BOOKS FOR PROFESSIONALS BY PROFESSIONALS‘M
`
`Ian Newmarch
`
`A Programmer’s Guide
`to JiniT” Technology
`
`Up-to-date coverage of the newest IinilM features announced by Sun this year
`
`I
`
`Addresses important topics such as application architecture. user interfaces for JiniTM services,
`
`and how hardware devices and CORBA fit in with the IiniTM framework
`
`Tech reviewed by master JavaTM programmer and well-known columnist Bill Venner
`
`APress Media, LLC
`
`1
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`APPLE 1046
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`1
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`APPLE 1046
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`

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`A Programmer’s Guide to
`Jinim Technology
`
`IAN NEWMARCH
`
`APress Media, LLC
`
`libdocdel@fr.com
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`A Programmer’s Guide to IiniT'“I Technology
`
`Copyright ©2000 by Ian Newrnarch
`Originally published by Apress in 2000
`
`All rights reserved. No part of this work may be reproduced or transmitted in any form or by any
`means, electronic or mechanical. including photocopying, recording, or by any information
`storage or retrieval system, without the prior written permission of the copyright owner and the
`publisher.
`
`ISBN 978' 1- 893 1 15-804
`DO] 10.1007f978-1-4302'0860'0
`
`ISBN 978- 1-4302-0360-0 (eBool-I)
`
`Ti'ademarked names may appear in this book. Rather than use a trademark symbol with every
`occurrence of a trademarked name, we use the names onlyin an editorial fashion and to the
`benefit of the trademark owner. with no intention of infringement of the trademark.
`
`Editorial Directors: Dan Ap pieman, Gary Cornell. Karen Watterson
`
`Editor: Andy Carroll
`Production Editor: Kari Brooks
`
`Page Composition: Tony Ionick—Rappid Rabbit
`
`Artist: Karl Miyajima
`indexer: Carol Burbo
`
`Cover: Karl Miyajima
`
`The information in this book is distributed on an “as is" basis. without warranty. Although every
`precaution has been taken in the preparation of this work, neither the author nor Apress shall
`have any liability to any person or entity with respect to any loss or damage caused or alleged to
`be caused directly or indirectly by the information contained in this work.
`
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`Contents at a Glance
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`Introduction ..................................................................................................... xu:
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`Chapter 1 Overview of Jini ........................................................................ 1
`
`Chapter 2 Troubleshooting Jini
`Configuration Problems ............................................................................ 17
`
`Chapter 3 Discovering a Lookup Service ............................................. 23
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`Chapter 4 Entry Objects ............................................................................. 43
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`Chapter 5 Service Registration .............................................................. 49
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`Chapter 6 Client Search ............................................................................. 57
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`Chapter 7 Leasing ......................................................................................... 63
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`Chapter 8 A Simple Example ...................................................................... 83
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`Chapter 9 Choices for Service Architecture ................................... 109
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`Chapter 10 Discovery Management .......................................................... 153
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`Chapter 11
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`Join Manager ........................................................................... 161
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`Chapter 12 Security ................................................................................... 169
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`Chapter 13 More Complex Examples ........................................................ 193
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`Chapter 14 Remote Event ........................................................................... 235
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`Chapter 15 ServiceDiscoveryManager.................................................... 255
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`Chapter 16 Transaction ............................................................................. 271
`
`Chapter 17
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`LEGO MINDS TORMS .................................................................... 295
`
`Chapter 18
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`CORBA and Jini ....................................................................... 323
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`Chapter 19 User Interfaces for Jini Services ..................../........... 355
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`Chapter 20 Activation ............................................................................... 393
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`Index .................................................................................................................... 433
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`Contents
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`Introduction ..................................................................................................... xm
`
`Chapter 1 Overview of Jini ................................................................. 1
`
`Jini ............................................................................................................................... 1
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`Components .................................................................................................................. 2
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`Service Registration ............................................................................................ 3
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`Client Lookup ........................................................................................................... 5
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`Proxies ........................................................................................................................ 7
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`Client Structure .................................................................................................... 8
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`Server Structure .................................................................................................. 10
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`Partitioning an Application .......................................................................... 11
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`Support Services .................................................................................................. 13
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`HTTP Server ........................................................................................................ 13
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`RMI Daemon ....................................................................................................... 15
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`Summary ...................................................................................................................... 15
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`Chapter 2 Troubleshooting Jini
`Configuration Problems ............................................... 17
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`Java Packages ......................................................................................................... 17
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`Jini versions ......................................................................................................... 18
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`Contents
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`Jini Packages ......................................................................................................... 19
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`Lookup Service .......................................................................................................20
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`RMI Stubs .................................................................................................................. 20
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`Debugging ..................................................................................................................22
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`Summary ......................................................................................................................22
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`Chapter 3 Discovering a Lookup Service ................................23
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`Running a Lookup Service .................................................................................23
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`Reggie ................................................................................................................... 23
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`rrnid and IDK 1.3 ................................................................................................. 26
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`Unicast Discovecy.................................................................................................26
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`LookupLocator .................................................................................................... 27
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`InvalidLookupLocator......................................................................................... 27
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`Running the InvalidLookupLocator .................................................................. 29
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`Information from the LookupLocator ............................................................... 29
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`getRegistrar .......................................................................................................... 30
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`Running the UnicastRegister .............................................................................. 32
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`Broadcast Discovery ............................................................................................ 32
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`Groups .................................................................................................................. 33
