mongo-java-driver/examples/ReadOplog.java at master · alphaadidas/mongo-java-driver · GitHub

46 lines (36 loc) · 1.35 KB

// ReadOplog.java

package examples;

import com.mongodb.*;

import org.bson.types.*;

import java.util.*;

public class ReadOplog {

public static void main(String[] args)

throws Exception {

Mongo m = new Mongo();

DB local = m.getDB( "local" );

DBCollection oplog = local.getCollection( "oplog.$main" );

DBObject last = null;

{

DBCursor lastCursor = oplog.find().sort( new BasicDBObject( "$natural" , -1 ) ).limit(1);

if ( ! lastCursor.hasNext() ){

System.out.println( "no oplog!" );

return;

}

last = lastCursor.next();

}

BSONTimestamp ts = (BSONTimestamp)last.get("ts");

System.out.println( "starting point: " + ts );

while ( true ){

System.out.println( "starting at ts: " + ts );

DBCursor cursor = oplog.find( new BasicDBObject( "ts" , new BasicDBObject( "$gt" , ts ) ) );

cursor.addOption( Bytes.QUERYOPTION_TAILABLE );

cursor.addOption( Bytes.QUERYOPTION_AWAITDATA );

while ( cursor.hasNext() ){

DBObject x = cursor.next();

ts = (BSONTimestamp)x.get("ts");

System.out.println( "\t" + x );

}

Thread.sleep( 1000 );

}

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