accord-core/src/main/java/accord/coordinate/CoordinateNoOp.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 accord.coordinate;

import java.util.List;

import accord.api.Result;
import accord.local.Node;
import accord.messages.Apply;
import accord.messages.PreAccept.PreAcceptOk;
import accord.primitives.Ballot;
import accord.primitives.Deps;
import accord.primitives.FullRoute;
import accord.primitives.Seekables;
import accord.primitives.Timestamp;
import accord.primitives.Txn;
import accord.primitives.TxnId;
import accord.primitives.Writes;
import accord.topology.Topologies;
import accord.utils.Invariants;
import accord.utils.async.AsyncResult;
import accord.utils.async.AsyncResults;

import static accord.coordinate.Propose.Invalidate.proposeAndCommitInvalidate;
import static accord.primitives.Txn.Kind.NoOp;

/**
 * Perform initial rounds of PreAccept and Accept until we have reached agreement about when we should execute.
 * If we are preempted by a recovery coordinator, we abort and let them complete (and notify us about the execution result)
 *
 * TODO (desired, testing): dedicated burn test to validate outcomes
 */
public class CoordinateNoOp extends CoordinatePreAccept<Timestamp>
{
    private CoordinateNoOp(Node node, TxnId txnId, Txn txn, FullRoute<?> route)
    {
        super(node, txnId, txn, route);
    }

    public static AsyncResult<Timestamp> coordinate(Node node, Seekables<?, ?> keysOrRanges)
    {
        TxnId txnId = node.nextTxnId(NoOp, keysOrRanges.domain());
        return coordinate(node, txnId, keysOrRanges);
    }

    public static AsyncResult<Timestamp> coordinate(Node node, TxnId txnId, Seekables<?, ?> keysOrRanges)
    {
        Invariants.checkArgument(txnId.kind() == NoOp);
        FullRoute<?> route = node.computeRoute(txnId, keysOrRanges);
        TopologyMismatch mismatch = TopologyMismatch.checkForMismatch(node.topology().globalForEpoch(txnId.epoch()), txnId, route.homeKey(), keysOrRanges);
        if (mismatch != null)
            return AsyncResults.failure(mismatch);
        CoordinateNoOp coordinate = new CoordinateNoOp(node, txnId, node.agent().emptyTxn(NoOp, keysOrRanges), route);
        coordinate.start();
        return coordinate;
    }

    @Override
    void onPreAccepted(Topologies topologies, Timestamp executeAt, List<PreAcceptOk> successes)
    {
        if (executeAt.isRejected())
        {
            proposeAndCommitInvalidate(node, Ballot.ZERO, txnId, route.homeKey(), route, executeAt, this);
        }
        else
        {
            Deps preacceptDeps = Deps.merge(successes, ok -> ok.deps);
            new Propose<Timestamp>(node, topologies, Ballot.ZERO, txnId, txn, route, executeAt, preacceptDeps, this)
            {
                @Override
                void onAccepted()
                {
                    Writes writes = txn.execute(txnId, txnId, null);
                    Result result = txn.result(txnId, executeAt, null);
                    Deps acceptDeps = Deps.merge(this.acceptOks, ok -> ok.deps);
                    Apply.sendMaximal(node, txnId, route, txn, executeAt, acceptDeps, writes, result);
                    accept(executeAt, null);
                }
            }.start();
        }
    }
}