CommunicationsManager.java

Go to the documentation of this file.

/*
 * Sleuth Kit Data Model
 *
 * Copyright 2017-2020 Basis Technology Corp.
 * Contact: carrier <at> sleuthkit <dot> org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.sleuthkit.datamodel;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.sleuthkit.datamodel.Blackboard.BlackboardException;
import org.sleuthkit.datamodel.SleuthkitCase.CaseDbConnection;
import static org.sleuthkit.datamodel.SleuthkitCase.closeResultSet;
import static org.sleuthkit.datamodel.SleuthkitCase.closeStatement;

public final class CommunicationsManager {

        private static final Logger LOGGER = Logger.getLogger(CommunicationsManager.class.getName());

        private final SleuthkitCase db;

        private final Map<Account.Type, Integer> accountTypeToTypeIdMap
                        = new ConcurrentHashMap<>();
        private final Map<String, Account.Type> typeNameToAccountTypeMap
                        = new ConcurrentHashMap<>();

        // Artifact types that can represent a relationship between accounts. 
        private static final Set<Integer> RELATIONSHIP_ARTIFACT_TYPE_IDS = new HashSet<Integer>(Arrays.asList(
                        BlackboardArtifact.ARTIFACT_TYPE.TSK_MESSAGE.getTypeID(),
                        BlackboardArtifact.ARTIFACT_TYPE.TSK_EMAIL_MSG.getTypeID(),
                        BlackboardArtifact.ARTIFACT_TYPE.TSK_CONTACT.getTypeID(),
                        BlackboardArtifact.ARTIFACT_TYPE.TSK_CALLLOG.getTypeID()
        ));
        private static final String RELATIONSHIP_ARTIFACT_TYPE_IDS_CSV_STR = StringUtils.buildCSVString(RELATIONSHIP_ARTIFACT_TYPE_IDS);

        CommunicationsManager(SleuthkitCase skCase) throws TskCoreException {
                this.db = skCase;
                initAccountTypes();
        }

        private void initAccountTypes() throws TskCoreException {
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseWriteLock();
                Statement statement = null;
                ResultSet resultSet = null;

                try {
                        statement = connection.createStatement();
                        // Read the table
                        int count = readAccountTypes();
                        if (0 == count) {
                                // Table is empty, populate it with predefined types
                                for (Account.Type type : Account.Type.PREDEFINED_ACCOUNT_TYPES) {
                                        try {
                                                statement.execute("INSERT INTO account_types (type_name, display_name) VALUES ( '" + type.getTypeName() + "', '" + type.getDisplayName() + "')"); //NON-NLS
                                        } catch (SQLException ex) {
                                                resultSet = connection.executeQuery(statement, "SELECT COUNT(*) AS count FROM account_types WHERE type_name = '" + type.getTypeName() + "'"); //NON-NLS
                                                resultSet.next();
                                                if (resultSet.getLong("count") == 0) {
                                                        throw ex;
                                                }
                                                resultSet.close();
                                        }

                                        ResultSet rs2 = connection.executeQuery(statement, "SELECT account_type_id FROM account_types WHERE type_name = '" + type.getTypeName() + "'"); //NON-NLS
                                        rs2.next();
                                        int typeID = rs2.getInt("account_type_id");
                                        rs2.close();

                                        Account.Type accountType = new Account.Type(type.getTypeName(), type.getDisplayName());
                                        this.accountTypeToTypeIdMap.put(accountType, typeID);
                                        this.typeNameToAccountTypeMap.put(type.getTypeName(), accountType);
                                }
                        }
                } catch (SQLException ex) {
                        LOGGER.log(Level.SEVERE, "Failed to add row to account_types", ex);
                } finally {
                        closeResultSet(resultSet);
                        closeStatement(statement);
                        connection.close();
                        db.releaseSingleUserCaseWriteLock();
                }
        }

        private int readAccountTypes() throws TskCoreException {
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement statement = null;
                ResultSet resultSet = null;
                int count = 0;

                try {
                        statement = connection.createStatement();

                        // If the account_types table is already populated, say when opening a case,  then load it
                        resultSet = connection.executeQuery(statement, "SELECT COUNT(*) AS count FROM account_types"); //NON-NLS
                        resultSet.next();
                        if (resultSet.getLong("count") > 0) {

                                resultSet.close();
                                resultSet = connection.executeQuery(statement, "SELECT * FROM account_types");
                                while (resultSet.next()) {
                                        Account.Type accountType = new Account.Type(resultSet.getString("type_name"), resultSet.getString("display_name"));
                                        this.accountTypeToTypeIdMap.put(accountType, resultSet.getInt("account_type_id"));
                                        this.typeNameToAccountTypeMap.put(accountType.getTypeName(), accountType);
                                }
                                count = this.typeNameToAccountTypeMap.size();
                        }

                } catch (SQLException ex) {
                        throw new TskCoreException("Failed to read account_types", ex);
                } finally {
                        closeResultSet(resultSet);
                        closeStatement(statement);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }

                return count;
        }

        SleuthkitCase getSleuthkitCase() {
                return this.db;
        }

        // NOTE: Full name given for Type for doxygen linking
        public org.sleuthkit.datamodel.Account.Type addAccountType(String accountTypeName, String displayName) throws TskCoreException {
                Account.Type accountType = new Account.Type(accountTypeName, displayName);

                // check if already in map
                if (this.accountTypeToTypeIdMap.containsKey(accountType)) {
                        return accountType;
                }

                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseWriteLock();
                Statement s = null;
                ResultSet rs = null;
                try {
                        connection.beginTransaction();
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, "SELECT * FROM account_types WHERE type_name = '" + accountTypeName + "'"); //NON-NLS
                        if (!rs.next()) {
                                rs.close();

