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Conflict-free replicated data type implementation for DataKernel Framework.
/*
* Copyright (C) 2015-2019 SoftIndex LLC.
*
* 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 io.datakernel.crdt;
import io.datakernel.datastream.StreamConsumer;
import io.datakernel.datastream.StreamSupplier;
import io.datakernel.promise.Promise;
/**
* Interface for various CRDT client implementations.
* CRDT storage can be seen as SortedMap where put operation is same as merge with CRDT union as combiner.
*
* @param type of crdt keys
* @param type of crdt states
*/
public interface CrdtStorage, S> {
/**
* Returns a consumer of key-state pairs to be added to the CRDT storage.
*
* @return stage of stream consumer of key-state pairs.
*/
Promise>> upload();
/**
* Returns a producer if all key-state pairs in the CRDT storage that were put AFTER given timestamp was received.
* Pairs are sorted by key.
*
* @return stage of stream producer of key-state pairs
*/
Promise>> download(long timestamp);
/**
* Same as above, but downloads all possible key-state pairs.
*
* @return stage of stream producer of key-state pairs
*/
default Promise>> download() {
return download(0);
}
/**
* Returns a consumer of keys to be removed from the CRDT storage.
* This operation is not persistent and not guaranteed.
*
* @return stage of stream consumer of keys
*/
Promise> remove();
/**
* Marker that this client is functional (server is up, there are enough nodes in cluster etc.)
*
* @return stage that succeeds if this client is up
*/
Promise ping();
}