Develop Reference

Does spring-data-mongodb supports Atlas search? need an example of it

I am trying to find how to use mongo Atlas search indexes, from java application, which is using spring-data-mongodb to query the data, can anyone share an example for it
what i found was as code as below, but that is used for MongoDB Text search, though it is working, but not sure whether it is using Atlas search defined index.
TextQuery textQuery = TextQuery.queryText(new TextCriteria().matchingAny(text)).sortByScore();
textQuery.fields().include("cast").include("title").include("id");
List<Movies> movies = mongoOperations
.find(textQuery, Movies.class);
I want smaple java code using spring-data-mongodb for below query:
[
{
$search: {
index: 'cast-fullplot',
text: {
query: 'sandeep',
path: {
'wildcard': '*'
}
}
}
}
]
It will be helpful if anyone can explain how MongoDB Text Search is different from Mongo Atlas Search and correct way of using Atalas Search with the help of java spring-data-mongodb.
How to code below with spring-data-mongodb:
Arrays.asList(new Document("$search",
new Document("index", "cast-fullplot")
.append("text",
new Document("query", "sandeep")
.append("path",
new Document("wildcard", "*")))),
new Document())

Yes, spring-data-mongo supports the aggregation pipeline, which you'll use to execute your query.
You need to define a document list, with the steps defined in your query, in the correct order. Atlas Search must be the first step in the pipeline, as it stands. You can translate your query to the aggregation pipeline using the Mongo Atlas interface, they have an option to export the pipeline array in the language of your choosing. Then, you just need to execute the query and map the list of responses to your entity class.
You can see an example below:
public class SearchRepositoryImpl implements SearchRepositoryCustom {
private final MongoClient mongoClient;
public SearchRepositoryImpl(MongoClient mongoClient) {
this.mongoClient = mongoClient;
}
#Override
public List<SearchEntity> searchByFilter(String text) {
// You can add codec configuration in your database object. This might be needed to map
// your object to the mongodb data
MongoDatabase database = mongoClient.getDatabase("aggregation");
MongoCollection<Document> collection = database.getCollection("restaurants");
List<Document> pipeline = List.of(new Document("$search", new Document("index", "default2")
.append("text", new Document("query", "Many people").append("path", new Document("wildcard", "*")))));
List<SearchEntity> searchEntityList = new ArrayList<>();
collection.aggregate(pipeline, SearchEntity.class).forEach(searchEntityList::add);
return searchEntityList;
}
}

How to only get from MongoDB documents that match a specific filter using Java

My MongoDB Documents are like this:
"_id":"C\Users...\1.html"{
"data": Object[
gambia:1
estonia:1
...etc
]
}
I don't know if I wrote correctly the structure, so here you have a picture:
My problem is that I want to get from DB all Documents that match a specific word given. For example if the user enters "car" I need all the documents that in its data have the word car. But I couldn't find how to do it.
What I tried? I tried to get the first document that matches the word "gambia" which I know it exists in the first Document:
MongoClient mongoClient = MongoClients.create();
MongoDatabase database = mongoClient.getDatabase("motor");
MongoCollection<Document> collection = database.getCollection("dictionary");
String word = "gambia";
Document myDoc = collection.find(Filters.eq("data", word)).first();
System.out.println(myDoc);
But I'm getting a null pointer exception.

You can achieve this using the mongodb function $exists.
This function tells you if a determinated field, is in your collection.
For example:
MongoCollection<Document> collection = database.getCollection("dictionary");
String word = "gambia";
DBObject query = new BasicDBObject("data." + word, new BasicDBObject(
"$exists", true));
Document myDoc = collection.find(query);
System.out.println(myDoc);

Tailable Cursor example in Java using 3.0 driver?

Can someone please provide a complete tailable cursor example in Java? I am using the 3.0 driver and all examples appear to be 2.x. I have only mongo-java-driver-3.0.0.jar in my classpath. I want to get all documents as they are inserted in my capped collection.
//this does not work...
MongoCollection<BasicDBObject> col = database.getCollection(colName, BasicDBObject.class);
DBCursor cur = col.find().sort(new BasicDBObject("$natural", 1))
.addOption(Bytes.QUERYOPTION_TAILABLE)
.addOption(Bytes.QUERYOPTION_AWAITDATA);
// And this does not work...
BasicDBObjectBuilder builder = BasicDBObjectBuilder.start();
builder.add("messageType","STATUS_REQUEST");
DBObject searchQuery = builder.get();
DBObject sortBy = BasicDBObjectBuilder.start("$natural", 1).get();
BasicDBObjectBuilder builderForFields = BasicDBObjectBuilder.start();
DBObject fields = builderForFields.get();
DBCursor cursor = new DBCursor(col, searchQuery, fields, ReadPreference.primary() );
cursor.sort(sortBy);
cursor.addOption(Bytes.QUERYOPTION_AWAITDATA);
cursor.addOption(Bytes.QUERYOPTION_TAILABLE);
//this does work but only returns the messageNumber field. I need the doc.
MongoCursor<Long> c = database.getCollection(colName).distinct("messageNumber", Long.class).iterator();
I see that the MongoCursor interface was added in 3.0. What is that for and does it replace DBCursor?
Thanks a lot

A bit late to the party, but in case you still need help:
find(query).projection(fields).cursorType(CursorType.TailableAwait).iterator();
That code applies to the MongoCollection class.
CursorType is an enum and it has the following values:
Tailable
TailableAwait
Corresponding to the old DBCursor addOption Bytes types:
Bytes.QUERYOPTION_TAILABLE
Bytes.QUERYOPTION_AWAITDATA
I hope that helps.