                                s.execute("INSERT INTO account_types (type_name, display_name) VALUES ( '" + accountTypeName + "', '" + displayName + "')"); //NON-NLS

                                // Read back the typeID
                                rs = connection.executeQuery(s, "SELECT * FROM account_types WHERE type_name = '" + accountTypeName + "'"); //NON-NLS
                                rs.next();

                                int typeID = rs.getInt("account_type_id");
                                accountType = new Account.Type(rs.getString("type_name"), rs.getString("display_name"));

                                this.accountTypeToTypeIdMap.put(accountType, typeID);
                                this.typeNameToAccountTypeMap.put(accountTypeName, accountType);

                                connection.commitTransaction();

                                return accountType;
                        } else {
                                int typeID = rs.getInt("account_type_id");

                                accountType = new Account.Type(rs.getString("type_name"), rs.getString("display_name"));
                                this.accountTypeToTypeIdMap.put(accountType, typeID);

                                return accountType;
                        }
                } catch (SQLException ex) {
                        connection.rollbackTransaction();
                        throw new TskCoreException("Error adding account type", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseWriteLock();
                }
        }

        // NOTE: Full name given for Type for doxygen linking
        public AccountFileInstance createAccountFileInstance(org.sleuthkit.datamodel.Account.Type accountType, String accountUniqueID, String moduleName, Content sourceFile) throws TskCoreException, InvalidAccountIDException {

                // make or get the Account (unique at the case-level)
                Account account = getOrCreateAccount(accountType, normalizeAccountID(accountType, accountUniqueID));

                /*
                 * make or get the artifact. Will not create one if it already exists
                 * for the sourceFile. Such as an email PST that has the same email
                 * address multiple times. Only one artifact is created for each email
                 * message in that PST.
                 */
                BlackboardArtifact accountArtifact = getOrCreateAccountFileInstanceArtifact(accountType, normalizeAccountID(accountType, accountUniqueID), moduleName, sourceFile);

                // The account instance map was unused so we have removed it from the database, 
                // but we expect we may need it so I am preserving this method comment and usage here.
                // add a row to Accounts to Instances mapping table
                // @@@ BC: Seems like we should only do this if we had to create the artifact. 
                // But, it will probably fail to create a new one based on unique constraints. 
                // addAccountFileInstanceMapping(account.getAccountID(), accountArtifact.getArtifactID());
                return new AccountFileInstance(accountArtifact, account);
        }

        // NOTE: Full name given for Type for doxygen linking
        public Account getAccount(org.sleuthkit.datamodel.Account.Type accountType, String accountUniqueID) throws TskCoreException, InvalidAccountIDException {
                Account account = null;
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;
                try {
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, "SELECT * FROM accounts WHERE account_type_id = " + getAccountTypeId(accountType)
                                        + " AND account_unique_identifier = '" + normalizeAccountID(accountType, accountUniqueID) + "'"); //NON-NLS

                        if (rs.next()) {
                                account = new Account(rs.getInt("account_id"), accountType,
                                                rs.getString("account_unique_identifier"));
                        }
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account type id", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }

                return account;
        }

        // NOTE: Full name given for Type for doxygen linking
        public void addRelationships(AccountFileInstance sender, List<AccountFileInstance> recipients,
                        BlackboardArtifact sourceArtifact, org.sleuthkit.datamodel.Relationship.Type relationshipType, long dateTime) throws TskCoreException, TskDataException {

                if (relationshipType.isCreatableFrom(sourceArtifact) == false) {
                        throw new TskDataException("Can not make a " + relationshipType.getDisplayName()
                                        + " relationship from a" + sourceArtifact.getDisplayName());
                }

                /*
                 * Enforce that all accounts and the relationship between them are from
                 * the same 'source'. This is required for the queries to work
                 * correctly.
                 */
                // Currently we do not save the direction of communication
                List<Long> accountIDs = new ArrayList<Long>();

                if (null != sender) {
                        accountIDs.add(sender.getAccount().getAccountID());
                        if (sender.getDataSourceObjectID() != sourceArtifact.getDataSourceObjectID()) {
                                throw new TskDataException("Sender and relationship are from different data sources :"
                                                + "Sender source ID" + sender.getDataSourceObjectID() + " != relationship source ID" + sourceArtifact.getDataSourceObjectID());
                        }
                }

                for (AccountFileInstance recipient : recipients) {
                        accountIDs.add(recipient.getAccount().getAccountID());
                        if (recipient.getDataSourceObjectID() != sourceArtifact.getDataSourceObjectID()) {
                                throw new TskDataException("Recipient and relationship are from different data sources :"
                                                + "Recipient source ID" + recipient.getDataSourceObjectID() + " != relationship source ID" + sourceArtifact.getDataSourceObjectID());
                        }
                }

                for (int i = 0; i < accountIDs.size(); i++) {
                        for (int j = i + 1; j < accountIDs.size(); j++) {
                                try {
                                        addAccountsRelationship(accountIDs.get(i), accountIDs.get(j),
                                                        sourceArtifact, relationshipType, dateTime);
                                } catch (TskCoreException ex) {
                                        // @@@ This should probably not be caught and instead we stop adding
                                        LOGGER.log(Level.WARNING, "Error adding relationship", ex); //NON-NLS
                                }
                        }
                }
        }

        private Account getOrCreateAccount(Account.Type accountType, String accountUniqueID) throws TskCoreException, InvalidAccountIDException {
                Account account = getAccount(accountType, accountUniqueID);
                if (null == account) {
                        String query = " INTO accounts (account_type_id, account_unique_identifier) "
                                        + "VALUES ( " + getAccountTypeId(accountType) + ", '"
                                        + normalizeAccountID(accountType, accountUniqueID) + "'" + ")";
                        switch (db.getDatabaseType()) {
                                case POSTGRESQL:
                                        query = "INSERT " + query + " ON CONFLICT DO NOTHING"; //NON-NLS
                                        break;
                                case SQLITE:
                                        query = "INSERT OR IGNORE " + query;
                                        break;
                                default:
                                        throw new TskCoreException("Unknown DB Type: " + db.getDatabaseType().name());
                        }

