com.coreos.jetcd.Txn Maven / Gradle / Ivy
/**
* Copyright 2017 The jetcd authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.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 com.coreos.jetcd;
import com.coreos.jetcd.kv.TxnResponse;
import com.coreos.jetcd.op.Cmp;
import com.coreos.jetcd.op.Op;
import java.util.concurrent.CompletableFuture;
/**
* Txn is the interface that wraps mini-transactions.
*
* Usage examples
*
* {@code
* txn.If(
* new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE)),
* new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(2))
* ).Then(
* Op.put(KEY2, VALUE2, PutOption.DEFAULT),
* Op.put(KEY3, VALUE3, PutOption.DEFAULT)
* ).Else(
* Op.put(KEY4, VALUE4, PutOption.DEFAULT),
* Op.put(KEY4, VALUE4, PutOption.DEFAULT)
* ).commit();
* }
*
* Txn also supports If, Then, and Else chaining. e.g.
*
{@code
* txn.If(
* new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE))
* ).If(
* new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(VERSION))
* ).Then(
* Op.put(KEY2, VALUE2, PutOption.DEFAULT)
* ).Then(
* Op.put(KEY3, VALUE3, PutOption.DEFAULT)
* ).Else(
* Op.put(KEY4, VALUE4, PutOption.DEFAULT)
* ).Else(
* Op.put(KEY4, VALUE4, PutOption.DEFAULT)
* ).commit();
* }
*/
public interface Txn {
/**
* takes a list of comparison. If all comparisons passed in succeed,
* the operations passed into Then() will be executed. Or the operations
* passed into Else() will be executed.
*/
//CHECKSTYLE:OFF
Txn If(Cmp... cmps);
//CHECKSTYLE:ON
/**
* takes a list of operations. The Ops list will be executed, if the
* comparisons passed in If() succeed.
*/
//CHECKSTYLE:OFF
Txn Then(Op... ops);
//CHECKSTYLE:ON
/**
* takes a list of operations. The Ops list will be executed, if the
* comparisons passed in If() fail.
*/
//CHECKSTYLE:OFF
Txn Else(Op... ops);
//CHECKSTYLE:OFF
/**
* tries to commit the transaction.
*
* @return a TxnResponse wrapped in CompletableFuture
*/
CompletableFuture commit();
}