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`LookupDiscovery................................................................................................. 33
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`DiscoveryListener ................................................................................................ 34
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`DiscoveryEvent .................................................................................................... 35
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`Staying Alive ......................................................................................................... 37
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`Running the MulticastRegister ........................................................................... 38
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`Broadcast Range .................................................................................................. 39
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`ServiceRegistrar ................................................................................................... 39
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`Contents
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`Information from the ServiceRegistrar ............................................................. 41
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`Summary ...................................................................................................................... 42
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`Chapter 4 Entry Objects ....................................................................... 43
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`Entry Class ............................................................................................................. 43
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`Attribute Matching Mechanism ......................................................................... 45
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`Restrictions on Entries ................................................................................... 46
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`Convenience Classes ............................................................................................ 46
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`Further Uses of Entries ................................................................................... 47
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`Summary ...................................................................................................................... 48
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`Chapter 5 Service Registration ..................................................... 49
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`ServiceRegistrar .................................................................................................. 49
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`ServiceItem ............................................................................................................. 49
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`Registration ........................................................................................................... 51
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`ServiceRegistration ............................................................................................ 51
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`The SimpleService Program ............................................................................... 52
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`Running the SimpleService ................................................................................ 53
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`Information from the ServiceRegistration ........................................................ 54
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`Service ID ............................................................................................................. 54
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`Entries ...................................................................................................................... 55
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`Summary ...................................................................................................................... 55
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`Contents
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`Chapter 6 Client Search .......................................................................57
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`Searching for Services with the ServiceRegistrar ............................. 57
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`Receiving the ServiceMatches Object ......................................................... 60
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`Matching Services ................................................................................................. 61
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`Summary ...................................................................................................................... 62
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`Chapter 7 Leasing....................................................................................... 63
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`Requesting and Receiving Leases .................................................................. 63
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`Cancellation ......................................................................................................... 65
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`Expiration ............................................................................................................. 65
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`Renewing Leases ..................................................................................................... 65
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`Granting and Handling Leases ......................................................................... 66
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`Abstract Lease ...................................................................................................... 67
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`Landlord Lease Package ...................................................................................... 68
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`Summary ...................................................................................................................... 81
`
`Chapter 8
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`A Simple Example ............................................................... 83
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`Problem Description ............................................................................................ 83
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`Service Specification ........................................................................................ 86
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`common Classes ....................................................................................................... 87
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`MIMEType ........................................................................................................... 87
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`FileClassifier Interface ........................................................................................ 89
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`The Client ................................................................................................................ 90
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`Contents
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`Unicast Client ...................................................................................................... 90
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`Multicast Client ................................................................................................... 94
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`Exception Handling ............................................................................................ 96
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`The Service Proxy ................................................................................................ 97
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`Uploading a Complete Service ........................................................................ 98
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`FileClassifier Implementation ........................................................................... 99
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`FileClassifierServer Implementation ................................................................. 99
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`Client Implementation ..................................................................................... 104
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`What Classes Need to Be Where? ..................................................................... 104
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`Running the FileClassifier ................................................................................ 1 06
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`Summary .................................................................................................................... 1 07
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`Chapter 9 Choices for Service Archi tecture .................... 109
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`Proxy Choices ....................................................................................................... 109
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`Proxy Is the Service ........................................................................................... 109
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`RMI Proxy .......................................................................................................... 1 I 0
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`Non-RMI Proxy.................................................................................................. 112
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`RMI and Non—RMI Proxies ............................................................................... 1 14
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`RMI Proxy for FileClassifier ...................................................................... 115
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`What Doesn’t Change ....................................................................................... 1 15
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`RemoteFileClassifier ......................................................................................... 1 1 6
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`FileClassifierImpl .............................................................................................. 1 l 6
