Types of API - SyncEntityDb

The blocking - or sync - API is the simplest API for accessing the Genesis database.

Return values

Get operations in this API are nullable. When getting a record, you must check if it is null:

val trade: Trade? = db.get(Trade.byId("TRADE_1"))
if (trade == null) throw RuntimeException("Unable to find trade")

Write operations return either a single return object, or a list of result objects, for the ...All operations, e.g. updateAll. These are never nullable.

val insert: InsertResult<Trade> = db.insert(trade)
val inserts: List<InsertResult<Trade>> = db.insertAll(myTrades)

getRange and getBulk operations a List<X>:

val trades: List<Trade> = db.getBulk(TRADE)

Note that this will load the entire table into memory. This is fine for smaller tables and ranges. However, for large tables and ranges, the stream() function is provided on the database. This will create a Stream that streams the data, rather than loading it all in memory:

val trades: Stream<Trade> = db.stream().getBulk(TRADE)
try {
    // use the stream here
} finally {
    trades.close()
}

While this is more memory-efficient, the database connection will be kept open until the stream is closed. As in the above example, always close the stream. Not closing these streams will lead to your application running out of database connections.