From Documentation

Jump to: navigation, search




  • Author
    Timothy Clare, Potix Corporation
  • Date
    May 26, 2015
  • Version
    ZK 8.0.0 RC


Contents

Introduction

The ZK team is proud to announce the release of ZK 8 RC!

ZK 8's main focus is on providing developers even more powerful tools, allowing faster and more accurate development of Java Web Applications. We are proud to announce an extensive improvement to EL, which is now supporting EL3, major MVVM enhancements and many more changes.

To understand why you need ZK 8, and how it helps you to stay true to your Java roots, but also effortlessly keep up with the ever-evolving world of front-end technologies, read ZK 8 Philosophy

Download and Demo




Support Expression Language 3 (EL3)

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

Introducing the new generation expression language of Java EE 7 – Expression Language 3 (EL 3). In ZK 8 we can now do more complicated and more powerful things with this newer expression language. There are many new features in EL 3 such as new operators, lambda expressions and collection operations. For more information on EL3 please take a look at the specification, JSR-341.

Please note that EL3 and all its features (including Lambda expressions) work for JDK 5 and above.

Lambda Expressions

Each converter is implemented with the capability to interpret lambda expressions defined in zul. The following shows an example of a textbox who's value and onOK command are both driven by lambdas.

<textbox value="@load((x -> (x * 100) / 2.54)(vm.value))" 
    onOK="@command('click', key=((x -> (x * 2.54) / 100)(self.value)))" />

The syntax used is same as the ones in Java SE 8 and behaves like an anonymous function which is discarded after evaluation. We can name a lambda and evaluate indirectly.

Take the lambda expression (x -> (x * 100) / 2.54) for example. In this case, it will create an anonymous function which takes a value, multiplies it by 100 and divides the result by 2.54. This function is then applied to vm.value, where vm stands for our viewmodel.

To simplify this, let's write some psuedo code for demonstration purposes.

myFunction = x -> (x * 100) / 2.54 //assign a lambda to myFunction temporarily
myFunction(vm.value) //execute myFunction passing vm.value as the parameter

While the above is just pseudo code to better help you understand the functionality, it does demonstrate naming of lambdas, which is also possible. The following section outlines the steps to doing this with two new operators.

New Operators

String Concatenation

String concatenation has been introduced to make it easy to construct strings within EL expressions. The following code snippet demonstrates how to do so.

<label value="@load(('Hi, ' += vm.firstname += ' ' += vm.lastname))" />

Assignment and Semicolons

Both assignment and semicolon operators are now implemented. Below shows an example of both being used.

<label value="@load((incr = x -> x + 1; incr(5)))" />

The assignment operator in this instance assigns a lambda function to incr which takes x, increments by 1 and then returns it.

incr = x -> x + 1

By using the ';' operator, the left hand side is evaluated first; thus creating a lambda function incr, as previously discussed. Then, it evaluates and returns the right hand side. So in the following case:

<label value="@load((incr = x -> x + 1; incr(5)))" />

The value assigned to the label would be 6, as the lambda function is first evaluated and assigned to incr, then the incr(5) call is evaluated leading to a return value of 6.


Collection Operations

In ZK 8 it is now possible to use collection chain operations directly. In the example below we turn vm.names into stream() and create a pipeline of commands.

<listbox model="@load((vm.names.stream()
                               .filter(x -> x.contains(vm.filter))
                               .toList()))">

In addition to pipelines ZK 8's EL 3 supports easy collection construction using brackets ([ ]). The following example demonstrates this:

<label value="@load(([1, 2, 3, 4].stream().sum()))" />


Static Field and Method Access

A static field or static method of a Java class can be accessed with the syntax Classname.Field, such as

	
<label value="@load((Math.sqrt(16)))" />

Please note that java.lang.* is imported by default.

Major MVVM Enhancements

Performance Increase

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png


ZK 8 ensures increases in MVVM binding performance, with both a memory consumption decrease and a response time increase. Below is the graph outlining these performance changes.

Memory Improvements

ZK 8.0.0 RC requires much less memory than ZK 7.0.5 EE, which means you could boost your application by simply upgrading. The graph plots the number of users against the memory used, where the lower the better.

Memory-improvement.png

Response Improvements

ZK 8.0.0 RC MVVM also responds quicker than ZK 7.0.5 EE. The graph below plots the number of users against the response time, where the lower the response time the better.

