com.mchange.v1.db.sql.SimpleCursor Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java 0.2.11
*
* Copyright (C) 2015 Machinery For Change, Inc.
*
* Author: Steve Waldman
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of EITHER:
*
* 1) The GNU Lesser General Public License (LGPL), version 2.1, as
* published by the Free Software Foundation
*
* OR
*
* 2) The Eclipse Public License (EPL), version 1.0
*
* You may choose which license to accept if you wish to redistribute
* or modify this work. You may offer derivatives of this work
* under the license you have chosen, or you may provide the same
* choice of license which you have been offered here.
*
* This software 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.
*
* You should have received copies of both LGPL v2.1 and EPL v1.0
* along with this software; see the files LICENSE-EPL and LICENSE-LGPL.
* If not, the text of these licenses are currently available at
*
* LGPL v2.1: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* EPL v1.0: http://www.eclipse.org/org/documents/epl-v10.php
*
*/
package com.mchange.v1.db.sql;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mchange.v1.util.UIterator;
public abstract class SimpleCursor implements UIterator
{
ResultSet rs;
int available = -1; //1 true, 0 false, -1 unchecked
public SimpleCursor(ResultSet rs)
{this.rs = rs;}
public boolean hasNext() throws SQLException
{
ratchet();
return (available == 1);
}
public Object next() throws SQLException
{
ratchet();
Object out = objectFromResultSet(rs);
clear();
return out;
}
public void remove()
{throw new UnsupportedOperationException();}
public void close() throws Exception
{
rs.close();
rs = null;
}
public void finalize() throws Exception
{if (rs != null) this.close();}
protected abstract Object objectFromResultSet(ResultSet rs) throws SQLException;
private void ratchet() throws SQLException
{
if (available == -1)
available = (rs.next() ? 1 : 0);
}
private void clear()
{available = -1;}
}