Example usage for com.mongodb DBCollection find

Introduction

In this page you can find the example usage for com.mongodb DBCollection find.

Prototype

public DBCursor find(@Nullable final DBObject query, final DBCollectionFindOptions options)

Source Link

Document

Select documents in collection and get a cursor to the selected documents.

Usage

From source file:com.zjy.mongo.input.MongoInputSplit.java

License:Apache License

public DBCursor getCursor() {
    if (this.cursor == null) {
        DBCollection coll;
        if (this.authURI != null) {
            coll = MongoConfigUtil.getCollectionWithAuth(this.inputURI, this.authURI);
        } else {/*from   w w  w  . j  a v  a 2  s. c  o  m*/
            coll = MongoConfigUtil.getCollection(this.inputURI);
        }

        this.cursor = coll.find(this.query, this.fields).sort(this.sort);
        if (this.notimeout) {
            this.cursor.setOptions(Bytes.QUERYOPTION_NOTIMEOUT);
        }
        if (this.min != null) {
            this.cursor.addSpecial("$min", this.min);
        }
        if (this.max != null) {
            this.cursor.addSpecial("$max", this.max);
        }
    }
    return this.cursor;
}

From source file:de.fhg.igd.mongomvcc.impl.MongoDBVMaintenance.java

License:Open Source License

private long[] doFindDanglingCommits(long expiry, TimeUnit unit) {
    long maxTime = getMaxTime(expiry, unit);

    //load all commits which are older than the expiry time. mark them as dangling
    DBCollection collCommits = _db.getDB().getCollection(MongoDBConstants.COLLECTION_COMMITS);
    DBCursor commits = collCommits.find(
            new BasicDBObject(MongoDBConstants.TIMESTAMP,
                    new BasicDBObject("$not", new BasicDBObject("$gte", maxTime))), //also include commits without a timestamp
            new BasicDBObject(MongoDBConstants.ID, 1));
    IdSet danglingCommits = new IdHashSet();
    for (DBObject o : commits) {
        long cid = (Long) o.get(MongoDBConstants.ID);
        danglingCommits.add(cid);//from   www . j av a 2s.co m
    }

    //walk through all branches and eliminate commits which are not dangling
    DBCollection collBranches = _db.getDB().getCollection(MongoDBConstants.COLLECTION_BRANCHES);
    DBCursor branches = collBranches.find(new BasicDBObject(), new BasicDBObject(MongoDBConstants.CID, 1));
    VHistory history = _db.getHistory();
    IdSet alreadyCheckedCommits = new IdHashSet();
    for (DBObject o : branches) {
        long cid = (Long) o.get(MongoDBConstants.CID);
        while (cid != 0) {
            if (alreadyCheckedCommits.contains(cid)) {
                break;
            }
            alreadyCheckedCommits.add(cid);
            danglingCommits.remove(cid);
            cid = history.getParent(cid);
        }
    }

    //all remaining commits must be dangling
    return danglingCommits.toArray();
}

From source file:de.fhg.igd.mongomvcc.impl.MongoDBVMaintenance.java

License:Open Source License

private long[] doFindUnreferencedDocuments(String collection, long expiry, TimeUnit unit) {
    long maxTime = getMaxTime(expiry, unit);

    //fetch the OIDs of all documents older than the expiry time
    DBCollection collDocs = _db.getDB().getCollection(collection);
    DBCursor docs = collDocs.find(
            new BasicDBObject(MongoDBConstants.TIMESTAMP,
                    new BasicDBObject("$not", new BasicDBObject("$gte", maxTime))), //also include docs without a timestamp
            new BasicDBObject(MongoDBConstants.ID, 1));
    IdSet oids = new IdHashSet(docs.count());
    for (DBObject o : docs) {
        oids.add((Long) o.get(MongoDBConstants.ID));
    }/*from   www.ja  v  a  2s  .c o m*/

    //iterate through all commits and eliminate referenced documents
    DBCollection collCommits = _db.getDB().getCollection(MongoDBConstants.COLLECTION_COMMITS);
    for (DBObject o : collCommits.find()) {
        Commit c = Tree.deserializeCommit(o);
        Map<String, IdMap> allObjs = c.getObjects();
        IdMap objs = allObjs.get(collection);
        if (objs != null) {
            //eliminate OIDs referenced by this commit
            IdMapIterator mi = objs.iterator();
            while (mi.hasNext()) {
                mi.advance();
                oids.remove(mi.value());
            }
        }
    }

    //the remaining OIDs must be the unreferenced ones
    return oids.toArray();
}