com.google.cloud.spanner

Interface AsyncTransactionManager.AsyncTransactionFunction<I,O>

Enclosing interface:

AsyncTransactionManager

public static interface AsyncTransactionManager.AsyncTransactionFunction<I,O>

Each step in a transaction chain is defined by an AsyncTransactionManager.AsyncTransactionFunction. It receives a TransactionContext and the output value of the previous transaction step as its input parameters. The method should return an ApiFuture that will return the result of this step.

Method Summary

Modifier and Type	Method and Description
com.google.api.core.ApiFuture<O>	apply(TransactionContext txn, I input) This method is called when this transaction step is executed.

Method Detail

apply

com.google.api.core.ApiFuture<O> apply(TransactionContext txn,
                                       I input)
                                throws Exception

This method is called when this transaction step is executed. The input value is the result of the previous step, and this method will only be called if the previous step executed successfully.

Parameters:

txn - the TransactionContext that can be used to execute statements.

input - the result of the previous transaction step.

Returns:

an ApiFuture that will return the result of this step, and that will be the input of the next transaction step. This method should never return null. Instead, if the method does not have a return value, the method should return ApiFutures#immediateFuture(null).

Throws:

Exception