Wicket Ajax suspension

ajax-suspension.patch

diff --git a/wicket-core/src/main/java/org/apache/wicket/ajax/res/js/wicket-ajax-jquery.js b/wicket-core/src/main/java/org/apache/wicket/ajax/res/js/wicket-ajax-jquery.js
index 70dd69d..bb952bc 100644
--- a/wicket-core/src/main/java/org/apache/wicket/ajax/res/js/wicket-ajax-jquery.js
+++ b/wicket-core/src/main/java/org/apache/wicket/ajax/res/js/wicket-ajax-jquery.js
@@ -933,16 +933,6 @@
 		 */
 		processEvaluation: function (context, node) {
 
-			// used to match evaluation scripts which manually call FunctionsExecuter's notify() when ready
-			var scriptWithIdentifierR = new RegExp("\\(function\\(\\)\\{([a-zA-Z_]\\w*)\\|((.|\\n)*)?\\}\\)\\(\\);$");
-
-			/**
-			 * A regex used to split the text in (priority-)evaluate elements in the Ajax response
-			 * when there are scripts which require manual call of 'FunctionExecutor#notify()'
-			 * @type {RegExp}
-			 */
-			var scriptSplitterR = new RegExp("\\(function\\(\\)\\{[\\s\\S]*?}\\)\\(\\);", 'gi');
-
 			// get the javascript body
 			var text = Wicket.DOM.text(node);
 
@@ -950,61 +940,54 @@
 			var steps = context.steps;
 			var log = Wicket.Log;
 
-			var evaluateWithManualNotify = function (parameters, body) {
-				return function(notify) {
-					var toExecute = "(function(" + parameters + ") {" + body + "})";
-
-					try {
-						// do the evaluation in global scope
-						var f = window.eval(toExecute);
-						f(notify);
-					} catch (exception) {
-						log.error("Wicket.Ajax.Call.processEvaluation: Exception evaluating javascript: %s", text, exception);
-					}
-					return FunctionsExecuter.ASYNC;
-				};
-			};
-
 			var evaluate = function (script) {
 				return function(notify) {
-					// just evaluate the javascript
+					// start with no suspension
+					Wicket.Ajax._suspended = 0;
+					Wicket.Ajax.suspend = function() {
+						// keep track of suspensions
+						Wicket.Ajax._suspended++;
+						
+						var released = false;
+						
+						return function() {
+							// relase only once
+							if (released == false) {
+								released = true;
+								
+								// keep track of suspensions
+								Wicket.Ajax._suspended--;
+								
+								if (Wicket.Ajax._suspended == 0) {
+									// last suspension released
+									notify();
+								}
+							}
+						}
+					};
+					
+					// evaluate the javascript
 					try {
 						// do the evaluation in global scope
 						window.eval(script);
 					} catch (exception) {
 						log.error("Ajax.Call.processEvaluation: Exception evaluating javascript: %s", text, exception);
 					}
-					// continue to next step
-					return FunctionsExecuter.DONE;
+					
+					if (Wicket.Ajax._suspended) {
+						// suspended
+						return FunctionsExecuter.ASYNC;
+					} else {
+						// no suspension
+						Wicket.Ajax._suspended = undefined;
+						Wicket.Ajax.suspend = undefined;
+						
+						// continue to next step
+						return FunctionsExecuter.DONE;
+					}
 				};
 			};
-
-			// test if the javascript is in form of identifier|code
-			// if it is, we allow for letting the javascript decide when the rest of processing will continue
-			// by invoking identifier();. This allows usage of some asynchronous/deferred logic before the next script
-			// See WICKET-5039
-			if (scriptWithIdentifierR.test(text)) {
-				var scripts = [];
-				var scr;
-				while ( (scr = scriptSplitterR.exec(text) ) !== null ) {
-					scripts.push(scr[0]);
-				}
-
-				for (var s = 0; s < scripts.length; s++) {
-					var script = scripts[s];
-					if (script) {
-						var scriptWithIdentifier = script.match(scriptWithIdentifierR);
-						if (scriptWithIdentifier) {
-							steps.push(evaluateWithManualNotify(scriptWithIdentifier[1], scriptWithIdentifier[2]));
-						}
-						else {
-							steps.push(evaluate(script));
-						}
-					}
-				}
-			} else {
-				steps.push(evaluate(text));
-			}
+			steps.push(evaluate(text));
 		},
 
 		// Adds a closure that processes a header contribution
diff --git a/wicket-core/src/main/java/org/apache/wicket/core/request/handler/IPartialPageRequestHandler.java b/wicket-core/src/main/java/org/apache/wicket/core/request/handler/IPartialPageRequestHandler.java
index da126a2..e7a2a52 100644
--- a/wicket-core/src/main/java/org/apache/wicket/core/request/handler/IPartialPageRequestHandler.java
+++ b/wicket-core/src/main/java/org/apache/wicket/core/request/handler/IPartialPageRequestHandler.java
@@ -64,15 +64,22 @@
 	void addChildren(MarkupContainer parent, Class<?> childCriteria);
 
