        if(pid == null || pid.getValue() == null || pid.getValue().trim().equals("")) {

            throw new SolrServerException("The identifier of the indexed document should not be null or blank.");

        }

        if(systemMetadata == null) {

            throw new SolrServerException("The system metadata of the indexed document "+pid.getValue()+ " should not be null.");

        }

        if(objectPath == null) {

            throw new SolrServerException("The indexed document itself for pid "+pid.getValue()+" should not be null.");

        }

    }

    /**

     * Insert the indexes for a document.

     * @param pid  the id of this document

     * @param systemMetadata  the system metadata associated with the data object

     * @param data  the path to the object file itself

     * @throws SolrServerException 

     * @throws MarshallingException 

     * @throws EncoderException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws NotImplemented 

     */

    private synchronized void insert(Identifier pid, SystemMetadata systemMetadata, String objectPath) 

                    throws IOException, SAXException, ParserConfigurationException,

                    XPathExpressionException, SolrServerException, MarshallingException, EncoderException, NotImplemented, NotFound, UnsupportedType {

        checkParams(pid, systemMetadata, objectPath);

        Map<String, SolrDoc> docs = process(pid.getValue(), systemMetadata, objectPath);

        //transform the Map to the SolrInputDocument which can be used by the solr server

        if(docs != null) {

            Set<String> ids = docs.keySet();

            for(String id : ids) {

                if(id != null) {

                    SolrDoc doc = docs.get(id);

                    insertToIndex(doc);

                }

            }

        }

    }

    /**

     * Adds the given fields to the solr index for the given pid, preserving the index values

     * that previously existed

     * @param pid

     * @param fields

     */

    public void insertFields(Identifier pid, Map<String, List<Object>> fields) {

    	try {

			// copy the original values already indexed for this document	

	    	SolrQuery query = new SolrQuery("id:\"" + pid.getValue() + "\"");

	    	QueryResponse res = solrServer.query(query);

	    	SolrDoc doc = new SolrDoc();

	    	// include existing values if they exist

	        IndexSchema indexSchema = SolrQueryServiceController.getInstance().getSchema();

	        if (res.getResults().size() > 0) {

		        SolrDocument orig = res.getResults().get(0);

		    	for (String fieldName: orig.getFieldNames()) {

		        	//  don't transfer the copyTo fields, otherwise there are errors

		        	if (indexSchema.isCopyFieldTarget(indexSchema.getField(fieldName))) {

		        		continue;

		        	}

		        	for (Object value: orig.getFieldValues(fieldName)) {

		        		String stringValue = value.toString();

		        		// special handling for dates in ISO 8601

		        		if (value instanceof Date) {

		        			stringValue = DateTimeMarshaller.serializeDateToUTC((Date)value);

		        			SolrDateConverter converter = new SolrDateConverter();

		        			stringValue = converter.convert(stringValue);

		        		}

						SolrElementField field = new SolrElementField(fieldName, stringValue);

						log.debug("Adding field: " + fieldName);

						doc.addField(field);

		        	}

		        }

	        }

	        // add the additional fields we are trying to include in the index

	        for (String fieldName: fields.keySet()) {

	    		List<Object> values = fields.get(fieldName);

	    		for (Object value: values) {

	    			if (!doc.hasFieldWithValue(fieldName, value.toString())) {

	    				if (indexSchema.getField(fieldName).multiValued()) {

	    					doc.addField(new SolrElementField(fieldName, value.toString()));

	    				} else {

	    	    	    	doc.updateOrAddField(fieldName, value.toString());

	    				}

	    			}

	    		}

	    	}

	        // make sure there is an id in the solrdoc so it is added to the index

	        if (!doc.hasField(ID)) {

	        	doc.updateOrAddField(ID, pid.getValue());

	        }

	        // insert the whole thing

	        insertToIndex(doc);

    	} catch (Exception e) {

    		String error = "SolrIndex.insetFields - could not update the solr index: " + e.getMessage();

            writeEventLog(null, pid, error);

            log.error(error, e);

    	}

    }

    /*

     * Insert a SolrDoc to the solr server.

