HSQLDB example source code file (Node.java)

This example HSQLDB source code file (Node.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

disknode, hsqlexception, hsqlexception, io, ioexception, ioexception, memorynode, memorynode, no_pos, node, node, object, pointernode, rowinputinterface, table

The HSQLDB Node.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.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
// fredt@users 20021215 - doc 1.7.2 - javadoc comments

/**
 *  The parent for all AVL node implementations, features factory methods for
 *  its subclasses. Subclasses of Node vary in the way they hold
 *  references to other Nodes in the AVL tree, or to their Row data.<br>
 *
 *  nNext links the Node objects belonging to different indexes for each
 *  table row. It is used solely by Row to locate the node belonging to a
 *  particular index.
 *
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version 1.7.2
 * @since Hypersonic SQL
 */
abstract class Node {

    static final int NO_POS = CachedRow.NO_POS;
    int              iBalance;    // currently, -2 means 'deleted'
    Node             nNext;       // node of next index (nNext==null || nNext.iId=iId+1)

    static final Node newNode(Row r, int id, Table t) {

        switch (t.getIndexType()) {

            case Index.MEMORY_INDEX :
                return new MemoryNode(r);

            case Index.POINTER_INDEX :
                return new PointerNode((CachedRow) r, id);

            case Index.DISK_INDEX :
            default :
                return new DiskNode((CachedRow) r, id);
        }
    }

    static final Node newNode(Row r, RowInputInterface in, int id,
                              Table t) throws IOException, HsqlException {

        switch (t.getIndexType()) {

            case Index.MEMORY_INDEX :
                return new MemoryNode(r);

            case Index.POINTER_INDEX :
                return new PointerNode((CachedRow) r, id);

            case Index.DISK_INDEX :
            default :
                return new DiskNode((CachedRow) r, in, id);
        }
    }

    /**
     *  This method unlinks the Node from the other Nodes in the same Index
     *  and from the Row.
     *
     *  It must keep the links between the Nodes in different Indexes.
     */
    abstract void delete();

    /**
     *  File offset of Node. Used with CachedRow objects only
     */
    abstract int getKey();

    /**
     *  Return the Row Object that is linked to this Node.
     */
    abstract Row getRow() throws HsqlException;

    /**
     *  Getters and setters for AVL index operations.
     */
    abstract boolean isLeft(Node node) throws HsqlException;

    abstract boolean isRight(Node node) throws HsqlException;

    abstract Node getLeft() throws HsqlException;

    abstract void setLeft(Node n) throws HsqlException;

    abstract Node getRight() throws HsqlException;

    abstract void setRight(Node n) throws HsqlException;

    abstract Node getParent() throws HsqlException;

    abstract void setParent(Node n) throws HsqlException;

    final int getBalance() throws HsqlException {

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

        return iBalance;
    }

    abstract void setBalance(int b) throws HsqlException;

    abstract boolean isRoot();

    abstract boolean isFromLeft() throws HsqlException;

    /**
     *  Returns the database table data for this Node
     *
     */
    abstract Object[] getData() throws HsqlException;

    abstract boolean equals(Node n);

    /**
     *  Returns the Node Object that currently represents this Node in the
     *  AVL index structure. In current implementations of Node this is
     *  always the same as the this Object for MEMORY and TEXT tables but can
     *  be a different Object for CACHED tables, where DiskNode Objects may
     *  be freed from the Cache. Calling this method returns a Node with
     *  currently valid pointers to its linked AVL Nodes.
     *
     */
    Node getUpdatedNode() throws HsqlException {
        return this;
    }

    /**
     *  Writes out the node in an implementation dependent way.
     */
    abstract void write(RowOutputInterface out) throws IOException;

    boolean isDeleted() {
        return iBalance == -2;
    }
}