This is what you might be looking for - EVENT Streaming in MongoDB 3.0.* using new api i.e. 3.0.2
Document query = new Document(); \\here use { indexedField: { $gt: <lastvalue> } index is not used(except for auto deleting documents) but created in capped collection
Document projection = new Document();
MongoCursor<Document> cursor= mongocollection.find(query).projection(projection).cursorType(CursorType.TailableAwait).iterator(); //add .noCursorTimeout(true) here to avoid timeout if you are working on big data
while (cursor.hasNext()){
Document doc = cursor.next();
//do what you want with doc
}
This way mongo cursor will check for new entries in capped collection

In your last line, replace .distinct("messageNumber", Long.class) with .find().
distinct(String fieldName, Class<TResult> resultClass) returns only the unique values of the one field you request.
find() returns all documents of the collection with all of their fields.

insert text data values eg(date time PH value) in Mongodb every 3 hours automatically using java

I have a mongodb database, I need to insert text data values eg(date time PH value) every 3 hours automatically using java.
Need help
I have made a mongodb database called project and collection called Water Monetering system
also here is the basic layout of java- mongodb integration
import com.mongodb.MongoClient;
import com.mongodb.MongoException;
import com.mongodb.WriteConcern;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;
import com.mongodb.DBCursor;
import com.mongodb.ServerAddress;
import java.util.Arrays;
public class MongoDBJDBC{
public static void main( String args[] ){
try{
// To connect to mongodb server
MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
// Now connect to your databases
DB db = mongoClient.getDB( "project" );
System.out.println("Connect to database successfully");
DBCollection coll = db.getCollection("WaterMoneteringSystem");
System.out.println("Collection WaterMoneteringSystem selected successfully");
BasicDBObject doc = new BasicDBObject("title", "Watermoneteringsystem").
append("Date", "date").
append("time", "time").
append("value", "ph").
coll.insert(doc);
System.out.println("Document inserted successfully");
}catch(Exception e){
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
}
}
}
I am not getting how data(date time PH) in text box can be implemented
Thank you

Instead of:
BasicDBObject doc = new BasicDBObject("title", "Watermoneteringsystem").
append("Date", "date").
append("time", "time").
append("value", "ph");
You need something like:
BasicDBObject doc = new BasicDBObject("title", "Watermoneteringsystem").
append("Date", new Date()).
append("value", "ph");
The new Date() call will set today's date and time in there (you don't need separate fields for date and time).
But the "ph" bit needs to come from some other place - where are you getting the ph values from? Is it going to be an argument (i.e. in args[])? Is it coming from a file, or external system?
Assuming it's something you can pass in to the method, you can do something like:
String phValue = args[0];
BasicDBObject doc = new BasicDBObject("title", "Watermoneteringsystem").
append("Date", new Date()).
append("value", phValue);
I'd suggest renaming the field to something like "ph" or "phValue" as well, since "value" is not a helpful field name.
Take a look at the MongoDB and Java documentation, there are more examples there in how to use MongoDB from Java.

not able to insert documents into collection using mongodb java driver

I'm using mongo mongo java driver version 2.11.2. I want to insert some few documents into my dbin mongodb and when I try to do it from command line it all works fine. But when I use mongo java driver, it is not working. I'm using BasicDBObject to populate the document. But collection.insert(BasicDBObject).getN() gives me 0 always. Nothing is getting inserted into the collection. Am I missing something here?
Adding the code:
mongo = new MongoClient("localhost", 27017);
DB db = mongo.getDB("db");
DBCollection collection = db.getCollection("collection");
BasicDBObject o = new BasicDBObject();
o.put("key1", "value1");
o.put("key2", "value2");
collection.insert(o);
No update is made in DB after this.

The 'n' value from the getlasterror of an insert is always zero. (The 'n' value is what the WriteResult.getN() returns.)
See this MongoDB Jira ticket: https://jira.mongodb.org/browse/SERVER-4381. Which has been closed in preference to a new insert, update, remove mechanism: https://jira.mongodb.org/browse/SERVER-9038
Long story short. You are not mad or missing anything. It is a "feature" of MongoDB that will hopefully finally be fixed with the 2.6 release.
Rob.
Edit:
I modified your example slightly to print the saved document. Can you try running this version in your environment?
import java.net.UnknownHostException;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.WriteConcern;
public class StackOverFlow {
public static void main(String[] args) throws UnknownHostException {
MongoClient mongo = new MongoClient("localhost:27017");
DB db = mongo.getDB("db");
DBCollection collection = db.getCollection("collection");
BasicDBObject o = new BasicDBObject();
o.put("key1", "value1");
o.put("key2", "value2");
collection.insert(WriteConcern.SAFE, o);
for (DBObject doc : collection.find()) {
System.out.println(doc);
}
}
}
On my machine it outputs:
{ "_id" : { "$oid" : "5235f98495302901eb70e7a4"} , "key1" : "value1" , "key2" : "value2"}