     */

    private synchronized void insertToIndex(SolrDoc doc) throws SolrServerException, IOException {

        if(doc != null ) {

            SolrInputDocument solrDoc = new SolrInputDocument();

            List<SolrElementField> list = doc.getFieldList();

            if(list != null) {

                //solrDoc.addField(METACATPIDFIELD, pid);

                Iterator<SolrElementField> iterator = list.iterator();

                while (iterator.hasNext()) {

                    SolrElementField field = iterator.next();

                    if(field != null) {

                        String value = field.getValue();

                        String name = field.getName();

                        //System.out.println("add name/value pair - "+name+"/"+value);

                        solrDoc.addField(name, value);

                    }

                }

            }

            if(!solrDoc.isEmpty()) {

                /*IndexEvent event = new IndexEvent();

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

                Identifier pid = new Identifier();

                pid.setValue(doc.getIdentifier());

                event.setIdentifier(pid);*/

                try {

                    UpdateResponse response = solrServer.add(solrDoc);

                    solrServer.commit();

                    /*event.setType(IndexEvent.SUCCESSINSERT);

                    event.setDescription("Successfully insert the solr index for the id "+pid.getValue());

                    try {

                        EventlogFactory.createIndexEventLog().write(event);

                    } catch (Exception e) {

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

                    }*/

                } catch (SolrServerException e) {

                    /*event.setAction(Event.CREATE);

                    event.setDescription("Failed to insert the solr index for the id "+pid.getValue()+" since "+e.getMessage());

                    try {

                        EventlogFactory.createIndexEventLog().write(event);

                    } catch (Exception ee) {

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

                    }*/

                    throw e;

                } catch (IOException e) {

                    /*event.setAction(Event.CREATE);

                    event.setDescription("Failed to insert the solr index for the id "+pid.getValue()+" since "+e.getMessage());

                    try {

                        EventlogFactory.createIndexEventLog().write(event);

                    } catch (Exception ee) {

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

                    }*/

                    throw e;

                }

                //System.out.println("=================the response is:\n"+response.toString());

            }

        }

    }

    /**

     * Update the solr index. This method handles the three scenarios:

     * 1. Remove an existing doc - if the the system metadata shows the value of the archive is true,

     *    remove the index for the previous version(s) and generate new index for the doc.

     * 2. Add a new doc - if the system metadata shows the value of the archive is false, generate the

     *    index for the doc.

     */

    public void update(Identifier pid, SystemMetadata systemMetadata) {

        if(systemMetadata==null || pid==null) {

            log.error("SolrIndex.update - the systemMetadata or pid is null. So nothing will be indexed.");

            return;

        }

        String objectPath = null;

        try {

            if (systemMetadata.getArchived() == null || !systemMetadata.getArchived()) {

                objectPath = DistributedMapsFactory.getObjectPathMap().get(pid);

            }

            update(pid, systemMetadata, objectPath);

            EventlogFactory.createIndexEventLog().remove(pid);

        } catch (Exception e) {

            String error = "SolrIndex.update - could not update the solr index since " + e.getMessage();

            writeEventLog(systemMetadata, pid, error);

            log.error(error, e);

        }

    }

    /**

     * Update the solr index. This method handles the three scenarios:

     * 1. Remove an existing doc - if the the system metadata shows the value of the archive is true,

     *    remove the index for the previous version(s) and generate new index for the doc.

     * 2. Add a new doc - if the system metadata shows the value of the archive is false, generate the

     *    index for the doc.

     * @param pid

     * @param systemMetadata

     * @param data

     * @throws SolrServerException

     * @throws ServiceFailure

     * @throws XPathExpressionException

     * @throws NotImplemented

     * @throws NotFound

     * @throws UnsupportedType

     * @throws IOException

     * @throws SAXException

     * @throws ParserConfigurationException

     * @throws OREParserException

     * @throws MarshallingException

     * @throws EncoderException

     */

    void update(Identifier pid, SystemMetadata systemMetadata, String objectPath) throws Exception {

        //checkParams(pid, systemMetadata, objectPath);

        if(systemMetadata==null || pid==null) {

            log.error("SolrIndex.update - the systemMetadata or pid is null. So nothing will be indexed.");

            return;

        }

        boolean isArchive = systemMetadata.getArchived() != null && systemMetadata.getArchived();

        if(isArchive ) {

            //delete the index for the archived objects

            remove(pid.getValue(), systemMetadata);

            log.info("SolrIndex.update============================= archive the idex for the identifier "+pid);

        } else {

            //generate index for either add or update.

            insert(pid, systemMetadata, objectPath);

            log.info("SolrIndex.update============================= insert index for the identifier "+pid);

        }

    }

    /*

     * Is the pid a resource map

     */

    private boolean isDataPackage(String pid, SystemMetadata sysmeta) throws FileNotFoundException, ServiceFailure {

        boolean isDataPackage = false;

