com.torodb.mongodb.repl.oplogreplier.fetcher.StaticOplogReader.java Source code

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Here is the source code for com.torodb.mongodb.repl.oplogreplier.fetcher.StaticOplogReader.java

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/*
 * ToroDB
 * Copyright  2014 8Kdata Technology (www.8kdata.com)
 *
 * This program 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.
 *
 * 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.torodb.mongodb.repl.oplogreplier.fetcher;

import com.google.common.base.Preconditions;
import com.google.common.collect.Iterators;
import com.google.common.net.HostAndPort;
import com.torodb.mongodb.repl.OplogReader;
import com.torodb.mongowp.OpTime;
import com.torodb.mongowp.commands.oplog.OplogOperation;
import com.torodb.mongowp.commands.pojos.IteratorMongoCursor;
import com.torodb.mongowp.commands.pojos.MongoCursor;
import com.torodb.mongowp.exceptions.MongoException;
import com.torodb.mongowp.exceptions.OplogOperationUnsupported;
import com.torodb.mongowp.exceptions.OplogStartMissingException;

import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Function;
import java.util.stream.Collectors;

/**
 *
 */
public class StaticOplogReader implements OplogReader {

    private static final String DATABASE = "local";
    private static final String COLLECTION = "oplog.rs";

    private final HostAndPort hostAndPort;
    private final SortedMap<OpTime, OplogOperation> oplog;
    private final AtomicInteger idProvider = new AtomicInteger();
    private volatile boolean closed = false;

    public StaticOplogReader(Collection<OplogOperation> oplog) {
        this(HostAndPort.fromParts("localhost", 27017), oplog);
    }

    public StaticOplogReader(HostAndPort hostAndPort, Collection<OplogOperation> oplog) {
        this(hostAndPort,
                new TreeMap<>(oplog.stream().collect(Collectors.toMap(o -> o.getOpTime(), Function.identity()))));
    }

    public StaticOplogReader(SortedMap<OpTime, OplogOperation> oplog) {
        this(HostAndPort.fromParts("localhost", 27017), oplog);
    }

    public StaticOplogReader(HostAndPort hostAndPort, SortedMap<OpTime, OplogOperation> oplog) {
        this.hostAndPort = hostAndPort;
        this.oplog = oplog;
    }

    @Override
    public HostAndPort getSyncSource() {
        return hostAndPort;
    }

    @Override
    public MongoCursor<OplogOperation> queryGte(OpTime lastFetchedOpTime) throws MongoException {
        Preconditions.checkState(!closed);

        return new IteratorMongoCursor<>(DATABASE, COLLECTION, idProvider.incrementAndGet(), hostAndPort,
                oplog.tailMap(lastFetchedOpTime).values().iterator());
    }

    @Override
    public OplogOperation getLastOp() throws OplogStartMissingException, OplogOperationUnsupported, MongoException {
        Preconditions.checkState(!closed);
        if (oplog.isEmpty()) {
            throw new OplogStartMissingException(hostAndPort);
        }
        return oplog.get(oplog.lastKey());
    }

    @Override
    public OplogOperation getFirstOp()
            throws OplogStartMissingException, OplogOperationUnsupported, MongoException {
        Preconditions.checkState(!closed);
        if (oplog.isEmpty()) {
            throw new OplogStartMissingException(hostAndPort);
        }
        return oplog.get(oplog.firstKey());
    }

    @Override
    public void close() {
        closed = true;
    }

    @Override
    public boolean isClosed() {
        return closed;
    }

    @Override
    public MongoCursor<OplogOperation> between(OpTime from, boolean includeFrom, OpTime to, boolean includeTo)
            throws OplogStartMissingException, OplogOperationUnsupported, MongoException {
        Preconditions.checkState(!closed);

        Iterator<OplogOperation> iterator = getBetweenIterator(from, includeFrom, to, includeTo);

        return new IteratorMongoCursor<>(DATABASE, COLLECTION, idProvider.incrementAndGet(), hostAndPort, iterator);
    }

    private Iterator<OplogOperation> getBetweenIterator(OpTime from, boolean includeFrom, OpTime to,
            boolean includeTo) {
        OpTime includedFrom;
        OpTime excludedTo;

        if (includeFrom || !oplog.containsKey(from)) {
            includedFrom = from;
        } else { //_from_ is excluded, but subMap includes it!
            SortedMap<OpTime, OplogOperation> tailMap = oplog.tailMap(from);
            if (tailMap.size() > 1) {
                includedFrom = tailMap.keySet().iterator().next();
            } else { //the _from_ key is the only key greater or equal than _from_ and we want to exclude it
                return Collections.emptyIterator();
            }
        }

        Iterator<OplogOperation> excludingIt = oplog.subMap(includedFrom, to).values().iterator();
        if (includeTo) {
            OplogOperation toOp = oplog.get(to);
            if (toOp != null) {
                return Iterators.concat(excludingIt, Collections.singleton(toOp).iterator());
            }
        }
        return excludingIt;
    }

}