svn commit: r409460 - /struts/shale/trunk/core-library/src/java/org/apache/shale/view/AbstractFacesBean.java

[cr...@apache.org]

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 {@link 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 {@link 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);
 
     }