1 package org.argeo.cms.ui.eclipse.forms;
2
3 /**
4 * Classes that implement this interface can be added to the managed form and
5 * take part in the form life cycle. The part is initialized with the form and
6 * will be asked to accept focus. The part can receive form input and can elect
7 * to do something according to it (for example, select an object that matches
8 * the input).
9 * <p>
10 * The form part has two 'out of sync' states in respect to the model(s) that
11 * feed the form: <b>dirty</b> and <b>stale</b>. When a part is dirty, it
12 * means that the user interacted with it and now its widgets contain state that
13 * is newer than the model. In order to sync up with the model, 'commit' needs
14 * to be called. In contrast, the model can change 'under' the form (as a result
15 * of some actions outside the form), resulting in data in the model being
16 * 'newer' than the content presented in the form. A 'stale' form part is
17 * brought in sync with the model by calling 'refresh'. The part is responsible
18 * for notifying the form when one of these states change in the part. The form
19 * reserves the right to handle this notification in the most appropriate way
20 * for the situation (for example, if the form is in a page of the multi-page
21 * editor, it may do nothing for stale parts if the page is currently not
22 * showing).
23 * <p>
24 * When the form is disposed, each registered part is disposed as well. Parts
25 * are responsible for releasing any system resources they created and for
26 * removing themselves as listeners from all event providers.
27 *
28 * @see IManagedForm
29 * @since 1.0
30 *
31 */
32 public interface IFormPart {
33 /**
34 * Initializes the part.
35 *
36 * @param form
37 * the managed form that manages the part
38 */
39 void initialize(IManagedForm form);
40
41 /**
42 * Disposes the part allowing it to release allocated resources.
43 */
44 void dispose();
45
46 /**
47 * Returns true if the part has been modified with respect to the data
48 * loaded from the model.
49 *
50 * @return true if the part has been modified with respect to the data
51 * loaded from the model
52 */
53 boolean isDirty();
54
55 /**
56 * If part is displaying information loaded from a model, this method
57 * instructs it to commit the new (modified) data back into the model.
58 *
59 * @param onSave
60 * indicates if commit is called during 'save' operation or for
61 * some other reason (for example, if form is contained in a
62 * wizard or a multi-page editor and the user is about to leave
63 * the page).
64 */
65 void commit(boolean onSave);
66
67 /**
68 * Notifies the part that an object has been set as overall form's input.
69 * The part can elect to react by revealing or selecting the object, or do
70 * nothing if not applicable.
71 *
72 * @return <code>true</code> if the part has selected and revealed the
73 * input object, <code>false</code> otherwise.
74 */
75 boolean setFormInput(Object input);
76
77 /**
78 * Instructs form part to transfer focus to the widget that should has focus
79 * in that part. The method can do nothing (if it has no widgets capable of
80 * accepting focus).
81 */
82 void setFocus();
83
84 /**
85 * Tests whether the form part is stale and needs refreshing. Parts can
86 * receive notification from models that will make their content stale, but
87 * may need to delay refreshing to improve performance (for example, there
88 * is no need to immediately refresh a part on a form that is current on a
89 * hidden page).
90 * <p>
91 * It is important to differentiate 'stale' and 'dirty' states. Part is
92 * 'dirty' if user interacted with its editable widgets and changed the
93 * values. In contrast, part is 'stale' when the data it presents in the
94 * widgets has been changed in the model without direct user interaction.
95 *
96 * @return <code>true</code> if the part needs refreshing,
97 * <code>false</code> otherwise.
98 */
99 boolean isStale();
100
101 /**
102 * Refreshes the part completely from the information freshly obtained from
103 * the model. The method will not be called if the part is not stale.
104 * Otherwise, the part is responsible for clearing the 'stale' flag after
105 * refreshing itself.
106 */
107 void refresh();
108 }