                        CaseDbConnection connection = db.getConnection();
                        db.acquireSingleUserCaseWriteLock();
                        Statement s = null;
                        ResultSet rs = null;
                        try {
                                connection.beginTransaction();
                                s = connection.createStatement();

                                s.execute(query);

                                connection.commitTransaction();
                                account = getAccount(accountType, accountUniqueID);
                        } catch (SQLException ex) {
                                connection.rollbackTransaction();
                                throw new TskCoreException("Error adding an account", ex);
                        } finally {
                                closeResultSet(rs);
                                closeStatement(s);
                                connection.close();
                                db.releaseSingleUserCaseWriteLock();
                        }
                }

                return account;
        }

        private BlackboardArtifact getOrCreateAccountFileInstanceArtifact(Account.Type accountType, String accountUniqueID, String moduleName, Content sourceFile) throws TskCoreException {
                BlackboardArtifact accountArtifact = getAccountFileInstanceArtifact(accountType, accountUniqueID, sourceFile);
                if (accountArtifact == null) {
                        accountArtifact = db.newBlackboardArtifact(BlackboardArtifact.ARTIFACT_TYPE.TSK_ACCOUNT, sourceFile.getId());
                        Collection<BlackboardAttribute> attributes = new ArrayList<>();
                        attributes.add(new BlackboardAttribute(BlackboardAttribute.ATTRIBUTE_TYPE.TSK_ACCOUNT_TYPE, moduleName, accountType.getTypeName()));
                        attributes.add(new BlackboardAttribute(BlackboardAttribute.ATTRIBUTE_TYPE.TSK_ID, moduleName, accountUniqueID));
                        accountArtifact.addAttributes(attributes);
                        try {
                                db.getBlackboard().postArtifact(accountArtifact, moduleName);
                        } catch (BlackboardException ex) {
                                LOGGER.log(Level.SEVERE, String.format("Error posting new account artifact to the blackboard (object ID = %d)", accountArtifact.getId()), ex);
                        }
                }
                return accountArtifact;
        }

        private BlackboardArtifact getAccountFileInstanceArtifact(Account.Type accountType, String accountUniqueID, Content sourceFile) throws TskCoreException {
                BlackboardArtifact accountArtifact = null;
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();
                        String queryStr = "SELECT artifacts.artifact_id AS artifact_id,"
                                        + " artifacts.obj_id AS obj_id,"
                                        + " artifacts.artifact_obj_id AS artifact_obj_id,"
                                        + " artifacts.data_source_obj_id AS data_source_obj_id,"
                                        + " artifacts.artifact_type_id AS artifact_type_id,"
                                        + " artifacts.review_status_id AS review_status_id"
                                        + " FROM blackboard_artifacts AS artifacts"
                                        + "     JOIN blackboard_attributes AS attr_account_type"
                                        + "             ON artifacts.artifact_id = attr_account_type.artifact_id"
                                        + " JOIN blackboard_attributes AS attr_account_id"
                                        + "             ON artifacts.artifact_id = attr_account_id.artifact_id"
                                        + "             AND attr_account_id.attribute_type_id = " + BlackboardAttribute.ATTRIBUTE_TYPE.TSK_ID.getTypeID()
                                        + "         AND attr_account_id.value_text = '" + accountUniqueID + "'"
                                        + " WHERE artifacts.artifact_type_id = " + BlackboardArtifact.ARTIFACT_TYPE.TSK_ACCOUNT.getTypeID()
                                        + " AND attr_account_type.attribute_type_id = " + BlackboardAttribute.ATTRIBUTE_TYPE.TSK_ACCOUNT_TYPE.getTypeID()
                                        + " AND attr_account_type.value_text = '" + accountType.getTypeName() + "'"
                                        + " AND artifacts.obj_id = " + sourceFile.getId(); //NON-NLS

                        rs = connection.executeQuery(s, queryStr); //NON-NLS
                        if (rs.next()) {
                                BlackboardArtifact.Type bbartType = db.getArtifactType(rs.getInt("artifact_type_id"));

                                accountArtifact = new BlackboardArtifact(db, rs.getLong("artifact_id"), rs.getLong("obj_id"), rs.getLong("artifact_obj_id"), rs.getLong("data_source_obj_id"),
                                                bbartType.getTypeID(), bbartType.getTypeName(), bbartType.getDisplayName(),
                                                BlackboardArtifact.ReviewStatus.withID(rs.getInt("review_status_id")));
                        }
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }

                return accountArtifact;
        }

        // NOTE: Full name given for Type for doxygen linking
        public org.sleuthkit.datamodel.Account.Type getAccountType(String accountTypeName) throws TskCoreException {
                if (this.typeNameToAccountTypeMap.containsKey(accountTypeName)) {
                        return this.typeNameToAccountTypeMap.get(accountTypeName);
                }

                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, "SELECT account_type_id, type_name, display_name FROM account_types WHERE type_name = '" + accountTypeName + "'"); //NON-NLS
                        Account.Type accountType = null;
                        if (rs.next()) {
                                accountType = new Account.Type(accountTypeName, rs.getString("display_name"));
                                this.accountTypeToTypeIdMap.put(accountType, rs.getInt("account_type_id"));
                                this.typeNameToAccountTypeMap.put(accountTypeName, accountType);
                        }
                        return accountType;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account type id", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        private void addAccountsRelationship(long account1_id, long account2_id, BlackboardArtifact relationshipaArtifact, Relationship.Type relationshipType, long dateTime) throws TskCoreException {
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseWriteLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        String dateTimeValStr = (dateTime > 0) ? Long.toString(dateTime) : "NULL";