        //SystemMetadata sysmeta = DistributedMapsFactory.getSystemMetadata(pid);

        if(sysmeta != null) {

            isDataPackage = IndexGeneratorTimerTask.isResourceMap(sysmeta.getFormatId());

        }

        return isDataPackage;

    }

    private boolean isPartOfDataPackage(String pid) throws XPathExpressionException, NotImplemented, NotFound, UnsupportedType, SolrServerException, IOException, ParserConfigurationException, SAXException {

        SolrDoc dataPackageIndexDoc = ResourceMapSubprocessor.getSolrDoc(pid);

        if (dataPackageIndexDoc != null) {

            String resourceMapId = dataPackageIndexDoc

                    .getFirstFieldValue(SolrElementField.FIELD_RESOURCEMAP);

            return StringUtils.isNotEmpty(resourceMapId);

        } else {

            return false;

        }

    }

    /**

     * Remove the indexed associated with specified pid.

     * @param pid  the pid which the indexes are associated with

     * @throws IOException

     * @throws SolrServerException

     * @throws ParserConfigurationException 

     * @throws SAXException 

     * @throws UnsupportedType 

     * @throws NotFound 

     * @throws NotImplemented 

     * @throws XPathExpressionException 

     * @throws ServiceFailure 

     * @throws OREParserException 

     */

    private void remove(String pid, SystemMetadata sysmeta) throws Exception {

        if (isDataPackage(pid, sysmeta)) {

            removeDataPackage(pid);

        } else if (isPartOfDataPackage(pid)) {

            removeFromDataPackage(pid);

        } else {

            removeFromIndex(pid);

        }

    }

    /*

     * Remove the resource map from the solr index. It doesn't only remove the index for itself and also

     * remove the relationship for the related metadata and data objects.

     */

    private void removeDataPackage(String pid) throws Exception {

        removeFromIndex(pid);

        List<SolrDoc> docsToUpdate = getUpdatedSolrDocsByRemovingResourceMap(pid);

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

            //SolrElementAdd addCommand = new SolrElementAdd(docsToUpdate);

            //httpService.sendUpdate(solrIndexUri, addCommand);

            for(SolrDoc doc : docsToUpdate) {

                removeFromIndex(doc.getIdentifier());

                insertToIndex(doc);

            }

        }

    }

    /*

     * Get the list of the solr doc which need to be updated because the removal of the resource map

     */

    private List<SolrDoc> getUpdatedSolrDocsByRemovingResourceMap(String resourceMapId)

            throws UnsupportedType, NotFound, SolrServerException, ParserConfigurationException, SAXException, MalformedURLException, IOException, XPathExpressionException {

        List<SolrDoc> updatedSolrDocs = null;

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

            /*List<SolrDoc> docsContainResourceMap = httpService.getDocumentsByResourceMap(

                    solrQueryUri, resourceMapId);*/

            List<SolrDoc> docsContainResourceMap = ResourceMapSubprocessor.getDocumentsByResourceMap(resourceMapId);

            updatedSolrDocs = removeResourceMapRelationship(docsContainResourceMap,

                    resourceMapId);

        }

        return updatedSolrDocs;

    }

    /*

     * Get the list of the solr doc which need to be updated because the removal of the resource map

     */

    private List<SolrDoc> removeResourceMapRelationship(List<SolrDoc> docsContainResourceMap,

            String resourceMapId) throws XPathExpressionException, IOException {

        List<SolrDoc> totalUpdatedSolrDocs = new ArrayList<SolrDoc>();

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

            for (SolrDoc doc : docsContainResourceMap) {

                List<SolrDoc> updatedSolrDocs = new ArrayList<SolrDoc>();

                List<String> resourceMapIdStrs = doc

                        .getAllFieldValues(SolrElementField.FIELD_RESOURCEMAP);

                List<String> dataIdStrs = doc

                        .getAllFieldValues(SolrElementField.FIELD_DOCUMENTS);

                List<String> metadataIdStrs = doc

                        .getAllFieldValues(SolrElementField.FIELD_ISDOCUMENTEDBY);

                if ((dataIdStrs == null || dataIdStrs.isEmpty())

                        && (metadataIdStrs == null || metadataIdStrs.isEmpty())) {

                    // only has resourceMap field, doesn't have either documentBy or documents fields.

