com.linuxbox.util.queueservice.mongodb.JavaQueueService.java Source code

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Here is the source code for com.linuxbox.util.queueservice.mongodb.JavaQueueService.java

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/*******************************************************************************
 * Copyright 2013 The Linux Box Corporation.
 *
 * This file is part of Enkive CE (Community Edition).
 *
 * Enkive CE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * Enkive CE 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 Enkive CE. If not, see
 * <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package com.linuxbox.util.queueservice.mongodb;

import java.util.Date;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.NoSuchElementException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.linuxbox.enkive.docstore.DocStoreService;
import com.linuxbox.util.queueservice.AbstractQueueEntry;
import com.linuxbox.util.queueservice.QueueEntry;
import com.linuxbox.util.queueservice.QueueService;
import com.linuxbox.util.queueservice.QueueServiceException;

public class JavaQueueService implements QueueService {
    protected static final Log LOGGER = LogFactory.getLog("com.linuxbox.util.queueservice.mongodb");

    private LinkedHashMap<String, LinkedList<QueueEntry>> queue;
    private DocStoreService docStoreService;
    private LinkedList<QueueEntry> dequeued;

    public JavaQueueService() {
        queue = new LinkedHashMap<String, LinkedList<QueueEntry>>();
        dequeued = new LinkedList<QueueEntry>();
    }

    public void setDocStoreService(DocStoreService service) {
        this.docStoreService = service;
    }

    /**
     * Pre-fill our queue with any messages that have not been indexed yet.
     */
    @Override
    public void startup() throws QueueServiceException {
        String identifier;
        while ((identifier = docStoreService.nextUnindexed()) != null) {
            enqueue(identifier);
        }
    }

    @Override
    public void shutdown() throws QueueServiceException {
        // empty
    }

    @Override
    public void enqueue(String identifier) throws QueueServiceException {
        enqueue(identifier, -1, null);
    }

    @Override
    public synchronized void enqueue(String identifier, int shardKey, Object note) throws QueueServiceException {
        QueueEntry entry = new AbstractQueueEntry(new Date(), identifier, note, shardKey);
        LinkedList<QueueEntry> list = queue.get(identifier);
        if (list == null) {
            list = new LinkedList<QueueEntry>();
            queue.put(identifier, list);
        }
        list.addLast(entry);
    }

    @Override
    public synchronized QueueEntry dequeue() throws QueueServiceException {
        String identifier;
        try {
            identifier = queue.keySet().iterator().next();
        } catch (NoSuchElementException e) {
            return (null);
        }

        return (dequeue(identifier));
    }

    @Override
    public synchronized QueueEntry dequeue(String identifier) throws QueueServiceException {
        LinkedList<QueueEntry> list = queue.get(identifier);
        if (list == null) {
            return null;
        }
        QueueEntry entry = list.removeFirst();
        if (list.peek() == null) {
            queue.remove(identifier);
        }
        dequeued.push(entry);
        return (entry);
    }

    @Override
    public QueueEntry dequeueByShardKey(int rangeLow, int rangeHigh) throws QueueServiceException {
        return (this.dequeue());
    }

    @Override
    public void finishEntry(QueueEntry entry) throws QueueServiceException {
        if (!dequeued.remove(entry)) {
            throw new QueueServiceException("No dequeued entry");
        }
    }

    @Override
    public void markEntryAsError(QueueEntry entry) throws QueueServiceException {
        if (!dequeued.remove(entry)) {
            throw new QueueServiceException("No dequeued entry");
        }
    }
}