 	/**
-	 * Adds javascript that will be evaluated on the client side after components are replaced
-	 *
-	 * <p>If the javascript needs to do something asynchronously (i.e. needs to use window.setTimeout(), for example
-	 * to do animations) then the following special syntax may be used: <code>someFunctionName|myJsLogic(someFunctionName);</code>.
-	 * Wicket will transform it to: <code>function(someFunctionName){myJsLogic(someFunctionName);}</code> and your code
-	 * is responsible to execute <em>someFunctionName()</em> when the asynchronous task is finished. Once <em>someFunctionName</em>
-	 * is executed the next appended script will be executed. <strong>Important</strong>: it is highly recommended to
-	 * execute your code in try/finally to make sure <em>someFunctionName</em> is executed even an error happens in
-	 * your code, otherwise all following scripts wont be executed.</p>
+	 * Adds JavaScript that will be evaluated on the client side after components are replaced
+	 * <p>
+	 * If the JavaScript needs to do something asynchronously (i.e. needs to use window.setTimeout(), for example to do animations)
+	 * then the global method <code>Wicket.Ajax.suspend()</code> may be used, e.g.:
+	 * <pre>
+	 * target.prependJavaScript("jQuery('#id').fadeOut(1000, Wicket.Ajax.suspend());");
+	 * target.appendJavaScript("jQuery('#id').hide().fadeIn(1000, Wicket.Ajax.suspend());");
+	 * </pre>
+	 * <code>suspend()</code> returns a JavaScript function which your code is responsible to invoke when the
+	 * asynchronous task has finished (in the example above done automatically by jQuery fading methods).
+	 * Once this is done the next appended script will be executed.
+	 * <p>
+	 * <strong>Important</strong>: it is highly recommended to execute your code in try/finally to
+	 * make sure the suspension is released even an error happens in your code, otherwise all
+	 * following scripts wont be executed.
+	 * </p>
 	 *
 	 * @param javascript
 	 */
diff --git a/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.html b/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.html
index 241c86e..ea078c7 100644
--- a/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.html
+++ b/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.html
@@ -21,7 +21,12 @@
 counter 2: <span wicket:id="c2"></span>
 <br/>
 <br/>
-<a href="#" wicket:id="c1-link">counter1++ and shake</a>&#160;&#160;<a href="#" wicket:id="c2-link">counter2++ and highlight</a>
+counter 3: <span wicket:id="c3"></span>
+<br/>
+<br/>
+<a href="#" wicket:id="c1-link">counter1++ and shake</a>&#160;&#160;
+<a href="#" wicket:id="c2-link">counter2++ and highlight</a>&#160;&#160;
+<a href="#" wicket:id="c3-link">counter3++ and fade</a>
 </div>
 </wicket:extend>
 </html>
\ No newline at end of file
diff --git a/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.java b/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.java
index e286584..4b48677 100644
--- a/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.java
+++ b/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/EffectsPage.java
@@ -36,40 +36,7 @@
 {
 	private int counter1 = 0;
 	private int counter2 = 0;
-
-	/**
-	 * @return Value of counter1
-	 */
-	public int getCounter1()
-	{
-		return counter1;
-	}
-
-	/**
-	 * @param counter1
-	 *            New value for counter1
-	 */
-	public void setCounter1(int counter1)
-	{
-		this.counter1 = counter1;
-	}
-
-	/**
-	 * @return Value for counter2
-	 */
-	public int getCounter2()
-	{
-		return counter2;
-	}
-
-	/**
-	 * @param counter2
-	 *            New value for counter2
-	 */
-	public void setCounter2(int counter2)
-	{
-		this.counter2 = counter2;
-	}
+	private int counter3 = 0;
 
 	/**
 	 * Constructor
@@ -84,6 +51,10 @@
 		c2.setOutputMarkupId(true);
 		add(c2);
 
+		final Label c3 = new Label("c3", new PropertyModel<>(this, "counter3"));
+		c3.setOutputMarkupId(true);
+		add(c3);
+
 		add(new AjaxLink<Void>("c1-link")
 		{
 			@Override
@@ -91,8 +62,7 @@
 			{
 				counter1++;
 				target.add(c1);
-				target.appendJavaScript(String.format("jQuery('#%s').effect('shake');",
-					c1.getMarkupId()));
+				target.appendJavaScript(String.format("jQuery('#%s').effect('shake');", c1.getMarkupId()));
 			}
 
 			@Override
@@ -112,8 +82,29 @@
 				counter2++;
 				targetOptional.ifPresent(target -> {
 					target.add(c2);
-					target.appendJavaScript(String.format("jQuery('#%s').effect('highlight');",
-							c2.getMarkupId()));
+					target.appendJavaScript(String.format("jQuery('#%s').effect('highlight');", c2.getMarkupId()));
+				});
+			}
+
+			@Override
+			protected void updateAjaxAttributes(AjaxRequestAttributes attributes)
+			{
+				attributes.setChannel(new AjaxChannel("effects", Type.DROP));
+
+				super.updateAjaxAttributes(attributes);
+			}
+		});
+		
+		add(new AjaxFallbackLink<Void>("c3-link")
+		{
+			@Override
+			public void onClick(Optional<AjaxRequestTarget> targetOptional)
+			{
+				counter3++;
+				targetOptional.ifPresent(target -> {
+					target.prependJavaScript(String.format("jQuery('#%s').fadeOut(1000, Wicket.Ajax.suspend());",c3.getMarkupId()));
+					target.add(c3);
+					target.appendJavaScript(String.format("jQuery('#%s').hide().fadeIn(1000, Wicket.Ajax.suspend());", c3.getMarkupId()));
 				});
 			}