Response-improvement.png


Recreating the tests

If you would like to recreate the tests above in your environment, you can use the following code:

Java code

package org.zkoss.test;
 
import java.util.Collections;
import java.util.List;
 
public class ForEachVM {
	private List<Integer> array = Collections.nCopies(30, 30);
	public void setArray(List<Integer> array) {}
	public List<Integer> getArray() {
		return array;
	}
}

ZUL

<zk xmlns:x="xhtml">
	<div id="bind" apply="org.zkoss.bind.BindComposer"
		viewModel="@id('vm') @init('org.zkoss.test.ForEachVM')">
		<div style="display:none" id="host">
			<div children="@load(vm.array)">
				<template name="children">
				<div children="@load(vm.array)">
					<template name="children">
					Test Label
					</template>
				</div>
				</template>
			</div>
		</div>
	</div>
</zk>

SmartNotifyChange

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


ZK 8 brings about a change to the notify system. Users typically rely on @NotifyChange; however, ZK 8 has a better way, @SmartNotifyChange. Essentially the usage is exactly the same as @NotifyChange, except it will only notify the binder when a value has been changed, unlike @NotifyChange. Thus, it is able to achieve optimal performance.

The following shows some example code:

public class OrderVM {

    //other code...

    //action command
    @SmartNotifyChange({"selected","orders","messages"})
    @Command
    public void newOrder(){
        Order order = new Order();
        getOrders().add(order); //add new order to order list
        selected = order;//select the new one
    }
}

For more information, please consult the ZK MVVM Reference and the new form binding blog.

MVVM support at the client

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


After listening to feedback, the ZK team has introduced functionality in ZK 8 which allows developers to access ViewModel properties at the client. The following couple of code snippets demonstrate how to use this functionality.

Publishing a command using native components or direct invocation

<xhtml:button n:onClick="@command('doClick', {key:value, key1:value1})"/>
wgt.$binder().command('doClick', args);

Subscribing to commands

wgt.$binder().after('commandName', callbackFuncation);

For more information, please take a look at the ZK 8 Series Smalltalk.

BindingParam annotation supports converting from JSON to POJO automatically

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png


ZK 8 now supports the ability to convert JSON sent to ZK into objects at the server automatically. Consider this example.

zkbind.$(someone).command('dataChange', {data:{title: "myData"}});

The above code will send JSON data to the command function "dataChange"; this can be automatically converted into an appropriate object using the BindingParam.

public static class DataObject {
	private String title;
	public void setTitle(String title) {
		this.title = title;
	}
	public String getTitle() {return title;}
}

@Command
public void dataChange(@BindingParam("data") DataObject data) {
	// do something here.
}

For more information, please visit ZK Configuration Reference.

Children binding supports list model

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


In ZK 8, children binding supports a ListModel! This means you can separate the View and Model by implementing ListModel, which is used to provide data. Additionally, when you add/update/remove the data in the model, the corresponding components in children binding will be re-rendered at the same time.

When using List in children binding, to update data you have to use @NotifyChange to notify the binder any property changes, and the whole rendered components in children binding will be re-rendered at the same time.

The following example outlines the usage.

<vlayout children="@load(vm.model)">
  <template name="children">
  ...
  </template>
</vlayout>
private ListModelList model = new ListModelList();
...

@Command
public void add_model() {
  Product newProduct = new Product(++count, "Microwave oven", 999);
  model.add(newProduct);
}

For more information, please take a look at our blog series on ZK 8 data binding.

FormattedTimeConverter introduced

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


ZK 8 introduces a new converter named formattedTime. This makes it extremely easy to output a specific time using a specified format. The following shows an example:

<label value="@load(item.time) @converter('formattedTime', format='hhmmss')"/>

For more information, please refer to refer to our ZK MVVM Reference.

New components & enhancements

Lightweight rich editor

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png

ZK 8 introduces a brand new lightweight component called Tbeditor, representing the JavaScript component Trumbowyg. Tbeditor is a rich WYSIWYG text editor.

The following is an example of how to use Tbeditor in your application.

Zkcompref tbeditor.png

<tbeditor id="tb" value="this is a demo for &lt;b&gt;trumbowy&lt;/b&gt; editor!!" />

For more information please consult the ZK Component Reference.

Timepicker Component

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png

ZK 8 introduces a new component to handle times. The component also has a lot of functionality such as minimum & maximum times along with formatting.

ZKCompRef Timepicker.png


 <window title="Simple" width="300px" border="normal">
     <timebox id="tb0"/>
 </window>

For more information please consult the ZK Component Reference.