                    // so we only remove the resource map field.

                    doc.removeFieldsWithValue(SolrElementField.FIELD_RESOURCEMAP, resourceMapId);

                    updatedSolrDocs.add(doc);

                } else if ((dataIdStrs != null && !dataIdStrs.isEmpty())

                        && (metadataIdStrs == null || metadataIdStrs.isEmpty())) {

                    //The solr doc is for a metadata object since the solr doc documents data files

                    updatedSolrDocs = removeAggregatedItems(resourceMapId, doc, resourceMapIdStrs,

                            dataIdStrs, SolrElementField.FIELD_DOCUMENTS);

                } else if ((dataIdStrs == null || dataIdStrs.isEmpty())

                        && (metadataIdStrs != null && !metadataIdStrs.isEmpty())) {

                    //The solr doc is for a data object since it documentedBy elements.

                    updatedSolrDocs = removeAggregatedItems(resourceMapId, doc, resourceMapIdStrs,

                            metadataIdStrs, SolrElementField.FIELD_ISDOCUMENTEDBY);

                } else if ((dataIdStrs != null && !dataIdStrs.isEmpty())

                        && (metadataIdStrs != null && !metadataIdStrs.isEmpty())){

                    // both metadata and data for one object

                    List<SolrDoc> solrDocsRemovedDocuments = removeAggregatedItems(resourceMapId, doc, resourceMapIdStrs,

                            dataIdStrs, SolrElementField.FIELD_DOCUMENTS);

                    List<SolrDoc> solrDocsRemovedDocumentBy = removeAggregatedItems(resourceMapId, doc, resourceMapIdStrs,

                            metadataIdStrs, SolrElementField.FIELD_ISDOCUMENTEDBY);

                    updatedSolrDocs = mergeUpdatedSolrDocs(solrDocsRemovedDocumentBy, solrDocsRemovedDocuments);

                }

                //move them to the final result

                if(updatedSolrDocs != null) {

                    for(SolrDoc updatedDoc: updatedSolrDocs) {

                        totalUpdatedSolrDocs.add(updatedDoc);

                    }

                }

            }

        }

        return totalUpdatedSolrDocs;

    }

    /*

     * Process the list of ids of the documentBy/documents in a slor doc.

     */

    private List<SolrDoc> removeAggregatedItems(String targetResourceMapId, SolrDoc doc,

            List<String> resourceMapIdsInDoc, List<String> aggregatedItemsInDoc, String fieldNameRemoved) {

        List<SolrDoc> updatedSolrDocs = new ArrayList<SolrDoc>();

        if (doc != null && resourceMapIdsInDoc != null && aggregatedItemsInDoc != null

                && fieldNameRemoved != null) {

            if (resourceMapIdsInDoc.size() == 1) {

                //only has one resource map. remove the resource map. also remove the documentBy

                doc.removeFieldsWithValue(SolrElementField.FIELD_RESOURCEMAP, targetResourceMapId);

                doc.removeAllFields(fieldNameRemoved);

                updatedSolrDocs.add(doc);

            } else if (resourceMapIdsInDoc.size() > 1) {

                //we have multiple resource maps. We should match them.                     

                Map<String, String> ids = matchResourceMapsAndItems(doc.getIdentifier(),

                        targetResourceMapId, resourceMapIdsInDoc, aggregatedItemsInDoc, fieldNameRemoved);

                if (ids != null) {

                    for (String id : ids.keySet()) {

                        doc.removeFieldsWithValue(fieldNameRemoved, id);

                    }

                }

                doc.removeFieldsWithValue(SolrElementField.FIELD_RESOURCEMAP,

                        targetResourceMapId);

                updatedSolrDocs.add(doc);

                /*if (aggregatedItemsInDoc.size() > 1) {

                } else {

                    //multiple resource map aggregate same metadata and data. Just remove the resource map

                    doc.removeFieldsWithValue(SolrElementField.FIELD_RESOURCEMAP,

                            targetResourceMapId);

                    updatedSolrDocs.add(doc);

                }*/

            }

        }

        return updatedSolrDocs;

    }

    /*

     * Return a map of mapping aggregation id map the target resourceMapId.

     * This will look the aggregation information in another side - If the targetId

     * is a metadata object, we will look the data objects which it describes; If 

     * the targetId is a data object, we will look the metadata object which documents it.

