Example usage for com.mongodb.client MongoClient startSession

Introduction

In this page you can find the example usage for com.mongodb.client MongoClient startSession.

Prototype

ClientSession startSession(ClientSessionOptions options);

Source Link

Document

Creates a client session.

Usage

From source file:documentation.CausalConsistencyExamples.java

License:Apache License

/**
 * Run this main method to see the output of this quick example.
 *
 * @param args takes an optional single argument for the connection string
 *///w  w  w.  ja  v  a2s .c o m
public static void main(final String[] args) {
    setupDatabase();
    MongoClient client = MongoClients.create();

    // Start Causal Consistency Example 1
    // Example 1: Use a causally consistent session to ensure that the update occurs before the insert.
    ClientSession session1 = client
            .startSession(ClientSessionOptions.builder().causallyConsistent(true).build());
    Date currentDate = new Date();
    MongoCollection<Document> items = client.getDatabase("test").withReadConcern(ReadConcern.MAJORITY)
            .withWriteConcern(WriteConcern.MAJORITY.withWTimeout(1000, TimeUnit.MILLISECONDS))
            .getCollection("test");

    items.updateOne(session1, eq("sku", "111"), set("end", currentDate));

    Document document = new Document("sku", "nuts-111").append("name", "Pecans").append("start", currentDate);
    items.insertOne(session1, document);
    // End Causal Consistency Example 1

    // Start Causal Consistency Example 2
    // Example 2: Advance the cluster time and the operation time to that of the other session to ensure that
    // this client is causally consistent with the other session and read after the two writes.
    ClientSession session2 = client
            .startSession(ClientSessionOptions.builder().causallyConsistent(true).build());
    session2.advanceClusterTime(session1.getClusterTime());
    session2.advanceOperationTime(session1.getOperationTime());

    items = client.getDatabase("test").withReadPreference(ReadPreference.secondary())
            .withReadConcern(ReadConcern.MAJORITY)
            .withWriteConcern(WriteConcern.MAJORITY.withWTimeout(1000, TimeUnit.MILLISECONDS))
            .getCollection("items");

    for (Document item : items.find(session2, eq("end", BsonNull.VALUE))) {
        System.out.println(item);
    }
    // End Causal Consistency Example 2
}

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