Quadcap Embeddable Database

com/quadcap/sql/JoinNaturalRow.java

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package com.quadcap.sql;

/* Copyright 1999 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import java.util.Vector;

import java.sql.SQLException;

import com.quadcap.sql.types.Value;

import com.quadcap.util.Debug;

/**
 * A row containing a natural join, all columns from each of two cursors,
 * with only one instance of the join columns.
 *
 * @author Stan Bailes
 */
public class JoinNaturalRow extends Row {
    Row                                 a;
    Row                                 b;
    int                                 aSize;
    int[]                               aMap;
    int[]                               bMap;

    /**
     * @param a the left row
     * @param b the right row
     * @param aMap map columns from their join row position to their position
     *             in the left row. Zero based.
     * @param bMap map columns from their join row offset to their position
     *             in the right row. Zero based.
     */
    public JoinNaturalRow(Row a, Row b, int[] aMap, int[] bMap) {
        this.a = a;
        this.aSize = a.size();
        this.b = b;
        this.aMap = aMap;
        this.bMap = bMap;
    }

    public void setA(Row a) {
        this.a = a;
    }
    public void setB(Row b) {
        this.b = b;
    }

    public int size() { return aSize + bMap.length; }

    public Value item(int i) throws SQLException {
        if (i < 1 || i > size()) {
            throw new SQLException("bad column: " + i, "42000");
        }
        if (i <= aSize) {
            return a.item(aMap[i-1]);
        } else {
            return b.item(bMap[i - aSize - 1]);
        }
    }

    public void set(int i, Value val) throws SQLException {
        if (i < 1 || i > size()) {
            throw new SQLException("bad column: " + i, "42000");
        }
        if (i <= aSize) a.set(aMap[i-1], val);
        else b.set(bMap[i - aSize - 1], val);
    }
}