nl.topicus.jdbc.shaded.com.google.cloud.spanner.TransactionRunner Maven / Gradle / Ivy
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/*
* Copyright 2017 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in nl.topicus.jdbc.shaded.com.liance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.nl.topicus.jdbc.shaded.org.licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package nl.topicus.jdbc.shaded.com.google.cloud.spanner;
import nl.topicus.jdbc.shaded.com.google.cloud.Timestamp;
import nl.topicus.jdbc.shaded.javax.annotation.Nullable;
/**
* An interface for executing a body of work in the context of a read-write transaction, with
* retries for transaction aborts. See {@link TransactionContext} for a description of transaction
* semantics. {@code TransactionRunner} instances are obtained by calling {@link
* Session#readWriteTransaction()}.
*
* A {@code TransactionRunner} instance can only be used for a single invocation of {@link
* #run(TransactionCallable)}.
*/
public interface TransactionRunner {
/** A unit of work to be performed in the context of a transaction. */
interface TransactionCallable {
/**
* Invoked by the library framework to perform a single attempt of a transaction. This method
* may be called more than once if previous transaction attempts aborted. Each invocation can
* perform zero or more reads or queries and can buffer mutations to be applied to the database
* when the transaction nl.topicus.jdbc.shaded.com.its.
*
* The framework will attempt to nl.topicus.jdbc.shaded.com.it the transaction when this method returns normally. If
* nl.topicus.jdbc.shaded.com.it is successful, the return value from this method will be returned from {@link
* TransactionRunner#run(TransactionCallable)}; on failure, the transaction may be retried by
* the framework by calling the method again.
*
*
If this method raises an exception, one of two things can happen. If some operation in the
* transaction has previously detected that the transaction has been aborted, the framework may
* retry the transaction. Otherwise, the framework will roll back the transaction, releasing any
* locks held, and yield the exception to the caller as a {@link SpannerException} of type
* {@link ErrorCode#UNKNOWN} with the exception as the cause.
*/
@Nullable
T run(TransactionContext transaction) throws Exception;
}
/**
* Executes a read-write transaction, with retries as necessary. The work to perform in each
* transaction attempt is defined by {@code callable}, which may return an object as the result of
* the work. {@code callable} will be retried if a transaction attempt aborts; implementations
* must be prepared to be called more than once. Any writes buffered by {@code callable} will only
* be applied if the transaction nl.topicus.jdbc.shaded.com.its successfully. Similarly, the value produced by {@code
* callable} will only be returned by this method if the transaction nl.topicus.jdbc.shaded.com.its successfully.
*
*
{@code callable} is allowed to raise an unchecked exception. Typically this prevents further
* attempts to execute {@code callable}, and the exception will propagate from this method call.
* However, if a read or query in {@code callable} detected that the transaction aborted, {@code
* callable} will be retried even if it raised an exception.
*/
@Nullable
T run(TransactionCallable callable);
/**
* Returns the timestamp at which the transaction nl.topicus.jdbc.shaded.com.itted. This method may only be called once
* {@link #run(TransactionCallable)} has returned normally.
*/
Timestamp getCommitTimestamp();
}