AdvancED Flex 4

CHAPTER 7

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Integration Based on HTTP Requests

HTTP calls are simpler than web services, so let’s start with them. Begin by creating a really simple Java

application that uses a few simple classes and JSP to generate XML content. We’ll consume this XML

content from within a Flex application.

This elementary Java application produces a collection of all-time top ten NBA scorers. Each entry in the

list includes the scorer’s first name and last name, the total score, and his position in the top ten list. Each

entry maps to a simple JavaBean class, appropriately called Scorer.java. Here’s a listing of the

Scorer.java source:

/* Scorer.java */

package org.shanky.flex.examples.nbascorers;

import java.io.Serializable;

public class Scorer implements Serializable {

private static final long serialVersionUID = 5529587875471400663L;

private int scorerId;

private String firstName;

private String lastName;

private int totalScore;

private int position;

public Scorer() {

super();

}

public Scorer(int scorerId, String firstName, String lastName,

int totalScore, int position) {

super();

this.scorerId = scorerId;

this.firstName = firstName;

this.lastName = lastName;

this.totalScore = totalScore;

this.position = position;

}

public int getScorerId() {

return scorerId;

}

public void setScorerId(int scorerId) {

this.scorerId = scorerId;

}

public String getFirstName() {

return firstName;

}

public void setFirstName(String firstName) {

this.firstName = firstName;

}

…// getters and setters for the lastName, totalScore and position.

INTEGRATING FLEX WITH JAVA USING SERVICES

205

}

The getter and setter methods for a few attributes are not included in the listing as they are implicitly

understood to be similar to the ones included. The complete source code is available in the book’s code

download bundle.

A collection of the top scorers is returned by a Java service class named TopScorersService.java. The

TopScorersService class has a method, named getTopScorers, that returns a collection of top NBA

scorers. The simple example here needs to return a list of just the all-time top ten scorers. Therefore,

getTopScorers ends up calling a private method called getAllTimeTop10Scorers, which creates and

returns an array list of the top ten scorers. To keep things flexible and allow alternative ways to access and

return the top scorers list, the getTopScorers method is parameterized, with time interval and collection

size as the parameters. Time interval is defined as an enumeration type with ALL_TIME and CURRENT the

two possible values. You can extend this enumeration class to include other time horizons, such as last

five years, last twenty years, or any such period. As for the collection size, top ten suffices for now. Ideally,

you may want to allow this to be equal to any arbitrary integer, say 20, 100, 350, or 10,000. The

implementation of the methods is simple and all the logic resides inline, but the example can be easily

extended to include an external data store and a data access intermediation layer. The

TopScorersService.java class is as follows:

/* TopScorersService.java */

package org.shanky.flex.examples.nbascorers;

import java.util.List;

import java.util.ArrayList;

public class TopScorersService {

public List<Scorer> getTopScorers(TimeInterval timeInterval, int collectionSize) {

if(timeInterval == TimeInterval.ALL_TIME && collectionSize == 10) {

return getAllTimeTop10Scorers();

} else {

return null;

}

}

private List<Scorer> getAllTimeTop10Scorers() {

List<Scorer> topScorersList = new ArrayList<Scorer>();

topScorersList.add(new

Scorer(1, "Kareem", "Abdul-Jabbar", 38387, 1));

topScorersList.add (new

Scorer(2, "Wilt", "Chamberlain", 31419, 2));

topScorersList.add (new

Scorer(3, "Karl", "Malone", 30599, 3));

topScorersList.add (new

Scorer(4, "Michael", "Jordan", 29277, 4));