HSQLDB example source code file (PointerNode.java)

This example HSQLDB source code file (PointerNode.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

basememorynode, cachedrow, hsqlexception, hsqlexception, no_pos, no_pos, node, object, object, pointernode, pointernode, row, table

The HSQLDB PointerNode.java source code

/*
 * For work developed by the HSQL Development Group:
 *
 * Copyright (c) 2001-2010, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 *
 * For work originally developed by the Hypersonic SQL Group:
 *
 * Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Hypersonic SQL Group.
 */


package org.hsqldb;

// fredt@users 20020221 - patch 513005 by sqlbob@users (RMP)
// fredt@users 20020920 - path 1.7.1 - refactoring to cut mamory footprint
// fredt@users 20021205 - path 1.7.2 - enhancements
// fredt@users 20021215 - doc 1.7.2 - javadoc comments

/**
 *  Text table node implementation.<p>
 *  Nodes for the AVL tree are all built and kept in memory while the actual
 *  row data is accessed via TextCache from disk.<p>
 *  This differs from MemoryNode by maintaining an integral pointer for the
 *  Row data instead of a Java reference.
 *
 * New class based on Hypersonic SQL code.
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.7.1
 */
class PointerNode extends BaseMemoryNode {

    int           iData = NO_POS;
    private Table tTable;
    private Node  nPrimary;    // node of key / primary index for this row

    PointerNode(CachedRow r, int id) {

        tTable   = r.getTable();
        iData    = r.iPos;
        nPrimary = r.nPrimaryNode == null ? this
                                          : r.nPrimaryNode;
    }

    void delete() {

        super.delete();

        nPrimary = null;
        tTable   = null;
    }

    int getKey() {
        return iData;
    }

    Row getRow() throws HsqlException {

        if (iData == NO_POS) {
            return null;
        }

        CachedRow r = tTable.getRow(iData, nPrimary);

        return r;
    }

    Object[] getData() throws HsqlException {

        if (Trace.DOASSERT) {
            Trace.doAssert(iBalance != -2);
        }

        return getRow().getData();
    }
}