Programming Java 2 Micro Edition on Symbian OS A developer’s guide to MIDP 2.0 phần 10 pptx

Appendix 1CLDC Core Libraries System Classes java.lang.Class Instances of Class represent classes and interfaces in a running application.java.lang.Object The Object class is the root of

422 THE MARKET, THE OPPORTUNITIES AND SYMBIAN’S PLANS

• network bandwidth will improve, though not so dramatically

• network connections will always be available, reducing latency

• costs for persistent storage will continue to tumble and access speedswill increase dramatically as new memory technologies, such asFerroelectric RAM, Magnetic RAM and Ovonic memory, replaceNOR and NAND flash

• the resolution of screen displays will continue to improve, through adecrease in dot pitch as screen sizes will be limited by overall mobilephone ergonomics

There will also be market changes:

• ”smart houses” will become a reality: climate control, entertainmentand security systems will be controlled by a variety of devices,including mobile phones

• digital consumer goods will converge

Today, video cameras can take still images and digital cameras can recordvideo, and quite often both include MP3 players These capabilities aremoving into mobile phones: the current phones only support VGA,however the next generation of mobile phones will have megapixelresolution cameras (indeed a number of Japanese cameras already do).Many of today’s mobile phones come with FM radios and in the future

we are likely to see the inclusion of Digital Audio Broadcast radios InKorea, people can now use their mobile phones for credit card purchases.The consequence will be an explosion in the amount of data users store

on their mobile phone: audio, video, images, email and messaging Thiswill amount to gigabytes of storage

So, we leave you with a simple challenge: to use your developmentskills, and the knowledge and insight that we hope you have gainedfrom this book, to create the next killer Java service or application onSymbian OS

Appendix 1

CLDC Core Libraries

System Classes

java.lang.Class Instances of Class represent classes

and interfaces in a running application.java.lang.Object The Object class is the root of classes.java.lang.Runtime Every Java application has a single

instance of the Runtime class, whichallows the application to interface withthe environment in which it is running.Note that the Exit() method alwaysthrows a java.lang

SecurityException

useful fields and methods and it cannot

be instantiated Note that the Exit()method always throws a java.lang.SecurityException

java.lang.Thread A Thread is a unit of execution in a

program Multiple threads may beexecuted concurrently

java.lang.Runnable(interface) This interface should be implemented

by any class which is intended to beexecuted as threads A run() methodmust be defined by such a class.java.lang.Throwable The Throwable class is the superclass

of all errors and exceptions

Programming Java 2 Micro Edition on Symbian OS: A developer’s guide to MIDP 2.0 Martin de Jode

 2004 Symbian Ltd ISBN: 0-470-09223-8

424 CLDC CORE LIBRARIES

Data Type Classes

java.lang.Boolean The Boolean class wraps a value of

the boolean primitive type in an object

byte primitive type in an object.java.lang.Character The Character wraps a value of the

char primitive type in an object.java.lang.Integer The Integer class wraps a value of

the int primitive type in an object

long primitive type in an object.java.lang.Short The Short class wraps a value of the

short primitive type in an object.java.lang.String The String class represents character

strings

java.lang.Stringbuffer A StringBuffer implements a

mutable sequence of characters

Collection Classes

java.util.Vector The Vector class implements an array

of objects that can grow

java.util.Stack The Stack class represents a last in

first out stack of objects

java.util.Hashtable This class implements a hashtable,

which maps keys to values

java.util.Enumeration(interface) An object that implements the

Enumerationinterface generates aseries of elements, one at a time

Input/Output Classes

java.io.InputStream This abstract class is the superclass of

all classes representing an input stream

of bytes

java.io.OutputStream This abstract class is the superclass of

all classes representing an outputstream of bytes

java.io.ByteArrayInputStream A ByteArrayInputStream has an

internal buffer that contains bytes thatmay be read from the stream

CALENDAR AND TIME CLASSES 425

java.io.ByteArrayOutputStream This class implements an output

stream in which the data is written into

a byte array

java.io.DataInput(interface) The DataInput interface provides for

reading bytes from a binary stream andreconstructing from them data in any

of the primitive types

java.io.DataOutput(interface) The DataOutput interface provides

for converting data from any of theprimitive types to a series of bytes andwriting to a binary stream

java.io.DataInputStream A DataInputStream lets an

application read primitive data typesfrom an underlying input stream in amachine-independent way

java.io.DataOutputStream A DataOutputStream lets an

application write primitive data types

to an output stream in a portable way.java.io.Reader An abstract class for reading character

streams

java.io.Writer An abstract class for writing character

streams

java.io.InputStreamReader An InputStreamReader is a bridge

from byte streams to character streams

It reads bytes and translates them intocharacters according to a specifiedcharacter encoding

java.io.OutputStreamReader An OutputStreamReader is a

bridge from character streams to bytestreams Characters written to it aretranslated into bytes according to aspecified character encoding

java.io.PrintStream A PrintStream adds functionality to

another output stream, namely theability to print representations ofvarious data values conveniently

