Any way I can change in runtime mongo document name - mongodb

Question

In the project we need to change collection name suffix everyday based on date.
So one day collection is named:
samples_22032019
and in the next day it is
samples_23032019
Everyday I need to change suffix and recompile spring-boot application because of this. Is there any way I can change this so the collection/table can be calculated dynamically based on current date? Any advice for MongoRepository?

Answer 1

Considering the below is your bean. you can use #Document annotation with spring expression language to resolve suffix at runtime. Like show below,
#Document(collection = "samples_#{T(com.yourpackage.Utility).getDateSuffix()}")
public class Samples {
private String id;
private String name;
}
Now have your date change function in a Utility method which spring can resolve at runtime. SpEL is handy in such scenarios.
package com.yourpackage;
public class Utility {
public static final String getDateSuffix() {
//Add your real logic here, below is for representational purpose only.
return DateTime.now().toDate().toString();;
}
}
HTH!

Answer 2

Make a cron job to run daily and generateNewName for your collection and execute the below code. Here I am getting collection using MongoDatabse than by using MongoNamespace we can rename the collection.
To get old/new collection name you can write a separate method.
#Component
public class RenameCollectionTask {
#Scheduled(cron = "${cron}")
public void renameCollection() {
// creating mongo client object
final MongoClient client = new MongoClient(HOST_NAME, PORT);
// selecting the mongo database
final MongoDatabase database = client.getDatabase("databaseName");
// selecting the mongo collection
final MongoCollection<Document> collection = database.getCollection("oldCollectionName");
// creating namespace
final MongoNamespace newName = new MongoNamespace("databaseName", "newCollectionName");
// renaming the collection
collection.renameCollection(newName);
System.out.println("Collection has been renamed");
// closing the client
client.close();
}
}
To assign the name of the collection you can refer this so that every time restart will not be required.
The renameCollection() method has the following limitations:
1) It cannot move a collection between databases.
2) It is not supported on sharded collections.
3) You cannot rename the views.
Refer this for detail.