/*
* Copyright (c) 1998-2010 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.AmberField;
import com.caucho.amber.field.IdField;
import com.caucho.amber.field.KeyManyToOneField;
import com.caucho.amber.field.KeyPropertyField;
import com.caucho.amber.query.FromItem;
import com.caucho.amber.query.QueryParser;
import com.caucho.amber.table.AmberColumn;
import com.caucho.amber.type.EntityType;
import com.caucho.util.CharBuffer;
/**
* Bound identifier expression.
*/
public class KeyManyToOneExpr extends AbstractPathExpr
implements IdFieldExpr {
private PathExpr _parent;
// identifier name value
private KeyManyToOneField _manyToOne;
private FromItem _fromItem;
private FromItem _childFromItem;
/**
* Creates a new unbound id expression.
*/
public KeyManyToOneExpr(PathExpr parent, KeyManyToOneField manyToOne)
{
_parent = parent;
_manyToOne = manyToOne;
}
/**
* Returns the parent expression.
*/
public PathExpr getParent()
{
return _parent;
}
/**
* Returns the name.
*/
public IdField getField()
{
return _manyToOne;
}
/**
* Returns the entity class.
*/
public EntityType getTargetType()
{
return _manyToOne.getEntityType();
}
/**
* Returns the column.
*/
public AmberColumn getColumn()
{
throw new UnsupportedOperationException();
}
/**
* Creates the expr from the path.
*/
public AmberExpr createField(QueryParser parser, String name)
{
AmberField field = getTargetType().getField(name);
if (field == null)
return null;
else if (field instanceof IdField) {
KeyPropertyField idField = _manyToOne.getIdField((IdField) field);
return idField.createExpr(parser, _parent);
}
else
return field.createExpr(parser, this);
}
/**
* Binds the expression as a select item.
*/
public AmberExpr bindSelect(QueryParser parser)
{
_fromItem = _parent.bindSubPath(parser);
return this;
}
/**
* 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;
KeyManyToOneExpr pathExpr = (KeyManyToOneExpr) parser.addPath(this);
if (pathExpr != this) {
_fromItem = pathExpr._fromItem;
_childFromItem = pathExpr._childFromItem;
return _childFromItem;
}
_fromItem = _parent.bindSubPath(parser);
if (_fromItem != null)
_childFromItem = _fromItem.getQuery().createFromItem(getTargetType().getTable(),
parser.createTableName());
else
_childFromItem = parser.getSelectQuery().createFromItem(getTargetType().getTable(),
parser.createTableName());
JoinExpr link = new ManyToOneJoinExpr(_manyToOne.getLinkColumns(),
_fromItem,
_childFromItem);
_childFromItem.setJoinExpr(link);
return _childFromItem;
}
/**
* Returns true if the expression uses the from item.
*/
public boolean usesFrom(FromItem from, int type, boolean isNot)
{
return from == _childFromItem || _parent.usesFrom(from, type);
}
/**
* Replaces linked join to eliminate a table.
*/
/*
public AmberExpr replaceJoin(JoinExpr join)
{
if (_parent instanceof IdExpr) {
return join.replace(this);
}
else
return super.replaceJoin(join);
}
*/
/**
* Returns the table.
*/
/*
public String getTable()
{
if (_childFromItem != null)
return _childFromItem.getName();
else if (_fromItem != null)
return _fromItem.getName();
else
return _parent.getChildFromItem().getName();
}
*/
/**
* Generates the where expression.
*/
public void generateMatchArgWhere(CharBuffer cb)
{
String table;
if (_fromItem != null)
table = _fromItem.getName();
else
table = _parent.getChildFromItem().getName();
cb.append(_manyToOne.getLinkColumns().generateMatchArgSQL(table));
}
public String toString()
{
return _parent + "." + getField();
}
public int hashCode()
{
return 65521 * _parent.hashCode() + getField().hashCode();
}
public boolean equals(Object o)
{
if (o == null || ! getClass().equals(o.getClass()))
return false;
KeyManyToOneExpr manyToOne = (KeyManyToOneExpr) o;
return (_parent.equals(manyToOne._parent) &&
getField().equals(manyToOne.getField()));
}
}