                        connection.beginTransaction();
                        s = connection.createStatement();
                        String query = "INTO account_relationships (account1_id, account2_id, relationship_source_obj_id, date_time, relationship_type, data_source_obj_id  ) "
                                        + "VALUES ( " + account1_id + ", " + account2_id + ", " + relationshipaArtifact.getId() + ", " + dateTimeValStr + ", " + relationshipType.getTypeID() + ", " + relationshipaArtifact.getDataSourceObjectID() + ")";
                        switch (db.getDatabaseType()) {
                                case POSTGRESQL:
                                        query = "INSERT " + query + " ON CONFLICT DO NOTHING";
                                        break;
                                case SQLITE:
                                        query = "INSERT OR IGNORE " + query;
                                        break;
                                default:
                                        throw new TskCoreException("Unknown DB Type: " + db.getDatabaseType().name());
                        }
                        s.execute(query); //NON-NLS
                        connection.commitTransaction();
                } catch (SQLException ex) {
                        connection.rollbackTransaction();
                        throw new TskCoreException("Error adding accounts relationship", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseWriteLock();
                }
        }

        public List<AccountDeviceInstance> getAccountDeviceInstancesWithRelationships(CommunicationsFilter filter) throws TskCoreException {
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();

                        //set up applicable filters 
                        Set<String> applicableInnerQueryFilters = new HashSet<String>(Arrays.asList(
                                        CommunicationsFilter.DateRangeFilter.class.getName(),
                                        CommunicationsFilter.DeviceFilter.class.getName(),
                                        CommunicationsFilter.RelationshipTypeFilter.class.getName()
                        ));
                        String relationshipFilterSQL = getCommunicationsFilterSQL(filter, applicableInnerQueryFilters);

                        String relationshipLimitSQL = getMostRecentFilterLimitSQL(filter);

                        String relTblfilterQuery
                                        = "SELECT * "
                                        + "FROM account_relationships as relationships"
                                        + (relationshipFilterSQL.isEmpty() ? "" : " WHERE " + relationshipFilterSQL)
                                        + (relationshipLimitSQL.isEmpty() ? "" : relationshipLimitSQL);

                        String uniqueAccountQueryTemplate
                                        = " SELECT %1$1s as account_id,"
                                        + " data_source_obj_id"
                                        + " FROM ( " + relTblfilterQuery + ")AS %2$s";

                        String relationshipTableFilterQuery1 = String.format(uniqueAccountQueryTemplate, "account1_id", "union_query_1");
                        String relationshipTableFilterQuery2 = String.format(uniqueAccountQueryTemplate, "account2_id", "union_query_2");

                        //this query groups by account_id and data_source_obj_id across both innerQueries
                        String uniqueAccountQuery
                                        = "SELECT DISTINCT account_id, data_source_obj_id"
                                        + " FROM ( " + relationshipTableFilterQuery1 + " UNION " + relationshipTableFilterQuery2 + " ) AS inner_union"
                                        + " GROUP BY account_id, data_source_obj_id";

                        // set up applicable filters
                        Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                        CommunicationsFilter.AccountTypeFilter.class.getName()
                        ));

                        String accountTypeFilterSQL = getCommunicationsFilterSQL(filter, applicableFilters);

                        String queryStr
                                        = //account info
                                        " accounts.account_id AS account_id,"
                                        + " accounts.account_unique_identifier AS account_unique_identifier,"
                                        //account type info
                                        + " account_types.type_name AS type_name,"
                                        //Account device instance info
                                        + " data_source_info.device_id AS device_id"
                                        + " FROM ( " + uniqueAccountQuery + " ) AS account_device_instances"
                                        + " JOIN accounts AS accounts"
                                        + "             ON accounts.account_id = account_device_instances.account_id"
                                        + " JOIN account_types AS account_types"
                                        + "             ON accounts.account_type_id = account_types.account_type_id"
                                        + " JOIN data_source_info AS data_source_info"
                                        + "             ON account_device_instances.data_source_obj_id = data_source_info.obj_id"
                                        + (accountTypeFilterSQL.isEmpty() ? "" : " WHERE " + accountTypeFilterSQL);

                        switch (db.getDatabaseType()) {
                                case POSTGRESQL:
                                        queryStr = "SELECT DISTINCT ON ( accounts.account_id, data_source_info.device_id) " + queryStr;
                                        break;
                                case SQLITE:
                                        queryStr = "SELECT " + queryStr + " GROUP BY accounts.account_id, data_source_info.device_id";
                                        break;
                                default:
                                        throw new TskCoreException("Unknown DB Type: " + db.getDatabaseType().name());
                        }

                        rs = connection.executeQuery(s, queryStr); //NON-NLS
                        ArrayList<AccountDeviceInstance> accountDeviceInstances = new ArrayList<AccountDeviceInstance>();
                        while (rs.next()) {
                                long account_id = rs.getLong("account_id");
                                String deviceID = rs.getString("device_id");
                                final String type_name = rs.getString("type_name");
                                final String account_unique_identifier = rs.getString("account_unique_identifier");

                                Account.Type accountType = typeNameToAccountTypeMap.get(type_name);
                                Account account = new Account(account_id, accountType, account_unique_identifier);
                                accountDeviceInstances.add(new AccountDeviceInstance(account, deviceID));
                        }

                        return accountDeviceInstances;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account device instances. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public Map<AccountPair, Long> getRelationshipCountsPairwise(Set<AccountDeviceInstance> accounts, CommunicationsFilter filter) throws TskCoreException {

