+ * The form part has two 'out of sync' states in respect to the model(s) that + * feed the form: dirty and stale. When a part is dirty, it + * means that the user interacted with it and now its widgets contain state that + * is newer than the model. In order to sync up with the model, 'commit' needs + * to be called. In contrast, the model can change 'under' the form (as a result + * of some actions outside the form), resulting in data in the model being + * 'newer' than the content presented in the form. A 'stale' form part is + * brought in sync with the model by calling 'refresh'. The part is responsible + * for notifying the form when one of these states change in the part. The form + * reserves the right to handle this notification in the most appropriate way + * for the situation (for example, if the form is in a page of the multi-page + * editor, it may do nothing for stale parts if the page is currently not + * showing). + *
+ * When the form is disposed, each registered part is disposed as well. Parts
+ * are responsible for releasing any system resources they created and for
+ * removing themselves as listeners from all event providers.
+ *
+ * @see IManagedForm
+ * @since 1.0
+ *
+ */
+public interface IFormPart {
+ /**
+ * Initializes the part.
+ *
+ * @param form
+ * the managed form that manages the part
+ */
+ void initialize(IManagedForm form);
+
+ /**
+ * Disposes the part allowing it to release allocated resources.
+ */
+ void dispose();
+
+ /**
+ * Returns true if the part has been modified with respect to the data
+ * loaded from the model.
+ *
+ * @return true if the part has been modified with respect to the data
+ * loaded from the model
+ */
+ boolean isDirty();
+
+ /**
+ * If part is displaying information loaded from a model, this method
+ * instructs it to commit the new (modified) data back into the model.
+ *
+ * @param onSave
+ * indicates if commit is called during 'save' operation or for
+ * some other reason (for example, if form is contained in a
+ * wizard or a multi-page editor and the user is about to leave
+ * the page).
+ */
+ void commit(boolean onSave);
+
+ /**
+ * Notifies the part that an object has been set as overall form's input.
+ * The part can elect to react by revealing or selecting the object, or do
+ * nothing if not applicable.
+ *
+ * @return true if the part has selected and revealed the
+ * input object, false otherwise.
+ */
+ boolean setFormInput(Object input);
+
+ /**
+ * Instructs form part to transfer focus to the widget that should has focus
+ * in that part. The method can do nothing (if it has no widgets capable of
+ * accepting focus).
+ */
+ void setFocus();
+
+ /**
+ * Tests whether the form part is stale and needs refreshing. Parts can
+ * receive notification from models that will make their content stale, but
+ * may need to delay refreshing to improve performance (for example, there
+ * is no need to immediately refresh a part on a form that is current on a
+ * hidden page).
+ *
+ * It is important to differentiate 'stale' and 'dirty' states. Part is
+ * 'dirty' if user interacted with its editable widgets and changed the
+ * values. In contrast, part is 'stale' when the data it presents in the
+ * widgets has been changed in the model without direct user interaction.
+ *
+ * @return true if the part needs refreshing,
+ * false otherwise.
+ */
+ boolean isStale();
+
+ /**
+ * Refreshes the part completely from the information freshly obtained from
+ * the model. The method will not be called if the part is not stale.
+ * Otherwise, the part is responsible for clearing the 'stale' flag after
+ * refreshing itself.
+ */
+ void refresh();
+}