     */

    private Map<String, String> matchResourceMapsAndItems(String targetId,

            String targetResourceMapId, List<String> originalResourceMaps, List<String> aggregatedItems, String fieldName) {

        Map<String, String> map = new HashMap<String, String>();

        if (targetId != null && targetResourceMapId != null && aggregatedItems != null

                && fieldName != null) {

            String newFieldName = null;

            if (fieldName.equals(SolrElementField.FIELD_ISDOCUMENTEDBY)) {

                newFieldName = SolrElementField.FIELD_DOCUMENTS;

            } else if (fieldName.equals(SolrElementField.FIELD_DOCUMENTS)) {

                newFieldName = SolrElementField.FIELD_ISDOCUMENTEDBY;

            }

            if (newFieldName != null) {

                for (String item : aggregatedItems) {

                    SolrDoc doc = null;

                    try {

                        doc = getDocumentById(item);

                        List<String> fieldValues = doc.getAllFieldValues(newFieldName);

                        List<String> resourceMapIds = doc

                                .getAllFieldValues(SolrElementField.FIELD_RESOURCEMAP);

                        if ((fieldValues != null && fieldValues.contains(targetId))

                                && (resourceMapIds != null && resourceMapIds

                                        .contains(targetResourceMapId))) {

                            //okay, we found the target aggregation item id and the resource map id

                            //in this solr doc. However, we need check if another resource map with different

                            //id but specify the same relationship. If we have the id(s), we should not

                            // remove the documents( or documentBy) element since we need to preserve the 

                            // relationship for the remain resource map. 

                            boolean hasDuplicateIds = false;

                            if(originalResourceMaps != null) {

                               for(String id :resourceMapIds) {

                                    if (originalResourceMaps.contains(id) && !id.equals(targetResourceMapId)) {

                                        hasDuplicateIds = true;

                                        break;

                                    }

                                }

                            }

                            if(!hasDuplicateIds) {

                                map.put(item, targetResourceMapId);

                            }

                        }

                    } catch (Exception e) {

                        log.warn("SolrIndex.matchResourceMapsAndItems - can't get the solrdoc for the id "

                                + item + " since " + e.getMessage());

                    }

                }

            }

        }

        return map;

    }

    /*

     * Get the solr index doc from the index server for the given id.

     */

    private SolrDoc getDocumentById(String id) throws NotImplemented, NotFound, UnsupportedType, 

                SolrServerException, ParserConfigurationException, SAXException, XPathExpressionException, IOException {

        SolrDoc doc = ResourceMapSubprocessor.getSolrDoc(id);

        return doc;

    }

    /*

     * Merge two list of updated solr docs. removedDocumentBy has the correct information about documentBy element.

     * removedDocuments has the correct information about the documents element.

     * So we go through the two list and found the two docs having the same identifier.

     * Get the list of the documents value from the one in the removedDoucments (1). 

     * Remove all values of documents from the one in the removedDocumentBy. 

     * Then copy the list of documents value from (1) to to the one in the removedDocumentBy.

     */

    private List<SolrDoc> mergeUpdatedSolrDocs(List<SolrDoc>removedDocumentBy, List<SolrDoc>removedDocuments) {

        List<SolrDoc> mergedDocuments = new ArrayList<SolrDoc>();

        if(removedDocumentBy == null || removedDocumentBy.isEmpty()) {

            mergedDocuments = removedDocuments;

        } else if (removedDocuments == null || removedDocuments.isEmpty()) {

            mergedDocuments = removedDocumentBy;

        } else {

            int sizeOfDocBy = removedDocumentBy.size();

            int sizeOfDocs = removedDocuments.size();

            for(int i=sizeOfDocBy-1; i>= 0; i--) {

                SolrDoc docInRemovedDocBy = removedDocumentBy.get(i);

                for(int j= sizeOfDocs-1; j>=0; j--) {

                    SolrDoc docInRemovedDocs = removedDocuments.get(j);

                    if(docInRemovedDocBy.getIdentifier().equals(docInRemovedDocs.getIdentifier())) {

                        //find the same doc in both list. let's merge them.

                        //first get all the documents element from the docWithDocs(it has the correct information about the documents element)

                        List<String> idsInDocuments = docInRemovedDocs.getAllFieldValues(SolrElementField.FIELD_DOCUMENTS);

                        docInRemovedDocBy.removeAllFields(SolrElementField.FIELD_DOCUMENTS);//clear out any documents element in docInRemovedDocBy

                        //add the Documents element from the docInRemovedDocs if it has any.

                        // The docInRemovedDocs has the correct information about the documentBy. Now it copied the correct information of the documents element.

                        // So docInRemovedDocs has both correct information about the documentBy and documents elements.

                        if(idsInDocuments != null) {

                            for(String id : idsInDocuments) {

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

                                    docInRemovedDocBy.addField(new SolrElementField(SolrElementField.FIELD_DOCUMENTS, id));