                Set<Long> accountIDs = new HashSet<Long>();
                Set<String> accountDeviceIDs = new HashSet<String>();
                for (AccountDeviceInstance adi : accounts) {
                        accountIDs.add(adi.getAccount().getAccountID());
                        accountDeviceIDs.add("'" + adi.getDeviceId() + "'");
                }
                //set up applicable filters 
                Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.DateRangeFilter.class.getName(),
                                CommunicationsFilter.DeviceFilter.class.getName(),
                                CommunicationsFilter.RelationshipTypeFilter.class.getName()
                ));

                String accountIDsCSL = StringUtils.buildCSVString(accountIDs);
                String accountDeviceIDsCSL = StringUtils.buildCSVString(accountDeviceIDs);
                String filterSQL = getCommunicationsFilterSQL(filter, applicableFilters);

                final String queryString
                                = " SELECT  count(DISTINCT relationships.relationship_source_obj_id) AS count," //realtionship count
                                + "             data_source_info.device_id AS device_id,"
                                //account 1 info
                                + "             accounts1.account_id AS account1_id,"
                                + "             accounts1.account_unique_identifier AS account1_unique_identifier,"
                                + "             account_types1.type_name AS type_name1,"
                                + "             account_types1.display_name AS display_name1,"
                                //account 2 info
                                + "             accounts2.account_id AS account2_id,"
                                + "             accounts2.account_unique_identifier AS account2_unique_identifier,"
                                + "             account_types2.type_name AS type_name2,"
                                + "             account_types2.display_name AS display_name2"
                                + " FROM account_relationships AS relationships"
                                + "     JOIN data_source_info AS data_source_info"
                                + "             ON relationships.data_source_obj_id = data_source_info.obj_id "
                                //account1 aliases
                                + "     JOIN accounts AS accounts1       "
                                + "             ON accounts1.account_id = relationships.account1_id"
                                + "     JOIN account_types AS account_types1"
                                + "             ON accounts1.account_type_id = account_types1.account_type_id"
                                //account2 aliases
                                + "     JOIN accounts AS accounts2       "
                                + "             ON accounts2.account_id = relationships.account2_id"
                                + "     JOIN account_types AS account_types2"
                                + "             ON accounts2.account_type_id = account_types2.account_type_id"
                                + " WHERE (( relationships.account1_id IN (" + accountIDsCSL + ")) "
                                + "             AND ( relationships.account2_id IN ( " + accountIDsCSL + " ))"
                                + "             AND ( data_source_info.device_id IN (" + accountDeviceIDsCSL + "))) "
                                + (filterSQL.isEmpty() ? "" : " AND " + filterSQL)
                                + "  GROUP BY data_source_info.device_id, "
                                + "             accounts1.account_id, "
                                + "             account_types1.type_name, "
                                + "             account_types1.display_name, "
                                + "             accounts2.account_id, "
                                + "             account_types2.type_name, "
                                + "             account_types2.display_name";
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                Map<AccountPair, Long> results = new HashMap<AccountPair, Long>();

                try {
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, queryString); //NON-NLS

                        while (rs.next()) {
                                //make account 1
                                Account.Type type1 = new Account.Type(rs.getString("type_name1"), rs.getString("display_name1"));
                                AccountDeviceInstance adi1 = new AccountDeviceInstance(new Account(rs.getLong("account1_id"), type1,
                                                rs.getString("account1_unique_identifier")),
                                                rs.getString("device_id"));

                                //make account 2
                                Account.Type type2 = new Account.Type(rs.getString("type_name2"), rs.getString("display_name2"));
                                AccountDeviceInstance adi2 = new AccountDeviceInstance(new Account(rs.getLong("account2_id"), type2,
                                                rs.getString("account2_unique_identifier")),
                                                rs.getString("device_id"));

                                AccountPair relationshipKey = new AccountPair(adi1, adi2);
                                long count = rs.getLong("count");

                                //merge counts for relationships that have the accounts flipped.
                                Long oldCount = results.get(relationshipKey);
                                if (oldCount != null) {
                                        count += oldCount;
                                }
                                results.put(relationshipKey, count);
                        }
                        return results;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting relationships between accounts. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public long getRelationshipSourcesCount(AccountDeviceInstance accountDeviceInstance, CommunicationsFilter filter) throws TskCoreException {

                long account_id = accountDeviceInstance.getAccount().getAccountID();

                // Get the list of Data source objects IDs correpsonding to this DeviceID.
                String datasourceObjIdsCSV = StringUtils.buildCSVString(
                                db.getDataSourceObjIds(accountDeviceInstance.getDeviceId()));

                // set up applicable filters
                Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.RelationshipTypeFilter.class.getName(),
                                CommunicationsFilter.DateRangeFilter.class.getName()
                ));
                String filterSQL = getCommunicationsFilterSQL(filter, applicableFilters);

                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();

                        String innerQuery = " account_relationships AS relationships";
                        String limitStr = getMostRecentFilterLimitSQL(filter);

                        if (!limitStr.isEmpty()) {
                                innerQuery = "(SELECT * FROM account_relationships as relationships " + limitStr + ") as relationships";
                        }

                        String queryStr
                                        = "SELECT count(DISTINCT relationships.relationship_source_obj_id) as count "
                                        + "     FROM" + innerQuery
                                        + " WHERE relationships.data_source_obj_id IN ( " + datasourceObjIdsCSV + " )"
                                        + " AND ( relationships.account1_id = " + account_id
                                        + "      OR  relationships.account2_id = " + account_id + " )"
                                        + (filterSQL.isEmpty() ? "" : " AND " + filterSQL);

                        rs = connection.executeQuery(s, queryStr); //NON-NLS
                        rs.next();
                        return (rs.getLong("count"));
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting relationships count for account device instance. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public Set<Content> getRelationshipSources(Set<AccountDeviceInstance> accountDeviceInstanceList, CommunicationsFilter filter) throws TskCoreException {

                if (accountDeviceInstanceList.isEmpty()) {
                        //log this?
                        return Collections.emptySet();
                }

