io.zeebe.logstreams.spi.SnapshotStorage Maven / Gradle / Ivy

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/*
 * Copyright © 2017 camunda services GmbH ([email protected])
 *
 * 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.zeebe.logstreams.spi;

import java.util.List;

/** Storage for log snapshots. */
public interface SnapshotStorage {

  /**
   * Returns the last snapshot for the given name.
   *
   * @param name the name of the snapshot
   * @return the snapshot or null if none exists
   * @throws Exception if fails to open the snapshot
   */
  ReadableSnapshot getLastSnapshot(String name) throws Exception;

  /**
   * Returns a writer to create a new snapshot.
   *
   * @param name the name of the snapshot
   * @param logPosition the log position at which the snapshot is taken
   * @return the writer to create the snapshot
   * @throws Exception if fails to create the snapshot
   */
  SnapshotWriter createSnapshot(String name, long logPosition) throws Exception;

  /**
   * Returns a list of available snapshots; for each snapshot item, it returns the latest file.
   *
   * @return all available snapshots
   */
  List listSnapshots();

  /** Returns whether or not there already exists a snapshot for the given name + position. */
  boolean snapshotExists(String name, long logPosition);
}