Author: craigmcc
Date: Thu May 25 13:40:00 2006
New Revision: 409460
URL: http://svn.apache.org/viewvc?rev=409460&view=rev
Log:
Add convenience methods to save and restore arbitrary (but Serializable)
data objects under an attribute of the view root component. This is very
useful for passing information from a rendered version of a view to the
following request that will process a postback, without having to store it
in session scope or explicitly modify the view to include something like
<h:inputHidden/>.
If you use ViewController, you would typically call saveData("key", value)
in the prerender() method, and call retrieveData("key") in the preprocess()
method.
Modified:
struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java
Modified:
struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java
URL:
http://svn.apache.org/viewvc/struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java?rev=409460&r1=409459&r2=409460&view=diff
==============================================================================
---
struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java
(original)
+++
struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java
Thu May 25 13:40:00 2006
@@ -16,12 +16,14 @@
package org.apache.shale.view;
+import java.util.HashMap;
import java.util.Map;
import javax.faces.FactoryFinder;
import javax.faces.application.Application;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
+import javax.faces.component.UIViewRoot;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;
@@ -213,6 +215,78 @@
ValueBinding vb = getApplication().createValueBinding(expr);
vb.setValue(getFacesContext(), value);
+
+ }
+
+
+ // ----------------------------------------------- Save/Restore Data
Methods
+
+
+ /**
+ * <p>The attribute name under which saved data will be stored on the
+ * view root component.</p>
+ */
+ private static final String DATA_KEY = "org.apache.shale.DATA";
+
+
+
+ /**
+ * <p>Return the data object stored (typically when the component tree
+ * was previously rendered) under the specified key, if any; otherwise,
+ * return <code>null</code>.</p>
+ *
+ * <p><strong>IMPLEMENTATION NOTE:</strong> Data objects will become
+ * available only after the <em>Restore View</em> phase of the request
+ * processing lifecycle has been completed. A common place to reinitialize
+ * state information, then, would be in the <code>preprocess()</code>
+ * event handler of a [EMAIL PROTECTED] ViewController} backing bean.</p>
+ *
+ * @param key Key under which to retrieve the requested data
+ */
+ public Object retrieveData(String key) {
+
+ FacesContext context = getFacesContext();
+ if (context == null) {
+ return null;
+ }
+ UIViewRoot view = context.getViewRoot();
+ if (view == null) {
+ return null;
+ }
+ Map map = (Map) view.getAttributes().get(DATA_KEY);
+ if (map != null) {
+ return map.get(key);
+ } else {
+ return null;
+ }
+
+ }
+
+
+ /**
+ * <p>Save the specified data object (which <strong>MUST</strong> be
+ * <code>Serializable</code>) under the specified key, such that it can
+ * be retrieved (via <code>getData()</code>) on a s subsequent request
+ * immediately after the component tree has been restored.</p>
+ *
+ * <p><strong>IMPLEMENTATION NOTE:</strong> In order to successfully save
+ * data objects, this method must be called before the <em>Render
Response</em>
+ * phase of the request processing lifecycle is executed. A common
scenario
+ * is to save state information in the <code>prerender()</code> event
handler
+ * of a [EMAIL PROTECTED] ViewController} backing bean.</p>
+ *
+ * @param key Key under which to store the requested data
+ * @param data Data object to be stored
+ */
+ public void saveData(String key, Object data) {
+
+ Map map = (Map)
+ getFacesContext().getViewRoot().getAttributes().get(DATA_KEY);
+ if (map == null) {
+ map = new HashMap();
+ getFacesContext().getViewRoot().getAttributes().put(DATA_KEY, map);
+ }
+ map.put(key, data);
}
