/*
* 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.expr;
import com.caucho.amber.field.ElementCollectionField;
import com.caucho.amber.query.FromItem;
import com.caucho.amber.query.QueryParser;
import com.caucho.amber.table.LinkColumns;
import com.caucho.amber.table.AmberTable;
import com.caucho.amber.type.AmberType;
import com.caucho.amber.type.BeanType;
import com.caucho.amber.type.ElementType;
import com.caucho.amber.type.EntityType;
import com.caucho.util.CharBuffer;
/**
* Expression to a collection of rows
*
* The relation is maintained by a link from the child objects
* to the parent object.
*/
public class ElementCollectionExpr extends AbstractPathExpr {
private PathExpr _parent;
// Link from the target to the parent
private LinkColumns _linkColumns;
private ElementType _targetType;
private FromItem _fromItem;
private FromItem _childFromItem;
/**
* Creates a new expression to the child objects.
*/
public ElementCollectionExpr(QueryParser parser,
PathExpr parent,
LinkColumns linkColumns,
ElementType targetType)
{
_parent = parent;
_targetType = targetType;
_linkColumns = linkColumns;
}
/**
* Returns the link columns.
*/
public LinkColumns getLinkColumns()
{
return _linkColumns;
}
/**
* Returns the expr type.
*/
public AmberType getType()
{
return _linkColumns.getSourceTable().getType();
}
/**
* Creates an id expression.
*/
@Override
public IdExpr createId(FromItem fromItem)
{
return new ElementCollectionIdExpr(fromItem, this);
}
/**
* Returns the expr type.
*/
public BeanType getTargetType()
{
return _targetType;
}
/**
* Returns true if the expression uses the from item.
*/
public boolean usesFrom(FromItem from, int type, boolean isNot)
{
return (from == _childFromItem
|| type == IS_INNER_JOIN && _parent.usesFrom(from, type));
}
/**
* Returns the parent.
*/
public PathExpr getParent()
{
return _parent;
}
/**
* Binds the expression as a select item.
*/
public AmberExpr bindSelect(QueryParser parser)
{
return bindSelect(parser, null);
}
/**
* Binds the expression as a select item.
*/
public PathExpr bindSelect(QueryParser parser, String id)
{
if (_fromItem != null)
return this;
_fromItem = _parent.bindSubPath(parser);
AmberTable sourceTable = _linkColumns.getSourceTable();
_childFromItem = parser.addFromItem(sourceTable, id);
JoinExpr joinExpr;
joinExpr = new OneToManyJoinExpr(_linkColumns,
_childFromItem,
_fromItem);
_childFromItem.setJoinExpr(joinExpr);
_childFromItem.setCollectionExpr(this);
return this;
}
/**
* Returns the child from item.
*/
public FromItem getChildFromItem()
{
return _childFromItem;
}
/**
* Binds the expression as a subpath.
*/
public FromItem bindSubPath(QueryParser parser)
{
if (_childFromItem == null)
bindSelect(parser, null);
return _childFromItem;
}
/**
* Returns the table.
*/
public AmberTable getTable()
{
// return _field.getTable();
return _fromItem.getTable();
}
/**
* Generates the where expression.
*/
public void generateWhere(CharBuffer cb)
{
throw new UnsupportedOperationException(getClass().getName());
}
/**
* Generates the (update) where expression.
*/
public void generateUpdateWhere(CharBuffer cb)
{
generateWhere(cb);
}
/**
* Generates the having expression.
*/
public void generateHaving(CharBuffer cb)
{
generateWhere(cb);
}
/**
* Generates the where expression.
*/
public void generateSelect(CharBuffer cb)
{
String id = _childFromItem.getName();
ElementCollectionField field
= (ElementCollectionField) _targetType.getField();
cb.append(field.generateLoadSelect(id));
}
public boolean equals(Object o)
{
if (o == null || ! getClass().equals(o.getClass()))
return false;
ElementCollectionExpr eltCollection = (ElementCollectionExpr) o;
return (_parent.equals(eltCollection._parent) &&
_linkColumns.equals(eltCollection._linkColumns));
}
public String toString()
{
return (getClass().getSimpleName()
+ "[" + _parent + "," + _linkColumns + "]");
}
}