                Map<Long, Set<Long>> accountIdToDatasourceObjIdMap = new HashMap<Long, Set<Long>>();
                for (AccountDeviceInstance accountDeviceInstance : accountDeviceInstanceList) {
                        long accountID = accountDeviceInstance.getAccount().getAccountID();
                        List<Long> dataSourceObjIds = db.getDataSourceObjIds(accountDeviceInstance.getDeviceId());

                        if (accountIdToDatasourceObjIdMap.containsKey(accountID)) {
                                accountIdToDatasourceObjIdMap.get(accountID).addAll(dataSourceObjIds);
                        } else {
                                accountIdToDatasourceObjIdMap.put(accountID, new HashSet<Long>(dataSourceObjIds));
                        }
                }

                List<String> adiSQLClauses = new ArrayList<String>();
                for (Map.Entry<Long, Set<Long>> entry : accountIdToDatasourceObjIdMap.entrySet()) {
                        final Long accountID = entry.getKey();
                        String datasourceObjIdsCSV = StringUtils.buildCSVString(entry.getValue());

                        adiSQLClauses.add(
                                        "( ( relationships.data_source_obj_id IN ( " + datasourceObjIdsCSV + " ) )"
                                        + " AND ( relationships.account1_id = " + accountID
                                        + " OR relationships.account2_id = " + accountID + " ) )"
                        );
                }
                String adiSQLClause = StringUtils.joinAsStrings(adiSQLClauses, " OR ");

                // set up applicable filters
                Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.RelationshipTypeFilter.class
                                                .getName(),
                                CommunicationsFilter.DateRangeFilter.class
                                                .getName()
                ));
                String filterSQL = getCommunicationsFilterSQL(filter, applicableFilters);

                String limitQuery = " account_relationships AS relationships";
                String limitStr = getMostRecentFilterLimitSQL(filter);
                if (!limitStr.isEmpty()) {
                        limitQuery = "(SELECT * FROM account_relationships as relationships " + limitStr + ") as relationships";
                }

                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();
                        String queryStr
                                        = "SELECT DISTINCT artifacts.artifact_id AS artifact_id,"
                                        + " artifacts.obj_id AS obj_id,"
                                        + " artifacts.artifact_obj_id AS artifact_obj_id,"
                                        + " artifacts.data_source_obj_id AS data_source_obj_id, "
                                        + " artifacts.artifact_type_id AS artifact_type_id, "
                                        + " artifacts.review_status_id AS review_status_id  "
                                        + " FROM blackboard_artifacts as artifacts"
                                        + " JOIN " + limitQuery
                                        + "     ON artifacts.artifact_obj_id = relationships.relationship_source_obj_id"
                                        // append sql to restrict search to specified account device instances 
                                        + " WHERE (" + adiSQLClause + " )"
                                        // plus other filters
                                        + (filterSQL.isEmpty() ? "" : " AND (" + filterSQL + " )");

                        rs = connection.executeQuery(s, queryStr); //NON-NLS
                        Set<Content> relationshipSources = new HashSet<Content>();
                        while (rs.next()) {
                                BlackboardArtifact.Type bbartType = db.getArtifactType(rs.getInt("artifact_type_id"));
                                relationshipSources.add(new BlackboardArtifact(db, rs.getLong("artifact_id"),
                                                rs.getLong("obj_id"), rs.getLong("artifact_obj_id"),
                                                rs.getLong("data_source_obj_id"), bbartType.getTypeID(),
                                                bbartType.getTypeName(), bbartType.getDisplayName(),
                                                BlackboardArtifact.ReviewStatus.withID(rs.getInt("review_status_id"))));
                        }

                        return relationshipSources;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting relationships for account. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public List<AccountDeviceInstance> getRelatedAccountDeviceInstances(AccountDeviceInstance accountDeviceInstance, CommunicationsFilter filter) throws TskCoreException {
                final List<Long> dataSourceObjIds
                                = getSleuthkitCase().getDataSourceObjIds(accountDeviceInstance.getDeviceId());

                //set up applicable filters 
                Set<String> applicableInnerQueryFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.DateRangeFilter.class.getName(),
                                CommunicationsFilter.DeviceFilter.class.getName(),
                                CommunicationsFilter.RelationshipTypeFilter.class.getName()
                ));

                String innerQueryfilterSQL = getCommunicationsFilterSQL(filter, applicableInnerQueryFilters);

                String innerQueryTemplate
                                = " SELECT %1$1s as account_id,"
                                + "               data_source_obj_id"
                                + " FROM account_relationships as relationships"
                                + " WHERE %2$1s = " + accountDeviceInstance.getAccount().getAccountID() + ""
                                + " AND data_source_obj_id IN (" + StringUtils.buildCSVString(dataSourceObjIds) + ")"
                                + (innerQueryfilterSQL.isEmpty() ? "" : " AND " + innerQueryfilterSQL);

                String innerQuery1 = String.format(innerQueryTemplate, "account1_id", "account2_id");
                String innerQuery2 = String.format(innerQueryTemplate, "account2_id", "account1_id");

                //this query groups by account_id and data_source_obj_id across both innerQueries
                String combinedInnerQuery
                                = "SELECT account_id, data_source_obj_id "
                                + " FROM ( " + innerQuery1 + " UNION " + innerQuery2 + " ) AS  inner_union"
                                + " GROUP BY account_id, data_source_obj_id";

                // set up applicable filters
                Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.AccountTypeFilter.class.getName()
                ));

                String filterSQL = getCommunicationsFilterSQL(filter, applicableFilters);

