Package org.hsqldb.index

Source Code of org.hsqldb.index.NodeAVLMemoryPointer

/* Copyright (c) 2001-2009, 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
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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package org.hsqldb.index;

import org.hsqldb.RowAVLDiskData;
import org.hsqldb.RowAVLDisk;
import org.hsqldb.Row;
import org.hsqldb.persist.PersistentStore;

// 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 derived from Hypersonic SQL code and enhanced in HSQLDB. <p>
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 1.9.0
* @since 1.7.1
*/
public class NodeAVLMemoryPointer extends NodeAVLBaseMemory {

    public int      iData = NO_POS;
    private NodeAVL nPrimary;    // node of key / primary index for this row

    public NodeAVLMemoryPointer(RowAVLDisk r) {

        iData    = r.getPos();
        nPrimary = r.nPrimaryNode == null ? this
                                          : r.nPrimaryNode;
    }

    public void delete() {
        super.delete();
    }

    public int getPos() {
        return iData;
    }

    Row getRow(PersistentStore store) {

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

        RowAVLDiskData row = (RowAVLDiskData) store.get(iData, false);

        row.nPrimaryNode = nPrimary;

        return row;
    }
}
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