db simple

xodus

import java.util.List;

import jetbrains.exodus.entitystore.Entity;
import jetbrains.exodus.entitystore.EntityIterable;
import jetbrains.exodus.entitystore.PersistentEntityStore;
import jetbrains.exodus.entitystore.PersistentEntityStores;
import jetbrains.exodus.entitystore.StoreTransaction;

//https://github.com/JetBrains/xodus/wiki/Entity-Stores#search-queries
//https://mvnrepository.com/artifact/org.jetbrains.xodus/xodus-entity-store/1.0.4
//https://mvnrepository.com/artifact/org.jetbrains.xodus
public class LMDBTest {


	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		String path = "data/.myAppData";
		
		
		final PersistentEntityStore store = PersistentEntityStores.newInstance(path);
		System.out.println(store.getLocation());
		
		store.clear();//clear the db
		store.getBlobVault().clear();
		
		StoreTransaction txn = store.beginTransaction(); 
			

		//final StoreTransaction txn = store.beginReadonlyTransaction();
		try {
			do {
				// do something

				
				Entity user = txn.newEntity("User");

				user.setProperty("name", "Xodus");
				user.setProperty("version", "1.0.4");
				user.setProperty("license", "Apache License 2.0 and OLDAP License");
				
				 user = txn.newEntity("q");
				user.setProperty("name", "Xodus");
				user.setProperty("version", "1.0.4");
				user.setProperty("license", "Apache License 2.0 and OLDAP License");
				

				
				 user = txn.newEntity("q");
				user.setProperty("name", "Xodus");
				user.setProperty("version", "1.0.4");
				user.setProperty("license", "Apache License 2.0 and OLDAP License");
				
				EntityIterable allUsers = txn.getAll("q");
				for (Entity u: allUsers) {
					System.out.println(u.getProperty("name"));
				}

				long size = txn.getAll("q").size();
				System.out.println("Size of entity is "+size);

				//MoreObjects.firstNonNull(u.getProperty("name")
				
				final EntityIterable candidates = txn.find("User", "name","Xodus").intersect(txn.find("User", "version", "1.0.4"));
				
				for (Entity candidate: candidates) {
					
					System.out.println("license is "+candidate.getProperty("license"));
					System.out.println("version is "+candidate.getProperty("version"));
					System.out.println("property is "+candidate.getProperty("comment"));
					
				}
			
				// if txn has already been aborted in user codeore.
				if (txn != store.getCurrentTransaction()) {
					txn = null;
					break;
				}
			} while (!txn.flush());
		} finally {
			// if txn has not already been aborted in execute()
			if (txn != null) {
				
				txn.abort();
				txn=null;
				System.out.println("Txn is nulled");
			}
		}
		store.getBlobVault().close();
		store.close();//closing the entity store
	}

	

}