                String queryStr
                                = //account info
                                " accounts.account_id AS account_id,"
                                + " accounts.account_unique_identifier AS account_unique_identifier,"
                                //account type info
                                + " account_types.type_name AS type_name,"
                                //Account device instance info
                                + " data_source_info.device_id AS device_id"
                                + " FROM ( " + combinedInnerQuery + " ) AS account_device_instances"
                                + " JOIN accounts AS accounts"
                                + "             ON accounts.account_id = account_device_instances.account_id"
                                + " JOIN account_types AS account_types"
                                + "             ON accounts.account_type_id = account_types.account_type_id"
                                + " JOIN data_source_info AS data_source_info"
                                + "             ON account_device_instances.data_source_obj_id = data_source_info.obj_id"
                                + (filterSQL.isEmpty() ? "" : " WHERE " + filterSQL);

                switch (db.getDatabaseType()) {
                        case POSTGRESQL:
                                queryStr = "SELECT DISTINCT ON ( accounts.account_id, data_source_info.device_id) " + queryStr;
                                break;
                        case SQLITE:
                                queryStr = "SELECT " + queryStr + " GROUP BY accounts.account_id, data_source_info.device_id";
                                break;
                        default:
                                throw new TskCoreException("Unknown DB Type: " + db.getDatabaseType().name());
                }

                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;

                try {
                        s = connection.createStatement();

                        rs = connection.executeQuery(s, queryStr); //NON-NLS
                        ArrayList<AccountDeviceInstance> accountDeviceInstances = new ArrayList<AccountDeviceInstance>();
                        while (rs.next()) {
                                long account_id = rs.getLong("account_id");
                                String deviceID = rs.getString("device_id");
                                final String type_name = rs.getString("type_name");
                                final String account_unique_identifier = rs.getString("account_unique_identifier");

                                Account.Type accountType = typeNameToAccountTypeMap.get(type_name);
                                Account account = new Account(account_id, accountType, account_unique_identifier);
                                accountDeviceInstances.add(new AccountDeviceInstance(account, deviceID));
                        }

                        return accountDeviceInstances;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account device instances. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public List<Content> getRelationshipSources(AccountDeviceInstance account1, AccountDeviceInstance account2, CommunicationsFilter filter) throws TskCoreException {

                //set up applicable filters 
                Set<String> applicableFilters = new HashSet<String>(Arrays.asList(
                                CommunicationsFilter.DateRangeFilter.class.getName(),
                                CommunicationsFilter.DeviceFilter.class.getName(),
                                CommunicationsFilter.RelationshipTypeFilter.class.getName()
                ));

                String limitQuery = " account_relationships AS relationships";
                String limitStr = getMostRecentFilterLimitSQL(filter);
                if (!limitStr.isEmpty()) {
                        limitQuery = "(SELECT * FROM account_relationships as relationships " + limitStr + ") as relationships";
                }

                String filterSQL = getCommunicationsFilterSQL(filter, applicableFilters);
                final String queryString = "SELECT artifacts.artifact_id AS artifact_id,"
                                + "             artifacts.obj_id AS obj_id,"
                                + "             artifacts.artifact_obj_id AS artifact_obj_id,"
                                + "             artifacts.data_source_obj_id AS data_source_obj_id,"
                                + "             artifacts.artifact_type_id AS artifact_type_id,"
                                + "             artifacts.review_status_id AS review_status_id"
                                + " FROM blackboard_artifacts AS artifacts"
                                + "     JOIN " + limitQuery
                                + "             ON artifacts.artifact_obj_id = relationships.relationship_source_obj_id"
                                + " WHERE (( relationships.account1_id = " + account1.getAccount().getAccountID()
                                + " AND relationships.account2_id  = " + account2.getAccount().getAccountID()
                                + " ) OR (        relationships.account2_id = " + account1.getAccount().getAccountID()
                                + " AND relationships.account1_id =" + account2.getAccount().getAccountID() + " ))"
                                + (filterSQL.isEmpty() ? "" : " AND " + filterSQL);
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;
                try {
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, queryString); //NON-NLS

                        ArrayList<Content> artifacts = new ArrayList<Content>();
                        while (rs.next()) {
                                BlackboardArtifact.Type bbartType = db.getArtifactType(rs.getInt("artifact_type_id"));
                                artifacts.add(new BlackboardArtifact(db, rs.getLong("artifact_id"), rs.getLong("obj_id"), rs.getLong("artifact_obj_id"), rs.getLong("data_source_obj_id"),
                                                bbartType.getTypeID(), bbartType.getTypeName(), bbartType.getDisplayName(),
                                                BlackboardArtifact.ReviewStatus.withID(rs.getInt("review_status_id"))));
                        }

                        return artifacts;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting relationships between accounts. " + ex.getMessage(), ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public List<AccountFileInstance> getAccountFileInstances(Account account) throws TskCoreException {
                List<AccountFileInstance> accountFileInstanceList = new ArrayList<>();

                List<BlackboardArtifact> artifactList = getSleuthkitCase().getBlackboardArtifacts(BlackboardArtifact.ARTIFACT_TYPE.TSK_ACCOUNT, BlackboardAttribute.ATTRIBUTE_TYPE.TSK_ID, account.getTypeSpecificID());

                if (artifactList != null && !artifactList.isEmpty()) {
                        for (BlackboardArtifact artifact : artifactList) {
                                accountFileInstanceList.add(new AccountFileInstance(artifact, account));
                        }
                }

                if (!accountFileInstanceList.isEmpty()) {
                        return accountFileInstanceList;
                } else {
                        return null;
                }
        }

        public List<Account.Type> getAccountTypesInUse() throws TskCoreException {
                CaseDbConnection connection = db.getConnection();
                db.acquireSingleUserCaseReadLock();
                Statement s = null;
                ResultSet rs = null;
                List<Account.Type> inUseAccounts = new ArrayList<>();

                try {
                        String query = "SELECT DISTINCT accounts.account_type_id, type_name, display_name FROM accounts JOIN account_types ON accounts.account_type_id = account_types.account_type_id";
                        s = connection.createStatement();
                        rs = connection.executeQuery(s, query); //NON-NLS
                        Account.Type accountType = null;
                        while (rs.next()) {
                                String accountTypeName = rs.getString("type_name");
                                accountType = this.typeNameToAccountTypeMap.get(accountTypeName);

