Building Portals with the Java Portlet API (Expert's Voice) (v. 2)

418 Pages·2004·6.63 MB·English

by  Jeff Linwood

CYAN YELLOW
MAGENTA BLACK
PANTONE 123 CV
EMPOWERING PRODUCTIVITY FOR THE JAVA DEVELOPER THE EXPERT’S VOICE® IN JAVA
Building Portals with the Java Portlet API
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Dear Reader, ild aanndd XXDDoocclleett
How do you bring your existing applications into the portal? How do you inte- i
n
grate your content management system and search engine with the portal? g
How do you get started with the portlet API? We show you how to solve real w P
problems, like the ones we have seen as consultants and software developers.
io
We cover the portlet API in depth, explaining the concepts and classes with thr
example scenarios and code. When you are comfortable with the portlet API, t
JPerof fS Ltrinuwts oAopdp,liccoa-tiaountshor of wmee netx,a cmhianret ipnogr, tpale rinsotengarlaiztiaotnio tne,c ahpnpiqliuceast,i oSnin agnled S cigonn-tOennt, csoynndteicnat tmioann, aagned- theals Building
searching. J
We believe that with the remarkable cooperation in unifying the portlet API
across many different vendors, using standards for portals is now the best a
choice. Our examples will therefore run on any portal that supports the portlet Portals
API. We avoid proprietary tools, instead showing how to incorporate several v
open source software projects into your portlets, including XDoclet, Apache with the
a
Jakarta Lucene, and JFreeChart.
Our backgrounds as developers and consultants lead us to look for books

