Quadcap Embeddable Database

com/quadcap/sql/ItemsRow.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.sql.types.ValueNull;

import com.quadcap.util.Debug;

/**
 * Part of the 'ItemCursor' implementation, this implements a row that
 * is a mapped Essentially, a vector with one-based indices.
 *
 * @author Stan Bailes
 */
public class ItemsRow extends Row {
    Session                             session;
    Vector                              items;
    Cursor                              cursor;
    Row                                 myRow;
    Row                                 baseRow;
    int[]                               map;
    
    public ItemsRow(Session session, Vector items, Cursor cursor,
                    Row r, int[] map) throws SQLException {
        this.session = session;
        this.items = items;
        this.cursor = cursor;
        this.map = map;
        this.myRow = new Row(items.size());
        if (r == null && cursor != null) {
            r = new Row(cursor.getColumnCount());
            for (int i = 1; i <= r.size(); i++) r.set(i, ValueNull.valueNull);
        }
        this.nextRow(r);
    }

    Row getBaseRow() { return baseRow; }
    
    public void nextRow(Row r) throws SQLException {
        this.baseRow = r;
        for (int i = 1; i <= size(); i++) {
            myRow.set(i, getItem(r, i));
        }
    }
    
    public int size() { return map.length; }

    public Value item(int i) throws SQLException {
        return myRow.item(i);
    }
    
    public Value getItem(Row r, int i) throws SQLException {
        int pos = map[i-1];
        if (pos < 0) {
            SelectItem item = (SelectItem)items.elementAt(i-1);
            Expression e = item.getExpression();
            return e.getValue(session, cursor);
        } else if (r != null) {
            return r.item(pos);
        } else {
            return new ValueNull();
        }
    }

    public void set(int i, Value val) throws SQLException {
        int pos = map[i-1];
        if (pos < 0) {
            throw new SQLException("Not updatable: " +
                                   items.elementAt(i-1),
                                   "42000");
        }
        myRow.set(i, val);
        baseRow.set(map[i-1], val);
    }

    public boolean isUpdateable(int i) {
        return map[i-1] >= 0;
    }
}