/*
* Copyright (c) 1998-2011 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.amber.collection;
import com.caucho.amber.AmberQuery;
import com.caucho.amber.AmberRuntimeException;
import com.caucho.amber.manager.AmberConnection;
import com.caucho.amber.query.UserQuery;
import com.caucho.util.Alarm;
import java.sql.SQLException;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
/**
* Represents a lazy collection.
*/
public class CollectionImpl<E> extends AbstractList<E>
implements AmberCollection
{
private transient AmberQuery _query;
private transient AmberConnection _aConn;
private ArrayList<E> _values = new ArrayList<E>();
private transient long _expireTime;
public CollectionImpl(AmberConnection aConn, String query)
{
_aConn = aConn;
// jpa/0s2j
if (query != null) {
try {
_query = _aConn.prepareQuery(query);
} catch (SQLException e) {
throw new AmberRuntimeException(e);
}
}
}
public CollectionImpl(AmberQuery query)
{
_query = query;
// jpa/0s2k
if (_query != null)
setSession(((UserQuery) _query).getConnection());
}
/**
* Sets the session.
*/
public void setSession(AmberConnection aConn)
{
_aConn = aConn;
if (_aConn != null)
_aConn.register(this);
}
/**
* Returns the session.
*/
public AmberConnection getSession()
{
return _aConn;
}
/**
* Returns the query.
*/
public AmberQuery getQuery()
{
return _query;
}
/**
* Returns the number of items in the collection.
*/
public int size()
{
fill();
return _values.size();
}
/**
* Returns an iterator of the items.
*/
public Iterator<E> iterator()
{
fill();
return new ValuesIterator(_values);
}
/**
* Returns an iterator of the items.
*/
public E get(int index)
{
fill();
return _values.get(index);
}
/**
* Adds an item to the collection.
*/
public boolean add(E o)
{
fill();
return _values.add(o);
}
/**
* Adds an item to the collection.
*/
public boolean addAll(int index,
Collection<? extends E> collection)
{
fill();
// jpa/0i60
if (collection == null)
return true;
return _values.addAll(index, collection);
}
/**
* Clears the collection.
*/
public void clear()
{
_values.clear();
_expireTime = Alarm.getCurrentTime();
}
/**
* Updates the collection.
*/
public void update()
{
_expireTime = 0;
}
protected boolean isValid()
{
return Alarm.getCurrentTime() <= _expireTime;
}
/**
* Detaches the collection.
*/
public void detach()
{
_aConn = null;
_query = null;
}
private void fill()
{
// jpa/0s2i
if (_query == null)
return;
// If it is detached should not be updated.
if (_aConn == null)
return;
if (Alarm.getCurrentTime() <= _expireTime)
return;
try {
_expireTime = Alarm.getCurrentTime();
((UserQuery) _query).setSession(_aConn);
_values.clear();
_query.list((ArrayList) _values);
} catch (SQLException e) {
throw new AmberRuntimeException(e);
}
}
private Object writeReplace()
{
return _values;
}
class ValuesIterator implements Iterator {
private ArrayList<E> _values;
private int i = 0;
ValuesIterator(ArrayList<E> values)
{
_values = new ArrayList<E>(values);
}
public boolean hasNext()
{
return i < _values.size();
}
public E next()
{
if (i < _values.size())
return _values.get(i++);
else
return null;
}
public void remove()
{
CollectionImpl.this.remove(_values.get(i - 1));
}
}
}