HSQLDB example source code file (DiskNode.java)

This example HSQLDB source code file (DiskNode.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

cachedrow, disknode, disknode, hsqlexception, hsqlexception, intlookup, io, ioexception, no_pos, no_pos, node, node, object, row, size_in_byte

The HSQLDB DiskNode.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;

import java.io.IOException;

import org.hsqldb.lib.IntLookup;
import org.hsqldb.rowio.RowInputInterface;
import org.hsqldb.rowio.RowOutputInterface;

// 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

/**
 *  Cached table Node implementation.<p>
 *  Only integral references to left, right and parent nodes in the AVL tree
 *  are held and used as pointers data.<p>
 *
 *  iId is a reference to the Index object that contains this node.<br>
 *  This fields can be eliminated in the future, by changing the
 *  method signatures to take a Index parameter from Index.java (fredt@users)
 *
 *  New class derived from the Hypersonic code
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version    1.7.2
 * @since Hypersonic SQL
 */
class DiskNode extends Node {

    protected Row    rData;
    private int      iLeft   = NO_POS;
    private int      iRight  = NO_POS;
    private int      iParent = NO_POS;
    private int      iId;    // id of Index object for this Node
    static final int SIZE_IN_BYTE = 4 * 4;

    DiskNode(CachedRow r, RowInputInterface in,
             int id) throws IOException, HsqlException {

        iId      = id;
        rData    = r;
        iBalance = in.readIntData();
        iLeft    = in.readIntData();

        if (iLeft <= 0) {
            iLeft = NO_POS;
        }

        iRight = in.readIntData();

        if (iRight <= 0) {
            iRight = NO_POS;
        }

        iParent = in.readIntData();

        if (iParent <= 0) {
            iParent = NO_POS;
        }

        if (Trace.DOASSERT) {

            // fredt - assert not correct - row can be deleted from one index but
            // not yet deleted from other indexes while the process of finding
            // the node is in progress which may require saving the row
            // to make way for new rows in the cache and loading it back
            // Trace.doAssert(iBalance != -2);
        }
    }

    DiskNode(CachedRow r, int id) {
        iId   = id;
        rData = r;
    }

    void delete() {
        rData    = null;
        iBalance = -2;
    }

    int getKey() {

        if (rData != null) {
            return ((CachedRow) rData).iPos;
        }

        return NO_POS;
    }

    Row getRow() throws HsqlException {

        if (Trace.DOASSERT) {
            Trace.doAssert(rData != null);
        }

        return rData;
    }

    private Node findNode(int pos) throws HsqlException {

        Node ret = null;
        Row  r   = ((CachedRow) rData).getTable().getRow(pos);

        if (r != null) {
            ret = r.getNode(iId);
        }

        return ret;
    }

    boolean isLeft(Node node) throws HsqlException {

        if (node == null) {
            return iLeft == NO_POS;
        }

        return iLeft == ((DiskNode) node).getKey();
    }

    boolean isRight(Node node) throws HsqlException {

        if (node == null) {
            return iRight == NO_POS;
        }

        return iRight == ((DiskNode) node).getKey();
    }

    Node getLeft() throws HsqlException {

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

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

        return findNode(iLeft);
    }

    Node getRight() throws HsqlException {

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

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

        return findNode(iRight);
    }

    Node getParent() throws HsqlException {

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

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

        return findNode(iParent);
    }

    boolean isRoot() {
        return iParent == Node.NO_POS;
    }

    boolean isFromLeft() throws HsqlException {

        if (this.isRoot()) {
            return true;
        }

        if (Trace.DOASSERT) {
            Trace.doAssert(getParent() != null);
        }

        DiskNode parent = (DiskNode) getParent();

        return getKey() == parent.iLeft;
    }

    Object[] getData() throws HsqlException {

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

        return rData.getData();
    }

    void setParent(Node n) throws HsqlException {

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

        ((CachedRow) rData).setChanged();

        iParent = n == null ? NO_POS
                            : n.getKey();
    }

    void setBalance(int b) throws HsqlException {

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

        if (iBalance != b) {
            ((CachedRow) rData).setChanged();

            iBalance = b;
        }
    }

    void setLeft(Node n) throws HsqlException {

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

        ((CachedRow) rData).setChanged();

        iLeft = n == null ? NO_POS
                          : n.getKey();
    }

    void setRight(Node n) throws HsqlException {

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

        ((CachedRow) rData).setChanged();

        iRight = n == null ? NO_POS
                           : n.getKey();
    }

    boolean equals(Node n) {

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

            if (n != this) {
                boolean test = (getKey() == NO_POS) || (n == null)
                               || (n.getKey() != getKey());

                if (test == false) {
                    test = iParent == ((DiskNode) n).iParent
                           && iLeft == ((DiskNode) n).iLeft
                           && iRight == ((DiskNode) n).iRight;

                    if (test == false) {
                        int aA = ((CachedRow) getRow()).iLastAccess;
                        int bA = ((CachedRow) n.getRow()).iLastAccess;

                        Trace.doAssert(test,
                                       "a: " + aA + ", " + iParent + ", "
                                       + iLeft + ", " + iRight + " b: " + bA
                                       + ", " + ((DiskNode) n).iParent + ", "
                                       + ((DiskNode) n).iLeft + ", "
                                       + ((DiskNode) n).iRight);
                    }
                }
            }
        }
*/
        return this == n
               || (n != null && getKey() == ((DiskNode) n).getKey());
    }

    void write(RowOutputInterface out) throws IOException {

        if (Trace.DOASSERT) {

            // fredt - assert not correct - row can be deleted from one index but
            // not yet deleted from other indexes while the process of finding
            // the node is in progress which may require saving the row
            // to make way for new rows in the cache
            // Trace.doAssert(iBalance != -2);
        }

        out.writeIntData(iBalance);
        out.writeIntData((iLeft == NO_POS) ? 0
                                           : iLeft);
        out.writeIntData((iRight == NO_POS) ? 0
                                            : iRight);
        out.writeIntData((iParent == NO_POS) ? 0
                                             : iParent);
    }

    Node getUpdatedNode() throws HsqlException {

        Row row = rData.getUpdatedRow();

        return row == null ? null
                           : row.getNode(iId);
    }

    void writeTranslate(RowOutputInterface out, IntLookup lookup) {

        out.writeIntData(iBalance);
        writeTranslatePointer(iLeft, out, lookup);
        writeTranslatePointer(iRight, out, lookup);
        writeTranslatePointer(iParent, out, lookup);
    }

    private void writeTranslatePointer(int pointer, RowOutputInterface out,
                                       IntLookup lookup) {

        int newPointer = 0;

        if (pointer != Node.NO_POS) {
            newPointer = lookup.lookupFirstEqual(pointer);
        }

        out.writeIntData(newPointer);
    }
}