/*
* 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.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.EntityType;
import com.caucho.amber.type.AmberType;
import com.caucho.util.CharBuffer;
/**
* Link expression to a new table
*/
public class ManyToOneExpr extends AbstractPathExpr {
private PathExpr _parent;
private LinkColumns _linkColumns;
private FromItem _fromItem;
private FromItem _childFromItem;
/**
* Creates a new unbound id expression.
*/
public ManyToOneExpr(PathExpr parent, LinkColumns linkColumns)
{
_parent = parent;
_linkColumns = linkColumns;
}
/**
* Returns the entity class.
*/
public EntityType getTargetType()
{
return _linkColumns.getTargetTable().getType();
}
/**
* Returns the entity class.
*/
public AmberType getType()
{
return getTargetType();
}
/**
* Binds the expression as a select item.
*/
public AmberExpr bindSelect(QueryParser parser)
{
_fromItem = _parent.bindSubPath(parser);
return this;
}
/**
* Return the parent from item.
*/
public FromItem getFromItem()
{
return _fromItem;
}
/**
* Returns the link columns.
*/
public LinkColumns getLinkColumns()
{
return _linkColumns;
}
/**
* Return the child from item.
*/
public FromItem getChildFromItem()
{
return _childFromItem;
}
/**
* Binds the expression as a subpath.
*/
public FromItem bindSubPath(QueryParser parser)
{
if (_childFromItem != null)
return _childFromItem;
ManyToOneExpr pathExpr = (ManyToOneExpr) parser.addPath(this);
if (pathExpr != this) {
_fromItem = pathExpr._fromItem;
_childFromItem = pathExpr._childFromItem;
return _childFromItem;
}
// XXX: handled at constructor?
_parent = _parent.bindSelect(parser, null);
bindSelect(parser, parser.createTableName());
return _childFromItem;
}
/**
* Binds the expression as a select item.
*/
public PathExpr bindSelect(QueryParser parser, String id)
{
if (_childFromItem != null)
return this;
if (_fromItem == null)
_fromItem = _parent.bindSubPath(parser);
AmberTable targetTable = _linkColumns.getTargetTable();
_childFromItem = parser.addFromItem(targetTable, id);
JoinExpr joinExpr;
joinExpr = new ManyToOneJoinExpr(_linkColumns,
_fromItem,
_childFromItem);
_childFromItem.setJoinExpr(joinExpr);
return this;
}
/**
* Returns true if the expression uses the from item.
*/
public boolean usesFrom(FromItem from, int type, boolean isNot)
{
return (_childFromItem == from && type == IS_INNER_JOIN
|| _fromItem == from
|| _parent.usesFrom(from, type));
}
/**
* Returns true if the item is forced to exist by the parent
*/
@Override
public boolean exists(FromItem from)
{
return (_fromItem == from
&& _parent.exists());
}
/**
* Returns the table.
*/
/*
public AmberTable getTable()
{
if (_childFromItem != null)
return _childFromItem.getTable();
else if (_fromItem != null)
return _fromItem.getTable();
else
return _parent.getTable();
}
*/
/**
* Generates the where expression.
*/
public void generateMatchArgWhere(CharBuffer cb)
{
if (_fromItem != null) {
cb.append(_linkColumns.generateMatchArgSQL(_fromItem.getName()));
}
else {
cb.append(_linkColumns.generateMatchArgSQL(_parent.getChildFromItem().getName()));
}
}
/**
* Generates the where expression.
*/
public void generateWhere(CharBuffer cb)
{
generateInternalWhere(cb, true);
}
/**
* Generates the (update) where expression.
*/
public void generateUpdateWhere(CharBuffer cb)
{
generateInternalWhere(cb, false);
}
/**
* Generates the select expression.
*/
// ejb/06q4
public void generateSelect(CharBuffer cb)
{
String tableName;
if (_fromItem != null)
tableName = _fromItem.getName();
else
tableName = _parent.getChildFromItem().getName();
cb.append(_linkColumns.generateSelectSQL(tableName));
}
/**
* Creates a load expression.
*/
@Override
public LoadExpr createLoad()
{
return new LoadEntityExpr(this);
}
/**
* Returns the parent.
*/
public PathExpr getParent()
{
return _parent;
}
public int hashCode()
{
return 65521 * _parent.hashCode() + _linkColumns.hashCode();
}
public boolean equals(Object o)
{
if (o == null || ! getClass().equals(o.getClass()))
return false;
ManyToOneExpr manyToOne = (ManyToOneExpr) o;
return (_parent.equals(manyToOne._parent) &&
_linkColumns.equals(manyToOne._linkColumns));
}
public String toString()
{
return "ManyToOneExpr[" + _childFromItem + "," + _fromItem + "," + _parent + "]";
}
//
// private
private void generateInternalWhere(CharBuffer cb,
boolean select)
{
if (_fromItem != null) {
if (select) {
cb.append(_fromItem.getName());
cb.append('.');
}
cb.append(_linkColumns.getColumns().get(0).getName());
}
else {
if (select)
super.generateWhere(cb);
else
super.generateUpdateWhere(cb);
}
}
}