IndexDescriptions.java :  » Database-DBMS » smallsql » smallsql » database » Java Open Source

/* =============================================================
 * SmallSQL : a free Java DBMS library for the Java(tm) platform
 * =============================================================
 *
 * (C) Copyright 2004-2007, by Volker Berlin.
 *
 * Project Info:  http://www.smallsql.de/
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------------
 * IndexDescriptions.java
 * ---------------
 * Author: Volker Berlin
 * 
 * Created on 23.04.2005
 */
package smallsql.database;

import java.sql.SQLException;
import smallsql.database.language.Language;

/**
 * A typed implementation of Arraylist for IndexDescription.
 * 
 * @author Volker Berlin
 *
 */
class IndexDescriptions {
  private int size;
  private IndexDescription[] data;
    /** Only one primary Key per Table are valid */
    private boolean hasPrimary;
  
  
  IndexDescriptions(){
    data = new IndexDescription[4];
  }
  

  final int size(){
    return size;
  }
  

  final IndexDescription get(int idx){
    // SAVER: use SmallSQLException
    if (idx >= size)
      throw new IndexOutOfBoundsException("Column index: "+idx+", Size: "+size);
    return data[idx];
  }
  
  
  final void add(IndexDescription descr) throws SQLException{
    if(size >= data.length ){
      resize(size << 1);
    }
        if(hasPrimary && descr.isPrimary()){
            throw SmallSQLException.create(Language.PK_ONLYONE);
        }
        hasPrimary = descr.isPrimary();
    data[size++] = descr;
  }
  
  
  private final void resize(int newSize){
    IndexDescription[] dataNew = new IndexDescription[newSize];
    System.arraycopy(data, 0, dataNew, 0, size);
    data = dataNew;    
  }
  
  
  final IndexDescription findBestMatch(Strings columns){
    int bestFactor = Integer.MAX_VALUE;
    int bestIdx = 0;
    for(int i=0; i<size; i++){
      int factor = data[i].matchFactor(columns);
      if(factor == 0) 
        return data[i];
      
      if(factor < bestFactor){
        bestFactor = factor;
        bestIdx = i;
      }
    }
    if(bestFactor == Integer.MAX_VALUE)
      return null;
    else
      return data[bestIdx];
  }


  /**
   * Create all the indexes. This means a file for every index is save.
   * @param database 
   * @param tableView
   * @see IndexDescription#setTableView
   */
  void create(Database database, TableView tableView) throws Exception{
    for(int i=0; i<size; i++){
      data[i].create(database, tableView);
    }
  }


  void drop(Database database) throws Exception {
    for(int i=0; i<size; i++){
      data[i].drop(database);
    }
  }


    void close() throws Exception{
        for(int i=0; i<size; i++){
            data[i].close();
        }
    }


    void add(IndexDescriptions indexes) throws SQLException {
        for(int i=0; i<indexes.size; i++){
            add(indexes.data[i]);
        }
    }
}