#469: add o:viewAction message

src/main/java/org/omnifaces/component/input/ViewAction.java

@@ -12,10 +12,22 @@
  */
 package org.omnifaces.component.input;
 
+import static org.omnifaces.util.Messages.addFlashGlobalWarn;
+import static org.omnifaces.util.Utils.isEmpty;
+
+import java.io.IOException;
+
 import javax.faces.component.FacesComponent;
 import javax.faces.component.UIViewAction;
+import javax.faces.context.ExternalContext;
+import javax.faces.context.ExternalContextWrapper;
+import javax.faces.context.FacesContext;
+import javax.faces.context.FacesContextWrapper;
+import javax.faces.event.ActionEvent;
 import javax.faces.event.FacesEvent;
 
+import org.omnifaces.util.State;
+
 /**
  * <p>
  * The <code>&lt;o:viewAction&gt;</code> is a component that extends the standard <code>&lt;f:viewAction&gt;</code> and
@@ -50,30 +62,101 @@
  * &lt;o:viewAction action="otherpage" if="#{bean.property eq null}" /&gt;
  * </pre>
  *
+ * <h3>Messaging</h3>
+ * <p>
+ * You can use the <code>message</code> attribute to add a global flash warning message.
+ * <pre>
+ * &lt;o:viewAction ... message="Please use a valid link from within the site" /&gt;
+ * </pre>
+ * <p>
+ * Note that the message will only be shown when the redirect has actually taken place. The support was added in
+ * OmniFaces 3.2.
+ *
  * @author Bauke Scholtz
  * @since 2.2
  */
 @FacesComponent(ViewAction.COMPONENT_TYPE)
 public class ViewAction extends UIViewAction {
 
-	// Public constants -----------------------------------------------------------------------------------------------
+	// Constants ------------------------------------------------------------------------------------------------------
 
 	public static final String COMPONENT_TYPE = "org.omnifaces.component.input.ViewAction";
 
+	enum PropertyKeys {
+		message
+	}
+
+	// Variables ------------------------------------------------------------------------------------------------------
+
+	private final State state = new State(getStateHelper());
+
 	// Actions --------------------------------------------------------------------------------------------------------
 
 	/**
 	 * Only broadcast the action event when {@link UIViewAction#isRendered()} returns <code>true</code>. The default
 	 * implementation will always broadcast. The {@link UIViewAction#isRendered()} is by default only considered during
 	 * {@link #decode(javax.faces.context.FacesContext)}.
+	 * <p>
+	 * If the action event performs any redirect, then add any {@link #getMessage()} as a global flash warning message.
 	 */
 	@Override
 	public void broadcast(FacesEvent event) {
 		if (super.isRendered()) {
-			super.broadcast(event);
+			String message = getMessage();
+			super.broadcast(isEmpty(message) ? event : new RedirectMessageEvent(event, message));
 		}
 	}
 
+	private static class RedirectMessageEvent extends ActionEvent {
+
+		private static final long serialVersionUID = 1L;
+
+		private FacesContext facesContext;
+
+		public RedirectMessageEvent(FacesEvent wrapped, String message) {
+			super(wrapped.getComponent());
+			this.facesContext = new RedirectMessageFacesContext(wrapped.getFacesContext(), message);
+		}
+
+		@Override
+		public FacesContext getFacesContext() {
+			return facesContext;
+		}
+	}
+
+	private static class RedirectMessageFacesContext extends FacesContextWrapper {
+
+		private ExternalContext externalContext;
+
+		public RedirectMessageFacesContext(FacesContext wrapped, String message) {
+			super(wrapped);
+			this.externalContext = new RedirectMessageExternalContext(getWrapped().getExternalContext(), message);
+		}
+
+		@Override
+		public ExternalContext getExternalContext() {
+			return externalContext;
+		}
+	}
+
+	private static class RedirectMessageExternalContext extends ExternalContextWrapper {
+
+		private String message;
+
+		public RedirectMessageExternalContext(ExternalContext wrapped, String message) {
+			super(wrapped);
+			this.message = message;
+		}
+
+		@Override
+		public void redirect(String url) throws IOException {
+			addFlashGlobalWarn(message);
+			super.redirect(url);
+		}
+	}
+
+	// Getters/setters ------------------------------------------------------------------------------------------------
+
 	/**
 	 * Returns <code>true</code> if the <code>immediate="true"</code> attribute is <strong>not</strong> set, otherwise
 	 * delegate to super, hereby maintaining the original behavior of <code>immediate="true"</code>.
@@ -83,4 +166,22 @@ public boolean isRendered() {
 		return !isImmediate() || super.isRendered();
 	}
 
+	/**
+	 * Returns the global flash warning message to be shown in the redirected page.
+	 * @return The global flash warning message to be shown in the redirected page.
+	 * @since 3.2
+	 */
+	public String getMessage() {
+		return state.get(PropertyKeys.message);
+	}
+
+	/**
+	 * Sets the global flash warning message to be shown in the redirected page.
+	 * @param message The global flash warning message to be shown in the redirected page.
+	 * @since 3.2
+	 */
+	public void setMessage(String message) {
+		state.put(PropertyKeys.message, message);
+	}
+
 }

src/main/resources/META-INF/omnifaces-ui.taglib.xml

@@ -2696,6 +2696,15 @@ If <code>#{bean.bar}</code> is any other value, then it will appear in the hash
 					<p>
 					Only when you set <code>immediate="true"</code>, then it will behave the same as the standard
 					<code>&lt;f:viewAction&gt;</code>.
+					<h3>Messaging</h3>
+					<p>
+					You can use the <code>message</code> attribute to add a global flash warning message.
+					<pre>
+					&lt;o:viewAction ... message="Please use a valid link from within the site" /&gt;
+					</pre>
+					<p>
+					Note that the message will only be shown when the redirect has actually taken place. The support was added in
+					OmniFaces 3.2.
  				]]>
 		</description>
 		<tag-name>viewAction</tag-name>
@@ -2777,6 +2786,16 @@ If <code>#{bean.bar}</code> is any other value, then it will appear in the hash
 			<required>false</required>
 			<type>boolean</type>
 		</attribute>
+		<attribute>
+			<description>
+				<![CDATA[
+					The message to send along with the redirect, if any.
+				]]>
+			</description>
+			<name>message</name>
+			<required>false</required>
+			<type>java.lang.String</type>
+		</attribute>
 	</tag>
 
 	<tag>