01: /* Copyright (C) 2004 - 2007 db4objects Inc. http://www.db4o.com
02:
03: This file is part of the db4o open source object database.
04:
05: db4o is free software; you can redistribute it and/or modify it under
06: the terms of version 2 of the GNU General Public License as published
07: by the Free Software Foundation and as clarified by db4objects' GPL
08: interpretation policy, available at
09: http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10: Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11: Suite 350, San Mateo, CA 94403, USA.
12:
13: db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14: WARRANTY; without even the implied warranty of MERCHANTABILITY or
15: FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16: for more details.
17:
18: You should have received a copy of the GNU General Public License along
19: with this program; if not, write to the Free Software Foundation, Inc.,
20: 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21: package com.db4o.internal.fieldindex;
22:
23: import com.db4o.foundation.*;
24: import com.db4o.internal.*;
25: import com.db4o.internal.query.processor.*;
26:
27: public class IndexedPath extends IndexedNodeBase {
28:
29: public static IndexedNode newParentPath(IndexedNode next,
30: QCon constraint) {
31: if (!canFollowParent(constraint)) {
32: return null;
33: }
34: return new IndexedPath((QConObject) constraint.parent(), next);
35: }
36:
37: private static boolean canFollowParent(QCon con) {
38: final QCon parent = con.parent();
39: final FieldMetadata parentField = getYapField(parent);
40: if (null == parentField)
41: return false;
42: final FieldMetadata conField = getYapField(con);
43: if (null == conField)
44: return false;
45: return parentField.hasIndex()
46: && parentField.handlerClassMetadata(
47: con.transaction().container())
48: .isAssignableFrom(conField.containingClass());
49: }
50:
51: private static FieldMetadata getYapField(QCon con) {
52: QField field = con.getField();
53: if (null == field)
54: return null;
55: return field.getYapField();
56: }
57:
58: private IndexedNode _next;
59:
60: public IndexedPath(QConObject parent, IndexedNode next) {
61: super (parent);
62: _next = next;
63: }
64:
65: public Iterator4 iterator() {
66: return new IndexedPathIterator(this , _next.iterator());
67: }
68:
69: public int resultSize() {
70: throw new NotSupportedException();
71: }
72: }
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