com.swirlds.virtualmap.internal.VirtualStateAccessor Maven / Gradle / Ivy

Go to download
/*
 * Copyright (C) 2021-2024 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.swirlds.virtualmap.internal;

/**
 * Provides access to virtual merkle state, such as the name of the instance, the first
 * and last leaf paths, and the size. It also provides access to some statistics
 * machinery (although, when statistics is refactored, this should change).
 */
public interface VirtualStateAccessor {
    /**
     * Gets the label of the instance.
     *
     * @return The label. This will never be null.
     */
    String getLabel();

    /**
     * Gets the first leaf path. This may be {@link Path#INVALID_PATH} if there are no leaves,
     * but otherwise will be a value greater than zero and less than {@link #getLastLeafPath()}.
     *
     * @return The first leaf path.
     */
    long getFirstLeafPath();

    /**
     * Gets the last leaf path. This may be {@link Path#INVALID_PATH} if there are no leaves,
     * but otherwise will be a value greater than or equal to {@link #getFirstLeafPath()}. It
     * is only equal to {@link #getFirstLeafPath()} when there is a single leaf in the tree.
     *
     * @return The last leaf path.
     */
    long getLastLeafPath();

    /**
     * Sets the first leaf path.
     *
     * @param path
     * 		Sets the first leaf path. The path must be greater than zero, or {@link Path#INVALID_PATH}, and
     * 		strictly less than or equal to {@link #getLastLeafPath()}.
     */
    void setFirstLeafPath(long path);

    /**
     * Sets the last leaf path.
     *
     * @param path
     * 		Sets the last leaf path. The path must be greater than zero, or {@link Path#INVALID_PATH}, and
     * 		strictly greater than or equal to {@link #getFirstLeafPath()}.
     */
    void setLastLeafPath(long path);

    /**
     * Gets the size. This is computed based on the first and last leaf path values.
     *
     * @return The size.
     */
    long size();
}