Scrollview component

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png


The Scrollview component, first introduced in ZK 6.5 with mobile and tablet compatibility, is now also available on desktop. With the amazing infinite scrolling feature.

For example,

<zscript><![CDATA[
public void append(Scrollview sv, int pos, boolean outBound) {
	if (outBound && pos > 0) {
		Window w = new Window("window end", "normal", false);
		sv.appendChild(w);
	}
}
]]></zscript>
<scrollview id="sv" onScroll="append(self, event.pos, event.outOfBound)" orient="horizontal">
	<window title="window1" border="normal">
            This is Window 1
        </window>
</scrollview>

With that, users can scroll down endlessly.

Just like in the 6.5 version, this component also provides two events.

  • onScroll
  • onScrolling

The only difference is that in ZK 8.0, the onScroll event will be triggered when users scroll all the way to the top or to the end of the page. The onScrolling event remains the same as before.


For more information please consult the ZK Component Reference.

Rowlayout

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png

ZK 8 introduces a new, powerful layout component named rowlayout which allows developers to place components inside a grid. This allows for flexible and simple layouts. The following diagram illustrates the rowlayout/rowchildren components and their various configurable parameters.

ZKComRef Rowlayout.PNG

Using rowlayout component is simple. First, use rowlayout to divide the horizontal space of its parent container into a number of columns. You can also optionally specify the column/spacing ratio. The default number of columns is 12, and the default column/spacing ratio is 1/3, which means column is 3 times wider than the spacing between columns. Spacing could be given as a ratio, a percentage or a floating-point number.

A sample usage is demonstrated below.

<rowlayout ncols="12" spacing="1/3">
	<rowchildren colspan="3" offset="2">
	</rowchildren>
</rowlayout>

For more information please consult the ZK Component Reference.

Shadow Elements

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ee.png

ZK 8 introduces a new concept called Shadow Element.

In simple terms shadow elements help application developers to compose an html layout with some dynamic data. They are basically templates, however, with shadow elements it helps the application to manage templates and their implementation that are outside of the component tree. Thus a shadow element is not visible to users but is handled by ZK.

A web designer can pre-define a template based on HTML syntax for application developers to use.

For example,

<div>
    <if test="${user.editable}">
        User Name: <textbox value="${user.name}"/>
        <forEach items="${user.phones}" var="phone">
            <label value="${phone.number}"/>
        </forEach>
    </if>
</div>

Shadow Diagram.PNG

As shown in the diagram above, the tree is separated into two parts - Logical Tree and Composed Tree.

  • Logical Tree is created by ZK page parser to construct a page definition tree and then instantiate it into a "Composed Tree".
  • Composed Tree is also separated into two parts, one is the component tree (green area) which is the same as before, and the other is the new concept (red area) shadow tree, which is not visible for application developers but component developers.

The shadow tree in the example above with EL expression won't be alive once the output is rendered to the client. This is because shadow elements are not applied with dynamic data such as @load expressions, so there is no reason to store them in the server side to burden the memory consumption.


Example

To give an example of the power available, the following demo outlines an application using 3 dataviews (grid, list and tree) using the same dataset and codebase.



To fully understand the power of shadow components, please refer to the ZK 8 Series Smalltalk.

Custom data attribute handlers are now possible

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


It is possible to define custom data-handlers for client attributes which gives extra flexibility to developers looking to integrate and use 3rd party libraries.

For example, the following demonstrates a data-handler for jQuery's mask functionality:


Zul File:

<textbox xmlns:ca="client/attribute" ca:data-mask="00:00:00" onChange='Clients.log(self.value)'/>

zk.xml:

<client-config>	
	<data-handler>
		<name>mask</name><!-- the attribute name, i.e. data-mask -->
		<depends>http://igorescobar.github.io/jQuery-Mask-Plugin/js/jquery.mask.min.js</depends>
		<script>
		function (wgt, dataValue) {
			jq(wgt.$n()).mask(dataValue);

			// unformat after onChange event.
			wgt.listen({onChange: function (event) {
				event.data.value = jq(this.$n()).cleanVal();
			}});
		}
		</script>
	</data-handler>
</client-config>

For more information, please refer to the ZK ZUML Reference.

Font Awesome upgrade

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


Font awesome has been upgraded to version 4.3, introducing over 40 new icons. For more details please check the font-awesome website.

Introduced Danish language support

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


Thanks to our contributor Flemming Birch-Rasmussen ZK 8 now provides support for the Danish language.

