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/*
 * Copyright (c) 1998-2018 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.db.sql;

import com.caucho.db.Database;
import com.caucho.db.table.Column;
import com.caucho.db.table.Table;
import com.caucho.db.table.TableIterator;
import com.caucho.db.xa.DbTransaction;
import com.caucho.util.SQLExceptionWrapper;

import java.io.IOException;
import java.sql.SQLException;
import java.util.logging.Logger;

class UpdateQuery extends Query {
  private static final Logger log
    = Logger.getLogger(UpdateQuery.class.getName());

  private final Table _table;
  private SetItem []_setItems;

  UpdateQuery(Database db, String sql, Table table)
    throws SQLException
  {
    super(db, sql, null);

    _table = table;

    setFromItems(new FromItem[] { new FromItem(table, table.getName()) });
  }

  public void setSetItems(SetItem []setItems)
  {
    _setItems = setItems;
  }

  public boolean isReadOnly()
  {
    return false;
  }

  /**
   * Binds the query.
   */
  protected void bind()
    throws SQLException
  {
    super.bind();

    for (int i = 0; i < _setItems.length; i++) {
      Expr expr = _setItems[i].getExpr();
      
      expr = expr.bind(this);

      _setItems[i].setExpr(expr);
    }
  }

  /**
   * Executes the query.
   */
  public void execute(QueryContext context, DbTransaction xa)
    throws SQLException
  {
    int count = 0;
    SetItem []setItems = _setItems;
    TableIterator []rows = new TableIterator[1];
    rows[0] = _table.createTableIterator();
    context.init(xa, rows, isReadOnly());
    
    try {
      synchronized (_table) {
        try {
          if (! start(rows, rows.length, context, xa)) {
            return;
          }

          do {
            context.lock();

            try {
              if (! isSelect(context)) {
                continue;
              }

              TableIterator iter = rows[0];
              // iter.setDirty();

              for (int i = 0; i < setItems.length; i++) {
                Column column = setItems[i].getColumn();
                Expr expr = setItems[i].getExpr();

                column.set(xa, iter, expr, context);
              }
            } finally {
              context.unlock();
            }
	    
            context.setRowUpdateCount(++count);
          } while (nextTuple(rows, rows.length, context, xa));
        } catch (IOException e) {
          throw new SQLExceptionWrapper(e);
        } finally {
          // autoCommitWrite must be before freeRows in case freeRows
          // throws an exception
          context.close();

          freeRows(rows, rows.length);
        }
      }
    } finally {
      _table.wakeWriter();
    }
  }

  public String toString()
  {
    StringBuilder cb = new StringBuilder();
    cb.append("UpdateQuery[");
    if (_whereExpr != null) {
      cb.append(",where:" + _whereExpr);
    }
    cb.append("]");
    
    return cb.toString();
  }
}