org.neo4j.bolt.v1.runtime.bookmarking.Bookmark Maven / Gradle / Ivy

/*
 * Copyright (c) 2002-2017 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.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.bolt.v1.runtime.bookmarking;

import java.util.List;
import java.util.Map;

import org.neo4j.kernel.api.exceptions.KernelException;
import org.neo4j.kernel.api.exceptions.Status;

import static java.lang.String.format;

public class Bookmark
{
    private static final String BOOKMARK_KEY = "bookmark";
    private static final String BOOKMARKS_KEY = "bookmarks";
    private static final String BOOKMARK_TX_PREFIX = "neo4j:bookmark:v1:tx";

    private final long txId;

    public Bookmark( long txId )
    {
        this.txId = txId;
    }

    @Override
    public String toString()
    {
        return format( BOOKMARK_TX_PREFIX + "%d", txId );
    }

    public static Bookmark fromParamsOrNull( Map params ) throws BookmarkFormatException
    {
        // try to parse multiple bookmarks, if available
        Bookmark bookmark = parseMultipleBookmarks( params );
        if ( bookmark == null )
        {
            // fallback to parsing single bookmark, if available, for backwards compatibility reasons
            // some older drivers can only send a single bookmark
            return parseSingleBookmark( params );
        }
        return bookmark;
    }

    public long txId()
    {
        return txId;
    }

    private static Bookmark parseMultipleBookmarks( Map params ) throws BookmarkFormatException
    {
        Object bookmarksObject = params.get( BOOKMARKS_KEY );

        if ( bookmarksObject == null )
        {
            return null;
        }
        else if ( bookmarksObject instanceof List )
        {
            List bookmarks = (List) bookmarksObject;

            long maxTxId = -1;
            for ( Object bookmark : bookmarks )
            {
                if ( bookmark != null )
                {
                    long txId = txIdFrom( bookmark.toString() );
                    if ( txId > maxTxId )
                    {
                        maxTxId = txId;
                    }
                }
            }
            return maxTxId == -1 ? null : new Bookmark( maxTxId );
        }
        else
        {
            throw new BookmarkFormatException( bookmarksObject );
        }
    }

    private static Bookmark parseSingleBookmark( Map params ) throws BookmarkFormatException
    {
        Object bookmarkObject = params.get( BOOKMARK_KEY );
        if ( bookmarkObject == null )
        {
            return null;
        }

        String bookmarkString = bookmarkObject.toString();
        return new Bookmark( txIdFrom( bookmarkString ) );
    }

    private static long txIdFrom( String bookmarkString ) throws BookmarkFormatException
    {
        if ( !bookmarkString.startsWith( BOOKMARK_TX_PREFIX ) )
        {
            throw new BookmarkFormatException( bookmarkString );
        }

        try
        {
            return Long.parseLong( bookmarkString.substring( BOOKMARK_TX_PREFIX.length() ) );
        }
        catch ( NumberFormatException e )
        {
            throw new BookmarkFormatException( bookmarkString, e );
        }
    }

    static class BookmarkFormatException extends KernelException
    {
        BookmarkFormatException( String bookmarkString, NumberFormatException e )
        {
            super( Status.Transaction.InvalidBookmark, e, "Supplied bookmark [%s] does not conform to pattern %s; " +
                    "unable to parse transaction id", bookmarkString, BOOKMARK_TX_PREFIX );
        }

        BookmarkFormatException( Object bookmarkObject )
        {
            super( Status.Transaction.InvalidBookmark, "Supplied bookmark [%s] does not conform to pattern %s",
                    bookmarkObject, BOOKMARK_TX_PREFIX );
        }
    }
}