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`FileClassifierServer............................................................................................ 11 7
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`What Classes Need to Be Where? ..................................................................... 120
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`Running the RMI Proxy FileClassifier.............................................................. 122
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`Non -RMI Proxy for FileClassifier ............................................................. 123
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`FileClassifierProxy ............................................................................................. 124
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`Contents
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`FileServerImpl ................................................................................................... 126
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`Service Provider ................................................................................................. 128
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`What Classes Need to Be Where? ..................................................................... 131
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`Running the RMI Proxy FileClassifier ............................................................. 132
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`RMI and non-RMI Proxies for FileClassifier ........................................ 133
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`FileClassiflerProxy ............................................................................................. 133
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`ExtendedFileClassifier ...................................................................................... 134
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`ExtendedFileClassifierImpl .............................................................................. 135
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`FileClassifierServer ............................................................................................ 137
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`What Classes Need to Be Where? ..................................................................... 139
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`Using Other Services ........................................................................................ 140
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`Heart Interface ................................................................................................... 142
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`HeartServer ........................................................................................................ 142
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`HeartClient ......................................................................................................... 145
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`Heart Implementation ...................................................................................... 147
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`Summary .................................................................................................................... 152
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`Chapter 10 Discovery Management ................................................... 153
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`Finding Lookup Locators ................................................................................. 153
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`LookupLocatorDiscovery.................................................................................... 155
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`LookupDiscoveryManager.................................................................................... 157
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`Summary .................................................................................................................... 159
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`Chapter 11 Join Manager........................................................................ 161
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`Jini 1.1 JoinManager ........................................................................................ 161
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`Contents
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`Jini 1 . 0 JoinManager ........................................................................................ 163
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`Getting Information from IoinManager .......................................................... 166
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`Summary .................................................................................................................... 167
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`Chapter 12 Securi ty.................................................................................. 169
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`Getting Going with No Security .................................................................. 169
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`Why AllPermission Is Bad ............................................................................... 170
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`Removing AllPermission ................................................................................... 172
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`Jini with Protection ........................................................................................ 173
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`Service Requirements ........................................................................................ 174
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`Client Requirements .......................................................................................... 176
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`RMI Parameters ..................................................................................................... 178
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`ServiceRegistrar ................................................................................................ 179
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`Transaction Manager and Other Activatable Services ...................... 180
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`rmid ........................................................................................................................... 182
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`rmid and IDK 1.3 ............................................................................................... 183
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`Being Paranoi ac ................................................................................................... 186
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`Protection Domains .......................................................................................... 1 86
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`Signing Standard Files ...................................................................................... 187
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`Signing Other Services ...................................................................................... 188
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`Permissions ......................................................................................................... 88
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`Putting It Together ............................................................................................ 1 89
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`Summary .................................................................................................................... 191
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`Contents
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`Chapter 13 More Complex Examples ................................................ 193
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`Where Are the Class Files? ........................................................................... 193
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`Problem Domain ............................................................................................... 193
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`NameEntry Interface ......................................................................................... 1 95
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`Naive Implementation ...................................................................................... 1 96
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`Factory Implementation ................................................................................... 199
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`Using Multiple Class Files ................................................................................. 201
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`Running Threads from Discovery ..................................................................204
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`Server Threads ...................................................................................................204
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`Join Manager Threads ....................................................................................... 207
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`Client Threads .................................................................................................... 207
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`Inexact Service Matching ...............................................................................209
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`Matching Using Local Services ....................................................................213
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`Finding a Service Once Only......................................................................... 221
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`Leasing Changes to a Service.......................................................................225
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`Leased FileClassifier .......................................................................................... 226
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`The FileClassifierLeasedResource Class .......................................................... 228
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`The FileClassifierLeaseManager Class ............................................................. 229
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`The FileClassifierLandlord Class ...................................................................... 231
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`Summary ....................................................................................................................233
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`Chapter 14 Remote Events .....................................................................235
