com.sleepycat.collections.MyRangeCursor Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of je Show documentation

Berkeley DB Java Edition is a open source, transactional storage solution for Java applications. The Direct Persistence Layer (DPL) API is faster and easier to develop, deploy, and manage than serialized object files or ORM-based Java persistence solutions. The Collections API enhances the standard java.util.collections classes allowing them to be persisted to a local file system and accessed concurrently while protected by ACID transactions. Data is stored by serializing objects and managing class and instance data separately so as not to waste space. Berkeley DB Java Edition is the reliable drop-in solution for complex, fast, and scalable storage. Source for this release is in 'je-4.0.92-sources.jar', the Javadoc is located at 'http://download.oracle.com/berkeley-db/docs/je/4.0.92/'.

There is a newer version: 5.0.73

Show newest version

/*-
 * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This file was distributed by Oracle as part of a version of Oracle Berkeley
 * DB Java Edition made available at:
 *
 * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
 *
 * Please see the LICENSE file included in the top-level directory of the
 * appropriate version of Oracle Berkeley DB Java Edition for a copy of the
 * license and additional information.
 */

package com.sleepycat.collections;

import com.sleepycat.compat.DbCompat;
import com.sleepycat.je.Cursor;
import com.sleepycat.je.CursorConfig;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.util.keyrange.KeyRange;
import com.sleepycat.util.keyrange.RangeCursor;

class MyRangeCursor extends RangeCursor {

    private DataView view;
    private boolean isRecnoOrQueue;
    private boolean writeCursor;

    MyRangeCursor(KeyRange range,
                  CursorConfig config,
                  DataView view,
                  boolean writeAllowed)
        throws DatabaseException {

        super(range, view.dupsRange, view.dupsOrdered,
              openCursor(view, config, writeAllowed));
        this.view = view;
        isRecnoOrQueue = view.recNumAllowed && !view.btreeRecNumDb;
        writeCursor = isWriteCursor(config, writeAllowed);
    }

    /**
     * Returns true if a write cursor is requested by the user via the cursor
     * config, or if this is a writable cursor and the user has not specified a
     * cursor config.  For CDB, a special cursor must be created for writing.
     * See CurrentTransaction.openCursor.
     */
    private static boolean isWriteCursor(CursorConfig config,
                                         boolean writeAllowed) {
        return DbCompat.getWriteCursor(config) ||
               (config == CursorConfig.DEFAULT && writeAllowed);
    }

    private static Cursor openCursor(DataView view,
                                     CursorConfig config,
                                     boolean writeAllowed)
        throws DatabaseException {

        return view.currentTxn.openCursor
            (view.db, config, isWriteCursor(config, writeAllowed),
             view.useTransaction());
    }

    protected Cursor dupCursor(Cursor cursor, boolean samePosition)
        throws DatabaseException {

        return view.currentTxn.dupCursor(cursor, writeCursor, samePosition);
    }

    protected void closeCursor(Cursor cursor)
        throws DatabaseException {

        view.currentTxn.closeCursor(cursor);
    }

    protected boolean checkRecordNumber() {
        return isRecnoOrQueue;
    }
}