Other changes

ZHTML component's src attribute supports encoded url in ZUL

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

ZK 8's ZHTML components now support encoded urls, this makes it much easier to specify images and other urls on the src attribute.

For example:

<x:img xmlns:x="xhtml" src="~./img/spacer.gif" xmlns:c="client" c:onBind='zk.log(this.$n().src)'/>

For more information please refer to the ZK Component Reference.

ZHTML supports dynamic data binding

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png


The textContent attribute now supports dynamic databinding, meaning it is now possible to use MVVM based commands for a textContent attribute. For example:

<label textContent="@load(each.author.name)"
	sclass="author-name z-label" />

Simplified thrown exceptions

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

Exceptions were thrown as UIExceptions and when including templates or similar procedures the resulting stacktrace was exceptionally hard to follow. This also make it difficult to create meaningful error pages for application.

With the advent of ZK 8, exceptions are no longer wrapped with UIException; they will throw a RuntimeException.

Multiple custom error messages supported for multiple constraints

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

Previously when defining constraints only the last constraint could have a separate error message. This has now been rectified and every constraint can have its own custom error message.

For example:

<datebox constraint="no empty: please select a date, no future: now or never" />

For more information please refer to ZK's Component Reference.

Datebox calendar now contains a today button

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

Since ZK 8 the Datebox calendar now contains a button which can easily reset the date to today. The button takes on the form of the current date.

ZKComRef Datebox Link Of Today.PNG

Embedded types now allowed

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

When parsing a page, sometimes an error would occur when HTML was embedded in a ZHTML page. This has now been fixed and the ability to use different parsers depend on the syntax allowed in the page.

For example, here we have HTML embedded inside ZHTML:

<html>
	<head>
		 <!--[if lte IE 9]>
			<link rel="stylesheet" href="../assets/css/test.min.css" />
		<![endif]-->
	</head>
<body>
<u:window xmlns:u="zul" title="test" id="mainWindow" apply="org.zkoss.bind.BindComposer"
	viewModel="@id('vm') @init('test.MyVM')" height="100%" width="100%">
	&copy Test
</u:window>
</body>
</html>

ForeachStatus is consistent with JSTL's varStatus properties

  • Available for ZK:
  • http://www.zkoss.org/product/zkhttp://www.zkoss.org/whyzk/zkeeVersion ce-pe-ee.png

ZK's ForEachStatus now has the same properties as varStatus, so it is more intuitive for developers to use what they are used to as is.

<zk xmlns:n="native">
	<n:h4>1. Test case: forEach="one, two, three, four"</n:h4>
	<zscript>
	items = Arrays.asList(new Object[] { "one", "two", "three", "four" });
</zscript>
	<div style="border:1px solid blue">
		<div forEach="${items}">
			${each} Index: ${forEachStatus.index} Count:
			${forEachStatus.count} First: ${forEachStatus.first} Last:
			${forEachStatus.last}
		</div>
	</div>
	Result:
	<div style="border:1px solid red;color:blue">
		<div>one Index: 0 Count: 1 First: true Last: false</div>
		<div>two Index: 1 Count: 2 First: false Last: false</div>
		<div>three Index: 2 Count: 3 First: false Last: false</div>
		<div>four Index: 3 Count: 4 First: false Last: true</div>
	</div>
	<n:h4>2. Test case: forEach="one, two, three, four" forEachStep="3"</n:h4>
	<div style="border:1px solid blue">
		<div forEach="${items}" forEachStep="3">
			${each} Index: ${forEachStatus.index} Count:
			${forEachStatus.count} First: ${forEachStatus.first} Last:
			${forEachStatus.last}
		</div>
	</div>
	Result:
	<div style="border:1px solid red;color:blue">
		<div>one Index: 0 Count: 1 First: true Last: false</div>
		<div>four Index: 3 Count: 2 First: false Last: true</div>
	</div>
	<n:h4>3. Test case: forEach="one, two, three, four" forEachBegin="1" forEachStep="3"
	</n:h4>
	<div style="border:1px solid blue">
		<div forEach="${items}" forEachBegin="1" forEachStep="3">
			${each} Index: ${forEachStatus.index} Count:
			${forEachStatus.count} First: ${forEachStatus.first} Last:
			${forEachStatus.last}
		</div>
	</div>
	Result:
	<div style="border:1px solid red;color:blue">
		<div>two Index: 1 Count: 1 First: true Last: true</div>
	</div>
</zk>


Comments



Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.