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`Event Models .......................................................................................................... 235
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`Remote Events ....................................................................................................... 236
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`Event Registration ............................................................................................ 238
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`Contents
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`Listener List ....................................................................................................... 239
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`Single Listener ................................................................................................... 239
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`Multiple Listeners ............................................................................................ 241
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`Listener Source ................................................................................................... 242
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`File Classifier with Events ........................................................................ 244
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`Monitoring Changes in Services .................................................................. 249
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`Summary .................................................................................................................... 254
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`Chapter 15 ServiceDiscoveryManager ........................................... 255
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`ServiceDiscoveryManager Interface ........................................................... 255
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`ServiceItemFilter Interface ........................................................................ 256
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`Finding a Service Immediately .................................................................... 257
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`Using a Filter ..................................................................................................... 259
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`Building a Cache of Services ...................................................................... 262
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`Running the CachedClientLookup .................................................................. 265
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`Monitoring Changes to the Cache ................................................................ 266
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`Summary .................................................................................................................... 269
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`Chapter 16 Transactions ....................................................................... 271
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`Transaction Identifiers ................................................................................. 271
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`TransactionManager ............................................................................................ 272
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`TransactionParticipant ................................................................................... 223
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`Mahalo ...................................................................................................................... 273
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`Contents
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`A Transaction Example ......................................................................................274
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`PayableFileClassifierImpl ................................................................................. 276
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`Accountslmpl ..................................................................................................... 282
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`Client .................................................................................................................. 287
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`Summary ....................................................................................................................294
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`Chapter 17 LEGO MINDSTORMS ................................................................295
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`Making Hardware into Jini Services ......................................................... 295
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`MINDSTORMS .............................................................................................................. 296
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`MINDSTORMS as a Jini Service ....................................................................... 296
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`RCXPort .................................................................................................................... 297
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`RCX Programs ..........................................................................................................299
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`Jini Classes .......................................................................................................... 301
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`Getting It Running ............................................................................................ 307
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`Entry Objects far a Robot ............................................................................. 315
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`A Client-Side RCX Class ................................................................................. 316
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`Higher-Level Mechanisms: Not Quite C ..................................................... 317
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`Summary .................................................................................................................... 322
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`Chapter 18 CORBA and Jini ..................................................................323
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`CORBA ......................................................................................................................... 323
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`CORBA to Java Mapping ...................................................................................... 325
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`Jini Proxies .......................................................................................................... 326
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`Contents
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`A Simple CORBA Example ................................................................................... 328
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`CORBA Server in Java ....................................................................................... 328
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`CORBA Client in Java ........................................................................................ 330
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`Iini Service ......................................................................................................... 331
`
`Iini Server and Client ........................................................................................ 334
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`Building the Simple CORBA Example ............................................................. 334
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`Running the Simple CORBA Example ............................................................. 335
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`CORBA Implementations ................................................................................. 335
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`Room-Booking Example ........................................................................................ 336
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`CORBA Objects .................................................................................................. 337
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`Multiple Objects ................................................................................................ 340
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`Exceptions .......................................................................................................... 344
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`Interfaces for Single Thin Proxy ....................................................................... 345
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`RoomBookingBridge Implementation ............................................................ 347
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`Other Classes ..................................................................................................... 351
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`Building the Room-Booking Example ............................................................. 352
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`Running the Room-Booking Example ............................................................. 352
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`Migrating a CORBA Client to Jini ............................................................. 353
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`Jini Service as a CORBA Service ................................................................ 354
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`Summary .................................................................................................................... 354
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`Chapter 19 User Interfaces for Jini Services ................. 355
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`User Interfaces as Entries ........................................................................... 355
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`Us er Interfaces from Factory Objects ..................................................... 356
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`Current Factories .............................................................................................. 358
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`Marshalling Factories ...................................................................................... 358
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`Conten