Merge tag 'v2.3.20' into testing

[gpl/argeo-jcr.git] / swt / org.argeo.tool.devops.e4 / src / org / argeo / cms / ui / eclipse / forms / IFormPart.java

diff --git a/swt/org.argeo.tool.devops.e4/src/org/argeo/cms/ui/eclipse/forms/IFormPart.java b/swt/org.argeo.tool.devops.e4/src/org/argeo/cms/ui/eclipse/forms/IFormPart.java
new file mode 100644 (file)
index 0000000..954cc03
--- /dev/null
+++ b/swt/org.argeo.tool.devops.e4/src/org/argeo/cms/ui/eclipse/forms/IFormPart.java
@@ -0,0 +1,108 @@
+package org.argeo.cms.ui.eclipse.forms;
+
+/**
+ * Classes that implement this interface can be added to the managed form and
+ * take part in the form life cycle. The part is initialized with the form and
+ * will be asked to accept focus. The part can receive form input and can elect
+ * to do something according to it (for example, select an object that matches
+ * the input).
+ * <p>
+ * The form part has two 'out of sync' states in respect to the model(s) that
+ * feed the form: <b>dirty</b> and <b>stale</b>. 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).
+ * <p>
+ * 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 <code>true</code> if the part has selected and revealed the
+        *         input object, <code>false</code> 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).
+        * <p>
+        * 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 <code>true</code> if the part needs refreshing,
+        *         <code>false</code> 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();
+}