that concentrate on solving real problems with new technologies, not just
P
explaining their details. We hope that this book will help you to solve problems
Java Portlet API
using the portlet API.
o
Jeff Linwood and Dave Minter
Dave Minter r
t
l
APRESS JAVA ROADMAP e
Beginning
t
J2EE 1.4
Building
Beginning Enterprise Java Learn how to create portlet applications,integrate existing web
Portals with the
Java Objects Development on a Budget A
Java Portlet API applications,and incorporate XDoclet,Apache Jakarta Lucene,
Beginning
JSP 2
P JFreeChart,and other open source projects
I
Join online discussions:
forums.apress.com
SOURCECODEONLINE
FOR PROFESSIONALS BY PROFESSIONALS™
www.apress.com a
n
dL Jeff Linwood
Min
w
ISBN 1-59059-284-0 ino and Dave Minter
54999 teo
US $49.99 rd
Foreword by Ian Griffiths
Shelve in
Java
User level:
Intermediate–Advanced 6 89253 15840 1 9 781590 592847
this print for content only—size & color not accurate spine = 0.790" 416 page count
Praise for Building Portals with the Java Portlet API:
“The book gives a solid introduction to developing a portal . . .
Clearly the authors understand portal development and know how
to pass that information on to their readers.”
—Thomas Paul, JavaRanch (www.javaranch.com)
“The text is well written and easy to read;graphics and illustrations
are used sparingly and to great effect.”
— Jack Herrington, Code Generation Network (www.codegeneration.net)
2840chFM.qxd 7/13/04 12:43 PM Page i
Building Portals with
the Java Portlet API
JEFF LINWOOD, DAVE MINTER
2840chFM.qxd 7/13/04 12:43 PM Page ii
Building Portals with the Java Portlet API
Copyright © 2004 by Jeff Linwood, Dave Minter
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2840chFM.qxd 7/13/04 12:43 PM Page iii
Contents at a Glance
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi
About the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii
About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvii
Chapter 1 Introduction to Portals and Portlets . . . . . . . . . . . . . .1
Chapter 2 Portlet Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Chapter 3 The Portlet Life Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Chapter 4 Portlet Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Chapter 5 Using Servlets and JavaServer Pages
with Portlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
Chapter 6 Packaging and Deployment Descriptors . . . . . . . . . . . .159
Chapter 7 Portal and Portlet Configuration . . . . . . . . . . . . . . . .185
Chapter 8 Security and Single Sign-On . . . . . . . . . . . . . . . . . . . . . .209
Chapter 9 RSS and Syndication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .239
Chapter 10 Integrating the Lucene Search Engine . . . . . . . . . . .255
Chapter 11 Personalization and User Attributes . . . . . . . . . . . . .281
Chapter 12 Web Services for Remote Portlets (WSRP)
and Application Syndication . . . . . . . . . . . . . . . . . . . . . .295
Chapter 13 Exposing an Existing Application As
a Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307
Chapter 14 Charting with JFreeChart . . . . . . . . . . . . . . . . . . . . . . . . .339
Chapter 15 Content Management Systems . . . . . . . . . . . . . . . . . . . . . . .359
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .381
iii
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Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi
About the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii
About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvii
Chapter 1 Introduction to Portals and Portlets . . . . . 1
Providing a Solution with Portals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Designing the Portal’s Information Architecture . . . . . . . . . . . . . . . .2
Portal Application Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Building Portlets with the Portlet API . . . . . . . . . . . . . . . . . . . . . . . . . .6
Providing Technical Solutions with Portals . . . . . . . . . . . . . . . . . . . . . .7
Security and Single Sign-On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Content Syndication and RSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Searching Content from the Portal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Portals and Web Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Integrating Existing Applications into the Portal . . . . . . . . . . . . . .9
Using Charts in the Portal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Content Management and Portlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Chapter 2 Portlet Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
First Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Building the Portlet Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Deploying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Portlet Programming 101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
GenericPortlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Portlet Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Portlet Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Enhancing the Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Web.xml Deployment Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
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Contents
Packaging and Deploying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Chapter 3 The Portlet Life Cycle . . . . . . . . . . . . . . . . . . . . . . . 41
The Portlet Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Creation of the Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Request Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Destroying the Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Threading Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
Chapter 4 Portlet Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Portlet Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Render Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Action Request and File Uploading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Portlet Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Render Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Action Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Portlet Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Sessions and Interportlet Communication . . . . . . . . . . . . . . . . . . . . . . .102
Content Markup Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105
Portlet Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Window States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Caching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
Style Sheets and the User Experience . . . . . . . . . . . . . . . . . . . . . . . . . .116
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
Chapter 5 Using Servlets and JavaServer Pages
with Portlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Portlets, Servlets, and JSP Design Goals . . . . . . . . . . . . . . . . . . . . . .119
Portlet Request Dispatcher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
Request and Response Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
Session Management Between a Portlet and a Servlet
or JSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131
Creating a Form in JSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
Using the Portlet JSP Tag Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
To-Do List Portlet Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
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Contents
The web.xml Deployment Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153
Directory Structure of the Application . . . . . . . . . . . . . . . . . . . . . . . .153
Complete Code Listing for the To-Do List Portlet . . . . . . . . . . . .154
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158
Chapter 6 Packaging and Deployment
Descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Portlet Application Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
Versioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
Portlet Application Deployment Descriptor Structure . . . . . . . . .160
Web Application Deployment Descriptor . . . . . . . . . . . . . . . . . . . . . . . . .170
XDoclet Portlet Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
Chapter 7 Portal and Portlet Configuration. . . . . . . . . 185
Using the PortalContext to Retrieve Information
About the Portal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
Using the PortletConfig Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
Using Portlet Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .208
Chapter 8 Security and Single Sign-On . . . . . . . . . . . . . . . 209
Portlet Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .210
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .238
Chapter 9 RSS and Syndication . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Overview of RSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .239
Walking Through an Example RSS File . . . . . . . . . . . . . . . . . . . . . . . . . .240
RSS Browsers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .246
Displaying Syndicated Information in Portlets . . . . . . . . . . . . . . . .247
Syndicating Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .249
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .253
Chapter 10 Integrating the Lucene
Search Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Overview of Lucene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .255
Downloading and Installing Lucene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .256
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Contents
Lucene Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .256
Building an Index with Lucene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .263
Designing a Portlet to Search the Index . . . . . . . . . . . . . . . . . . . . . . .270
Developing a Portlet for Lucene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .271
Indexing Other Types of Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .277
Lucene and Different Types of Content . . . . . . . . . . . . . . . . . . . . . . . . .279
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .280
Chapter 11 Personalization and User
Attributes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
Making a Good Impression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .281
Making Choices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .289
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294
Chapter 12 Web Services for Remote Portlets
(WSRP) and Application Syndication. . . . . . 295
WSRP Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .295
WSRP and the Java Portlet API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .298
WSRP Markup in Content Fragments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .299
Using WSRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .304
Common Problems with Application Syndication . . . . . . . . . . . . . . . . .304
Future Directions of WSRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .306
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .306
Chapter 13 Exposing an Existing Application
As a Portlet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Overview of the YAZD Forum Software . . . . . . . . . . . . . . . . . . . . . . . . . . .307
Deciding What to Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .309
Displaying Screens in a Portlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .312
Getting Configuration Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .332
Issues Encountered in Our Example . . . . . . . . . . . . . . . . . . . . . . . . . . . .338
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338
Chapter 14 Charting with JFreeChart. . . . . . . . . . . . . . . . . . . . 339
Building Charts and Graphs with JFreeChart . . . . . . . . . . . . . . . . . . .339
Chart Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .340
Basic JFreeChart Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .343
Providing Data to the Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .347
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