Calendar and Time Classes

java.util.Calendar The Calendar is an abstract class for

getting and setting dates using a set ofinteger fields such as YEAR, MONTH,DAY, etc

426 CLDC CORE LIBRARIES

instant in time with a millisecondprecision

java.util.TimeZone The TimeZone class represents a time

zone offset and also works out daylightsavings

Additional Utility Classes

java.util.Random An instance of this class is used to

generate series of pseudo-randomnumbers

performing basic numeric operations

Exception Classes

java.lang.Exception The Exception class and its

subclasses are a form of Throwablethat indicates conditions that areasonable application might want tocatch

java.lang.ClassNotFoundException Thrown when an application tries to

load in a class through its string nameusing the forName() method inClassclass

java.lang.IllegalAccessException Thrown when an application tries to

load in a class but the executingmethod does not have access to theclass definition, because the class is inanother package and is not public.java.lang.InstantiationException Thrown when an application tries to

create an instance of a class using thenewInstance()method in Classclass, but cannot instantiate it because

it is an interface or an abstract class or

it doesn’t have a default constructor.java.lang.InterruptedException Thrown when a thread is waiting,

sleeping or otherwise paused andanother thread interrupts it

java.lang.RuntimeException This is the superclass of exceptions that

can be thrown during the normaloperation of the Java Virtual Machine

EXCEPTION CLASSES 427

java.lang.ArithmeticException Thrown when an exceptional

arithmetic condition occurs

java.lang.ArrayStoreException Thrown to indicate that an attempt has

been made to store the wrong type ofobject in an array of objects

java.lang

ArrayIndexOutOfBoundsException

Thrown to indicate that an array hasbeen accessed with an illegal index.java.lang.ClassCastException Thrown to indicate that the code has

attempted to cast an object to asubclass of which it is not aninstance

java.lang

IllegalArgumentException

Thrown to indicate that a method hasbeen passed an illegal or inappropriateargument

java.lang

IllegalThreadStateException

Thrown when starting a Thread forthe second time

java.lang.NumberFormatException Thrown when trying to read an

Integerfrom a malformed String.java.lang

IllegalMonitorStateException

Thrown to indicate that a thread hasattempted to wait on an object’smonitor or to notify other threadswaiting on an object’s monitor withoutowning the specified monitor

java.lang

IndexOutofBoundsException

Thrown to indicate that an index ofsome sort (such as an index to anarray, to a string, or to a vector) is out

to the size of the string

java.lang

NegativeArraySizeException

Thrown if an application tries to create

an array with negative size

java.lang.NullPointerException Thrown when an application attempts

to use null in a case where an object isrequired

java.lang.SecurityException Thrown by the security manager to

indicate a security violation

java.util.EmptyStackException Thrown by methods in the Stack class

to indicate that the stack is empty.java.util.NoSuchElementException Thrown by the methods of an

Enumerationto indicate that thereare no more elements in the

enumeration

428 CLDC CORE LIBRARIES

java.io.EOFException Signals that an end of file or end of

stream has been reached unexpectedlyduring input

java.io.IOException Signals that an I/O exception of some

sort has occurred

java.io.InterruptedIOException Signals that an I/O operation has been

java.io.UTFDataFormatException Signals that a malformed UTF8 string

has been read in a data input stream or

by any class that implements the datainput interface

Error Classes

In contrast to the exception classes, the error-handling capabilities ofCLDC are limited to just three:

that indicates serious problems that areasonable application may not try tocatch

java.lang.VirtualMachineError Thrown to indicate that the Java Virtual

Machine is broken or has run out ofthe resources necessary for it tocontinue operating

java.lang.OutOfMemoryError Thrown when the Java Virtual

Machine cannot allocate an objectbecause it is out of memory and nomore memory can be made available

by the garbage collector

Catching an OutOfMemoryError is very good practice when oping for a resource-constrained device It allows the developer to try

devel-to free all the memory he can and maybe give the application anotherchance to perform the requested action In the worst case scenario, theapplication should be able to display a previously allocated dialog box

