io.zeebe.logstreams.spi.ReadableSnapshot 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.io.InputStream;

import io.zeebe.logstreams.snapshot.InvalidSnapshotException;

/**
 * Represents a snapshot of the log.
 */
public interface ReadableSnapshot
{
    /**
     * The log position at which the snapshot was taken.
     */
    long getPosition();

    /**
     * Input stream to read the snapshot data.
     *
     * @return the snapshot data as input stream
     */
    InputStream getData();

    /**
     * Consumers of this API must call this method after having read the input
     * stream. The method validates that the bytes read are valid and closes any
     * underlying resources.
     *
     * @throws InvalidSnapshotException
     *             if not valid
     */
    void validateAndClose() throws InvalidSnapshotException;

    /**
     * Deletes the snapshot and related data.
     */
    void delete();

    /**
     * Reads the snapshot data and recover the given snapshot object. At the end,
     * it validates that the bytes read are valid and closes any underlying resources.
     *
     * @param snapshotSupport
     *            the snapshot object
     * @throws Exception
     *             if fails to recover the snapshot object
     * @throws InvalidSnapshotException
     *             if the snapshot is not valid
     */
    default void recoverFromSnapshot(SnapshotSupport snapshotSupport) throws Exception
    {
        snapshotSupport.reset();
        snapshotSupport.recoverFromSnapshot(getData());
        validateAndClose();
    }

    /**
     * @return the initial snapshot name
     */
    String getName();

    /**
     * @return length in bytes of the snapshot contents
     */
    long getLength();

    /**
     * @return the checksum of the snapshot contents
     */
    byte[] getChecksum();
}