                                if (accountType == null) {
                                        accountType = new Account.Type(accountTypeName, rs.getString("display_name"));
                                        this.accountTypeToTypeIdMap.put(accountType, rs.getInt("account_type_id"));
                                }

                                inUseAccounts.add(accountType);
                        }
                        return inUseAccounts;
                } catch (SQLException ex) {
                        throw new TskCoreException("Error getting account type id", ex);
                } finally {
                        closeResultSet(rs);
                        closeStatement(s);
                        connection.close();
                        db.releaseSingleUserCaseReadLock();
                }
        }

        public List<Account> getAccountsRelatedToArtifact(BlackboardArtifact artifact) throws TskCoreException {
                if (artifact == null) {
                        throw new IllegalArgumentException("null arugment passed to getAccountsRelatedToArtifact");
                }

                List<Account> accountList = new ArrayList<>();
                try (CaseDbConnection connection = db.getConnection()) {
                        db.acquireSingleUserCaseReadLock();
                        try {
                                // In order to get a list of all the unique accounts in a relationship with the given aritfact
                                // we must first union a list of the unique account1_id in the relationship with artifact
                                // then the unique account2_id (inner select with union).  The outter select assures the list
                                // of the inner select only contains unique accounts.
                                String query = String.format("SELECT DISTINCT (account_id), account_type_id, account_unique_identifier"
                                                + "     FROM ("
                                                + " SELECT DISTINCT (account_id), account_type_id, account_unique_identifier"
                                                + " FROM accounts"
                                                + " JOIN account_relationships ON account1_id = account_id"
                                                + " WHERE relationship_source_obj_id = %d"
                                                + " UNION "
                                                + " SELECT DISTINCT (account_id), account_type_id, account_unique_identifier"
                                                + " FROM accounts"
                                                + " JOIN account_relationships ON account2_id = account_id"
                                                + " WHERE relationship_source_obj_id = %d) AS unionOfRelationships", artifact.getId(), artifact.getId());
                                try (Statement stmt = connection.createStatement(); ResultSet rs = stmt.executeQuery(query)) {
                                        while (rs.next()) {
                                                Account.Type accountType = null;
                                                int accountTypeId = rs.getInt("account_type_id");
                                                for (Map.Entry<Account.Type, Integer> entry : accountTypeToTypeIdMap.entrySet()) {
                                                        if (entry.getValue() == accountTypeId) {
                                                                accountType = entry.getKey();
                                                                break;
                                                        }
                                                }

                                                accountList.add(new Account(rs.getInt("account_id"), accountType, rs.getString("account_unique_identifier")));
                                        }
                                } catch (SQLException ex) {
                                        throw new TskCoreException("Unable to get account list for give artifact " + artifact.getId(), ex);
                                }

                        } finally {
                                db.releaseSingleUserCaseReadLock();
                        }
                }

                return accountList;
        }

        int getAccountTypeId(Account.Type accountType) {
                if (accountTypeToTypeIdMap.containsKey(accountType)) {
                        return accountTypeToTypeIdMap.get(accountType);
                }

                return 0;
        }

        private String normalizeAccountID(Account.Type accountType, String accountUniqueID) throws InvalidAccountIDException {

                if (accountUniqueID == null || accountUniqueID.isEmpty()) {
                        throw new InvalidAccountIDException("Account id is null or empty.");
                }

                String normalizedAccountID;
                if (accountType.equals(Account.Type.PHONE)) {
                        normalizedAccountID = CommunicationsUtils.normalizePhoneNum(accountUniqueID);
                } else if (accountType.equals(Account.Type.EMAIL)) {
                        normalizedAccountID = CommunicationsUtils.normalizeEmailAddress(accountUniqueID);
                } else {
                        normalizedAccountID = accountUniqueID.toLowerCase().trim();
                }

                return normalizedAccountID;
        }

        private String getCommunicationsFilterSQL(CommunicationsFilter commFilter, Set<String> applicableFilters) {
                if (null == commFilter || commFilter.getAndFilters().isEmpty()) {
                        return "";
                }

                String sqlStr = "";
                StringBuilder sqlSB = new StringBuilder();
                boolean first = true;
                for (CommunicationsFilter.SubFilter subFilter : commFilter.getAndFilters()) {

                        // If the filter is applicable
                        if (applicableFilters.contains(subFilter.getClass().getName())) {
                                String subfilterSQL = subFilter.getSQL(this);
                                if (!subfilterSQL.isEmpty()) {
                                        if (first) {
                                                first = false;
                                        } else {
                                                sqlSB.append(" AND ");
                                        }
                                        sqlSB.append("( ");
                                        sqlSB.append(subfilterSQL);
                                        sqlSB.append(" )");
                                }
                        }
                }

                if (!sqlSB.toString().isEmpty()) {
                        sqlStr = "( " + sqlSB.toString() + " )";
                }
                return sqlStr;
        }

        private String getMostRecentFilterLimitSQL(CommunicationsFilter filter) {
                String limitStr = "";

                if (filter != null && !filter.getAndFilters().isEmpty()) {

                        for (CommunicationsFilter.SubFilter subFilter : filter.getAndFilters()) {
                                if (subFilter.getClass().getName().equals(CommunicationsFilter.MostRecentFilter.class.getName())) {
                                        limitStr = subFilter.getSQL(this);
                                        break;
                                }
                        }
                }

                return limitStr;
        }
}