Validating Form When User Clicks Submit with ZK Framework

<textbox 
     value="@load(vm.someAttribute) @save(vm.someAttribute, before='save')" 
     constraint="no empty" .../>

<button label="Submit" onClick="@command('save')"/>

Zk form validation before button click.

Validation.zul

<zk xmlns:x="xhtml" xmlns:zk="zk">

      <window width="100%" height="100%"

            apply="org.zkoss.bind.BindComposer"

            viewModel="@id('vm') @init('test.test.Validation')"

            form="@id('fx') @load(vm) @save(vm,before='doSave')">

            <vlayout sclass="vertical-scroll" vflex="1">

                  <toolbar id="listToolbarProcess" sclass="vista"

                        height="20px" align="start">

                        <toolbarbutton label="Save"

                              onClick="@command('doSave')" />

                  </toolbar>

                  <intbox id="priority" maxlength="3" constraint="no empty"

                        value="@bind(fx.value)" />

                  <datebox value="@bind(fx.date)"></datebox>

            </vlayout>

      </window>

</zk>

Validation.java

package test.test;

import java.sql.Timestamp;

import org.zkoss.bind.annotation.AfterCompose;

import org.zkoss.bind.annotation.Command;

import org.zkoss.bind.annotation.ContextParam;

import org.zkoss.bind.annotation.ContextType;

import org.zkoss.zk.ui.Component;

public class Validation {

                /**

                 * @author Himanshu

                 */

                @AfterCompose

                public void afterCompose(@ContextParam(ContextType.VIEW) Component view) {

                }

                @Command

                public void doSave() {

                                System.out.println(" value =" + str);

                                System.out.println(" Date Value =" + date);

                }

                boolean check;

                public boolean isCheck() {

                                return check;

                }

                public void setCheck(boolean check) {

                                this.check = check;

                }

                Integer value;

                public Integer getValue() {

                                return value;

                }

                public void setValue(Integer value) {

                                this.value = value;

                }

                String str;

                public String getStr() {

                                return str;

                }

                public void setStr(String str) {

                                this.str = str;

                }

                Timestamp date;

                public Timestamp getDate() {

                                return date;

                }

                public void setDate(Timestamp date) {

                                this.date = date;

                }

}