1 /*
2 * Copyright 2002 - 2007 JEuclid, http://jeuclid.sf.net
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /* $Id: AbstractElementWithDelegates.java,v bc1d5fde7b73 2009/06/01 14:40:54 maxberger $ */
18
19 package net.sourceforge.jeuclid.elements;
20
21 import java.util.List;
22
23 import net.sourceforge.jeuclid.elements.presentation.AbstractContainer;
24 import net.sourceforge.jeuclid.layout.LayoutableNode;
25
26 import org.apache.batik.dom.AbstractDocument;
27
28 /**
29 * Generic class for all mathobjects that can be represented using other Math
30 * objects. These math objects use a delegates for the actual display and
31 * calculations.
32 * <p>
33 * To use this class, overwrite {@link #createDelegates()} to create the
34 * delegate objects.
35 *
36 * @version $Revision: bc1d5fde7b73 $
37 */
38 public abstract class AbstractElementWithDelegates extends AbstractContainer {
39
40 // TODO: Re-Enable resetting delegates on changeHook!
41 private List<LayoutableNode> delegates;
42
43 /**
44 * Default constructor. Sets MathML Namespace.
45 *
46 * @param qname
47 * Qualified name.
48 * @param odoc
49 * Owner Document.
50 */
51 public AbstractElementWithDelegates(final String qname,
52 final AbstractDocument odoc) {
53 super(qname, odoc);
54 }
55
56 /**
57 * Overwrite this function in your implementation.
58 *
59 * @return a MathObject representing the real contents.
60 */
61 protected abstract List<LayoutableNode> createDelegates();
62
63 private void prepareDelegates() {
64 if (this.delegates == null) {
65 this.delegates = this.createDelegates();
66 for (final LayoutableNode element : this.delegates) {
67 ((JEuclidElement) element).setFakeParent(this);
68 }
69 }
70 }
71
72 /** {@inheritDoc} */
73 @Override
74 public List<LayoutableNode> getChildrenToLayout() {
75 this.prepareDelegates();
76 return this.delegates;
77 }
78
79 /** {@inheritDoc} */
80 @Override
81 public List<LayoutableNode> getChildrenToDraw() {
82 this.prepareDelegates();
83 return this.delegates;
84 }
85
86 }