/
aggregate.go
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/
aggregate.go
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// Copyright (c) 2014 - The Event Horizon 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 events
import (
"context"
eh "github.com/looplab/eventhorizon"
)
// VersionedAggregate is an interface representing a versioned aggregate created
// from events. It receives commands and generates events that are stored.
//
// The aggregate is created/loaded and saved by the Repository inside the
// Dispatcher. A domain specific aggregate can either implement the full interface,
// or more commonly embed *AggregateBase to take care of the common methods.
type VersionedAggregate interface {
// Provides all the basic aggregate data.
eh.Aggregate
// Provides events to persist and publish from the aggregate.
eh.EventSource
// AggregateVersion returns the version of the aggregate.
AggregateVersion() int
// SetAggregateVersion sets the version of the aggregate. It should only be
// called after an event has been successfully applied, often by EH.
SetAggregateVersion(int)
// ApplyEvent applies an event on the aggregate by setting its values.
// If there are no errors the version should be incremented by calling
// IncrementVersion.
ApplyEvent(context.Context, eh.Event) error
}