com.hedera.node.app.service.file.ReadableUpgradeFileStore Maven / Gradle / Ivy
/*
* Copyright (C) 2023-2024 Hedera Hashgraph, 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 com.hedera.node.app.service.file;
import com.hedera.hapi.node.base.FileID;
import com.hedera.hapi.node.state.file.File;
import com.hedera.pbj.runtime.io.buffer.Bytes;
import com.swirlds.state.spi.ReadableQueueState;
import com.swirlds.state.spi.Schema;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.io.IOException;
/**
* Provides read-only methods for interacting with the underlying data storage mechanisms for
* working with Upgrade Files.
*
* This class is not exported from the module. It is an internal implementation detail.
*/
public interface ReadableUpgradeFileStore {
/**
* Gets the "state key" that uniquely identifies this {@link ReadableQueueState} within the {@link
* Schema} which are scoped to the service implementation. The key is therefore not globally
* unique, only unique within the service implementation itself.
*
*
The call is idempotent, always returning the same value. It must never return null.
*
* @return The state key. This will never be null, and will always be the same value for an
* instance of {@link ReadableQueueState}.
*/
@NonNull
String getStateKey();
/**
* Retrieves but does not remove the element at the head of the queue, or returns null if the queue is empty.
*
* @return The element at the head of the queue, or null if the queue is empty
*/
@Nullable
File peek(FileID fileID);
/**
* Gets the full contents of the file from state.
* @return The full contents of the file
* @throws IOException if the file cannot be read
*/
Bytes getFull(FileID fileID) throws IOException;
}