to inform the user that the application cannot continue

Appendix 2

MIDP Libraries

Networking Package

javax.microedition.io.Connection This interface is the most

basic type of genericconnection

javax.microedition.io.Connector This class is a placeholder for

the static methods used tocreate all the connectionobjects

javax.microedition.io.CommConnection This interface defines a

logical serial port connection.javax.microedition.io.ContentConnection This interface defines the

stream connection overwhich content is passed.javax.microedition.io.Datagram This is the generic datagram

interface

javax.microedition.io.DatagramConnectionThis interface defines the

capabilities that a datagramconnection must have.javax.microedition.io.HttpConnection This interface defines the

necessary methods andconstants for an HTTPconnection

javax.microedition.io.HttpsConnection This interface defines the

necessary methods andconstants to establish a securenetwork connection

javax.microedition.io.InputConnection This interface defines the

capabilities that an inputstream connection must have

Programming Java 2 Micro Edition on Symbian OS: A developer’s guide to MIDP 2.0 Martin de Jode

 2004 Symbian Ltd ISBN: 0-470-09223-8

430 MIDP LIBRARIES

javax.microedition.io.OutputConnection This interface defines the

capabilities that an outputstream connection must have.javax.microedition.io.PushRegistry This class maintains a list of

inbound connections

javax.microedition.io.SecureConnection This interface defines the

secure socket streamconnection

javax.microedition.io.SecurityInfo This interface defines the

methods for accessinginformation about a secureconnection

javax.microedition.io

ServerSocketConnection

This interface defines theserver socket streamconnection

javax.microedition.io.SocketConnection This interface defines the

socket stream connection.javax.microedition.io.StreamConnection This interface defines the

capabilities that a streamconnection must have.javax.microedition.io

StreamConnectionNotifier

This interface defines thecapabilities that a connectionnotifier must have

javax.microedition.io

UDPDatagramConnection

This interface defines adatagram connection whichknows the local end pointaddress

User Interface Classes

javax.microedition.lcdui.Alert A screen that shows data to

the user and waits for acertain period of timebefore proceeding to thenext screen

javax.microedition.lcdui.AlertType Provides an indication of

the nature of alerts

USER INTERFACE CLASSES 431

javax.microedition.lcdui.Canvas The base class for writing

applications that need tohandle low-level eventsand to issue graphicscalls for drawing to thedisplay

javax.microedition.lcdui.Choice This interface defines an API

for user interface componentsthat enable the user to selectfrom a predefined number ofchoices

javax.microedition.lcdui.ChoiceGroup A group of selectable

elements intended to beplaced within a Form.javax.microedition.lcdui.Command A construct that encapsulates

the semantic information of

an action

javax.microedition.lcdui.CommandListenerThis interface is used by

applications which need toreceive high-level events fromthe implementation

javax.microedition.lcdui.CustomItem A customizable element

which can be subclassed tointroduce new visual andinteractive elements to aForm

javax.microedition.lcdui.DateField An editable component for

presenting date and time(calendar) information thatmay be placed in a Form.javax.microedition.lcdui.Display Represents the manager of the

display and GUI capabilities

javax.microedition.lcdui.Form A Screen that contains an

arbitrary mixture of items:read-only text fields, editabletext fields, editable datefields, gauges, choice groupsand custom items

432 MIDP LIBRARIES

javax.microedition.lcdui.Gauge Implements a graphical

display, such as a bar graph,

javax.microedition.lcdui.Item A superclass for components

that can be added to aForm

javax.microedition.lcdui

ItemCommandListener

This interface is a listener typefor receiving notification ofcommands that have beeninvoked on Item objects.javax.microedition.lcdui

ItemStateListener

This interface is used byapplications which need toreceive events that indicatechanges in the internal state ofthe interactive items within aFormscreen

javax.microedition.lcdui.List A screen containing a list of

choices

javax.microedition.lcdui.Screen The common superclass of all

high-level user interfaceclasses

javax.microedition.lcdui.Spacer A blank, non-interactive Item

that has a settable minimumsize

javax.microedition.lcdui.StringItem A non-interactive Item that

can contain a string

javax.microedition.lcdui.TextBox A screen that allows the user

to enter and edit text

javax.microedition.lcdui.TextField An editable text component

that may be placed in a Form.javax.microedition.lcdui.Ticker Implements a ”ticker tape”, a

piece of text that runscontinuously across thedisplay

Game API

java.microedition.lcdui.game.GameCanvas This class provides the basis

for a game user interface

MIDLET CLASSES 433

java.microedition.lcdui.game.Layer An abstract class

representing a visualelement of a game

java.microedition.lcdui.game

LayerManager

The LayerManagermanages a series of Layers.java.microedition.lcdui.game.Sprite A basic visual element that

