com.ikanow.infinit.e.api.knowledge.aliases.AliasManager.java Source code

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Here is the source code for com.ikanow.infinit.e.api.knowledge.aliases.AliasManager.java

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/*******************************************************************************
 * Copyright 2012, The Infinit.e Open Source Project.
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 * 
 * 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 Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package com.ikanow.infinit.e.api.knowledge.aliases;

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;

import org.apache.log4j.Logger;
import org.bson.types.ObjectId;

import com.ikanow.infinit.e.api.utils.PropertiesManager;
import com.ikanow.infinit.e.data_model.store.MongoDbManager;
import com.ikanow.infinit.e.data_model.store.social.sharing.SharePojo;
import com.ikanow.infinit.e.data_model.store.social.sharing.SharePojo.ShareCommunityPojo;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;

public class AliasManager {

    private static final Logger logger = Logger.getLogger(AliasManager.class);

    private static AliasManager _myself = null;
    private static boolean _bFirstTime = true;

    public static AliasManager getAliasManager() {

        synchronized (AliasManager.class) {
            if (_bFirstTime) {
                // Check if (beta) aliasing enabled
                PropertiesManager props = new PropertiesManager();
                if (props.getAliasingEnabled()) {
                    if (null == _myself) {
                        logger.debug("Initialized alias manager");

                        return (_myself = new AliasManager());
                    }
                }
                _bFirstTime = false;
            }
        } //TOTEST
        return _myself;
    }

    ////////////////////////////////////////////////////////////////////////////////////////////

    // Returns null if there's no active alias lookup table
    // (isn't null in the underlying structure)

    public synchronized AliasLookupTable getAliasLookupTable(String communityListStr, String[] communityStrArray,
            List<ObjectId> communityList, String userIdStr) {

        // 1. Normalize input args
        if ((null == communityListStr) || (communityListStr.startsWith("*"))) {
            StringBuffer sb = new StringBuffer();
            if (null != communityStrArray) {
                for (String sid : communityStrArray) {
                    sb.append(sid);
                    sb.append(",");
                }
            } else { // communityList != null
                for (ObjectId oid : communityList) {
                    sb.append(oid.toString());
                    sb.append(",");
                }
            }
            if (sb.length() > 0) {
                sb.setLength(sb.length() - 1);
            }
            communityListStr = sb.toString();
        } //TESTED
        if (null == communityList) {
            if (null == communityStrArray) {
                communityStrArray = communityListStr.split("\\.");
            }
            communityList = new ArrayList<ObjectId>(communityStrArray.length);
            for (String s : communityStrArray) {
                try {
                    communityList.add(new ObjectId(s));
                } catch (Exception e) {
                } // just carry on
            }
        } //TOTEST

        // 2. Get alias table

        AliasLookupTable table = _aliasLookups.get(communityListStr);
        Date now = new Date();

        // 3. Check alias table refresh

        boolean bRefresh = true;

        if (null != table) {
            // If it exists, check if it needs to be refreshed (check share modified times if >1 minute say)
            Date tableLastMod = table.getLastModified();
            if (null != tableLastMod) {
                if (now.getTime() - tableLastMod.getTime() <= 60000) { // less than a minute ago
                    bRefresh = false;
                }
            }
            if (bRefresh) { // Check shares to see if we really need to refresh

                logger.debug("Alias table exists, checking for refresh: " + communityListStr);

                BasicDBObject query = new BasicDBObject(SharePojo.type_, "infinite-entity-alias");
                query.put(ShareCommunityPojo.shareQuery_id_, new BasicDBObject(MongoDbManager.in_, communityList));
                query.put(SharePojo.endorsed_, new BasicDBObject(MongoDbManager.in_, communityList));
                BasicDBObject fields = new BasicDBObject(SharePojo.modified_, 1);
                DBCursor dbc = MongoDbManager.getSocial().getShare().find(query, fields);

                if (dbc.count() == table.getNumAliasShares()) { // easy answer is out!
                    bRefresh = false;
                    for (DBObject dbo : dbc) {
                        Date date = (Date) dbo.get(SharePojo.modified_);
                        if ((date != null) && (date.getTime() > tableLastMod.getTime())) {
                            logger.debug("Alias: change in date for " + dbo.get(SharePojo._id_) + ": " + date);
                            bRefresh = true;
                            break;
                        }
                    }
                } //TOTEST
                else {
                    logger.debug("Alias: change in #shares, now: " + dbc.count() + " vs prev: "
                            + table.getNumAliasShares());
                }
            }
        } //TESTED 
        else {
            table = new AliasLookupTable();
            _aliasLookups.put(communityListStr, table);
        }

        // 4. Perform alias table refresh

        if (bRefresh) {

            BasicDBObject query = new BasicDBObject(SharePojo.type_, "infinite-entity-alias");
            query.put(ShareCommunityPojo.shareQuery_id_, new BasicDBObject(MongoDbManager.in_, communityList));
            query.put(SharePojo.endorsed_, new BasicDBObject(MongoDbManager.in_, communityList));

            List<SharePojo> aliasShares = SharePojo.listFromDb(MongoDbManager.getSocial().getShare().find(query),
                    SharePojo.listType());

            if (null != aliasShares) {
                logger.debug("Refresh/build alias table " + communityListStr + ": " + aliasShares.size());
            } else {
                logger.debug("Clear alias table " + communityListStr);
                aliasShares = new ArrayList<SharePojo>();
            }
            table.buildOrUpdateAliasTable(aliasShares, userIdStr);

        } //TESTED

        return table.isEmpty() ? null : table;

    }//TOTEST (just the communityList == null case)

    ////////////////////////////////////////////////////////////////////////////////////////////

    // State

    private HashMap<String, AliasLookupTable> _aliasLookups = new HashMap<String, AliasLookupTable>();

}