DWR Autosuggetion

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4. Server side Java objects:...................................................................................................................... 7

create Java class, which will be called by the DWR javascript: ............................................................... 7

4.1. SearchAction.java: ....................................................................................................................... 7

4.2. SearchUtil.java: ............................................................................................................................ 8

4.3. DatabaseUtil.java ........................................................................................................................ 9

4.4. CommonConstant.java .............................................................................................................. 10

5. Index.html: ........................................................................................................................................ 10

6.Figure: ..................................................................................................................................................... 10


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1.IntroductionThe browser side JavaScript objects are implemented by the DWR JavaScript code. This code

communicates with the servlet at the backend using asynchronous XMLHttpRequest support of

the browser.

Operations performed by DWR during remoting include:

DWR runtime processes a dwr.xml file to determine the objects that needs to be remoted DWR uses Java reflection to find out about the available fields and methods of the

server-side object

DWR generates JavaScript code that creates equivalent JavaScript objects within thebrowser

All methods in the JavaScript object are invoked remotely and handled by the DWRservlet

Methods that return values are handled by converter within DWR.DWR consists of two main parts:

A Java Servlet running on the server that processes requests and sends responses back tothe browser.

JavaScript running in the browser that sends requests and can dynamically update thewebpage.

which consists of:

1. A servlet (uk.ltd.getahead.dwr.DWRServlet)2. A set of JavaScript libraries (util.js and engine.js)

2.JavaScript files that must be included in your application for DWR:2.1. JCustomer.js:

complete path is //dwr/interface/.js.

in my application the path is /fas.war/dwr/interface/JCustomer.js and one more javascript file/fas.war/dwr/interface/searchDwr.js

searchDwr.js

var nameRegEx = /^([a-zA-Z\-\/&_]){1,50}$/;

functionpopulateSearchFied(obj){


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var textfieldValue = obj.value;

if(nameRegEx.test(textfieldValue) ==false){removeList();

return false;}

JCustomer.getSearchResultAction(textfieldValue,searchCallback);

removeList();var v=document.getElementById("customerName").value;

}

function searchCallback(msg) {if (msg.length > 0) {document.getElementById("suggestions").style.display = "block";var sList = document.getElementById("suggestionsList");

var ul = document.createElement('ul');

for (var i = 0; i < msg.length; i++){var li = document.createElement('li');li.innerHTML = msg[i];li.onclick = bindFunction(msg[i]);ul.appendChild(li);}

sList.appendChild(ul);}

}

functionbindFunction(txt) {return function () {fillTextField(txt);};

}

function fillTextField(txt) {document.getElementById("customerName").value = txt;document.getElementById("suggestions").style.display = "none";

removeList();

}

function removeList() {var sList = document.getElementById("suggestionsList");var children = sList.childNodes;for (var i = 0; i < children.length; i++) {

sList.removeChild(children[i]);}

}

JCustomer.jsfunction JCustomer () {}


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Setting debug parameter to true allows you to troubleshoot DWR readily to determine if things

are working alright.

3.4. A dwr.xml file,placed also into the WEB-INF directory:Which contains information for DWR. This file specifies the Java classes that should be remoted to

JavaScript. This file contains:

As you can see in above code, i have added the creator attribute which will tell the dwr engine to create

the javascript object named JCustomer, using which we can call the server side methods.

The above configuration tells DWR that:

1. com.fas.dwr.action.SearchAction should be remoted to JCustomer JavaScript object2. JavaScript code can create instances remotely which return values and arguments oftype JCustomer will be converted

What exactly do the JCustomer objects looks like? Next we explore the server side Java

objects.


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4.Server side Java objects:create Java class, which will be called by the DWR javascript:

4.1. SearchAction.java:Helper method and fields of the com.fas.dwr.action. SearchAction class

getSearchResultAction(StringfieldValue)

A method to obtain all of the customer names from the database

which contains character like searchKey. This method returns

an string array of Customer objects. On the server-side, this is

an array of Customer Java objects. DWR will convert them toan array of JCustomer JavaScript objects on the browser side.

SearchAction.java

package com.fas.dwr.action;

import com.fas.dwr.utils.SearchUtil;

publicclass SearchAction{

public String[] getSearchResultAction(String fieldValue){

String dataList[] = null;SearchUtil searchUtil = null;try{

searchUtil = new SearchUtil();dataList = searchUtil.fetchResult(fieldValue.trim());

}catch(NullPointerException nullExp){}

return dataList;}

}


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4.2. SearchUtil.java:Helper method and fields of the com.fas.dwr.utils. SearchUtil class

fetchResult (StringsearchKey)

This method takes a string argument searchKey and returnsstring array

OST_STOCK.CUSTOMER_NAME OST_STOCK is a table name and CUSTOMER_NAME is acoloumn name in database.

package com.fas.dwr.utils;

import java.util.List;

import com.broadvision.data.client.Content;import com.broadvision.data.common.TableData;import com.broadvision.data.sql.SQLCondition;import com.broadvision.data.sql.SQLExpression;import com.broadvision.data.sql.SQLOperator;import com.fas.common.utils.CommonConstants;

publicclass SearchUtil{

public String[] fetchResult(String searchKey){

List returnParamter = null;

DatabaseUtil dataTranscation = null;SQLCondition sqlCondition = null;SQLExpression sqlExpression = null;String []htmlBuilder = null;

try{

sqlExpression = new SQLExpression("OST_STOCK.CUSTOMER_NAME ");

sqlCondition = new SQLCondition(sqlExpression,SQLOperator.OP_LIKE,newSQLExpression(("'%"+searchKey+"%'")));dataTranscation = new DatabaseUtil();returnParamter =dataTranscation.getContentList(CommonConstants.BV_OST_STOCK_CONTENT_TYPE_ID,

sqlCondition);if(null != returnParamter){

htmlBuilder = new String[returnParamter.size()];Content content = null;for(int i=0;i


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}

}catch(Exception ee){

}

return htmlBuilder;}

4.3. DatabaseUtil.javaHelper method and fields of the com.fas.dwr.utils. DatabaseUtil class:

DatabaseUtil A constructor which contains a static block .getContentList Returns a List based on query condition.

this util class obtain customer names from the database which contains keyword like searchKey.

package com.fas.dwr.utils;

import java.util.ArrayList;

import java.util.List;

import com.broadvision.data.client.DataManager;

import com.fas.common.utils.CommonConstants;

public class DatabaseUtil{

private static DataManager dataManager=null;

static{

try{

dataManager=new DataManager();

}catch(Exception e){

System.out.println(">>>>> Data Base initialization failed while init data manager");

}

}public List getContentList(int contentId,SQLCondition condition){

List contentList = null;try{

contentList = new ArrayList();contentList = dataManager.getContentsByCondition(contentId,

CommonConstants.FAS_SERVICE_ID, condition, true);

}catch(Exception ee){

}return contentList;

}

}


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4.4. CommonConstant.javapackage com.fas.common.utils;

publicclass CommonConstants {

publicstaticfinalintBV_OST_STOCK_CONTENT_TYPE_ID=1002;

publicstaticfinalintFAS_SERVICE_ID=92;

}

5.Index.html:create index.html using below code:

Search

Name:

6.Figure:

DWR makes Java objects appear as remote JavaScript objects:

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DWR Autosuggetion