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Cypher Shell

There is a newer version: 2025.02.0

/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [https://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.neo4j.shell;

import static java.lang.System.getProperty;

import java.io.IOException;
import java.nio.file.Path;
import java.util.Collections;
import java.util.List;

/**
 * An object which keeps a record of past commands
 */
public interface Historian {
    Historian empty = new EmptyHistory();

    /**
     * @return a list of all past commands in the history, in order of execution (first command sorted first).
     */
    List getHistory();

    /**
     * Flush history to disk
     */
    void flushHistory() throws IOException;

    void clear() throws IOException;

    static Path defaultHistoryFile() {
        // Storing in same directory as driver uses
        return Path.of(getProperty("user.home"), ".neo4j", ".cypher_shell_history");
    }

    class EmptyHistory implements Historian {
        @Override
        public List getHistory() {
            return Collections.emptyList();
        }

        @Override
        public void flushHistory() throws IOException {}

        @Override
        public void clear() throws IOException {}
    }
}