can be rendered with one

of several frames stored in

an image; different framescan be shown to animatethe Sprite

java.microedition.lcdui.game.TiledLayer A visual element composed

of a grid of cells that can befilled with a set of tileimages

Media API

java.microedition.media.Control A superclass for objects

used to control some mediaprocessing functions.java.microedition.media.Controllable An interface for obtaining

the Controls from anobject

java.microedition.media.Manager The access point for

obtainingsystem-dependentresources such as Playersfor multimedia processing.java.microedition.media.MediaException Indicates an unexpected

error condition in amethod

java.microedition.media.Player Controls the rendering of

time-based media data.java.microedition.media.PlayerListener An interface for receiving

asynchronous eventsgenerated by Players.java.microedition.media.control

ToneControl

An interface that enablesthe playback of

user-defined monotonictone sequences

java.microedition.media.control

VolumeControl

An interface formanipulating the audiovolume of a Player

compare two records Animplementation checkswhether they match or whattheir relative sort order is.javax.microedition.rms.RecordEnumeration An interface representing a

bi-directional record storerecord enumerator

javax.microedition.rms.RecordFilter An interface used to filter

records matching acriterion

javax.microedition.rms.RecordListener A listener interface for

receiving record changed,added or deleted eventsfrom a RecordStore.javax.microedition.rms.RecordStore A class representing a

record store

javax.microedition.rms

RecordStoreException

Thrown to indicate ageneral exception wasencountered in aRecordStoreoperation.javax.microedition.rms

RecordStoreFullException

Thrown to indicate that theoperation could not becompleted because theRecordStoreis full.javax.microedition.rms

and output through datastreams and serialization.

fundamental to the design

of the Java language Forexample, Object, which isthe root of the class

hierarchy

object classes, whichsupport a limited degree ofinteraction with thegarbage collector

interfaces for obtainingreflective informationabout classes andobjects

performingarbitrary-precision integer(BigInteger) and decimalarithmetic (BigDecimal)

implementing networkingapplications

interfaces for the securityframework

interfaces for parsing andmanaging certificates

436 MIDP LIBRARIES

interfaces for handling text,dates, numbers andmessages in a mannerindependent of naturallanguages

contain the collectionsframework, legacycollection classes, eventmodel, date and timefacilities,

internationalization andmiscellaneous utility classessuch as string tokenizer andrandom number generator

and writing the JAR fileformat, which is basedupon standard ZIP fileformat with an optionalmanifest file

and writing the standardZIP and GZIP file formats

generic connectionframework

Appendix 3

Using the Wireless Toolkit Tools

at the Command Line

This appendix provides developers with an insight into how the compile,pre-verify and packaging process works when using the Wireless Toolkit

at the command line

In the first instance we should make sure we have all the relevantbinaries within the view of our command line Some paths, therefore, need

to be set Assuming the J2ME Wireless Toolkit 2.1 has been installed toC:\WTK21 we should set the development platform’s PATH environmentvariable to that directory On a Windows desktop computer, the path tothe binaries should be set as follows:

C:> SET PATH=%PATH%;<install dir> \WTK21\bin

We will also need a Java compiler We should already have the latestJ2SE SDK installed on the machine, so we can use that compiler SetPATH as follows:

C:> SET PATH=%PATH%;<install dir> \JavaSoft\j2sdk1.4.2\bin

Now we should be able to use both the compiler and pre-verifier quiteeasily However, before we proceed we should also add a couple ofenvironment variables to make MIDlet creation a little easier We need todirect the commands towards the MIDP API and the other J2ME classes.Therefore we should set the following variables:

C:> SET J2MEHOME=<install dir> \WTK21

C:> SET MIDPAPI=%J2MEHOME% \lib\midpapi20.jar

C:> SET J2MECLASSPATH=%J2MEHOME% \wtklib\kenv.zip;

%J2MEHOME% \wtklib\kvem.jar;%J2MEHOME%\wtklib\lime.jar;

%J2MEHOME% \lib\cldcapi10.jar

Programming Java 2 Micro Edition on Symbian OS: A developer’s guide to MIDP 2.0 Martin de Jode

 2004 Symbian Ltd ISBN: 0-470-09223-8

438 USING THE WIRELESS TOOLKIT TOOLS AT THE COMMAND LINE

Now that some handy variables have been set, we can try to create

a MIDlet suite Once the classes have been written, they need to becompiled The following command should be used to compile all theclasses in the current directory and then put them in a previously createddirectory, tmpclasses Note that we have specified the classpath of theMIDP API to make sure the compiler knows to compile against the CLDCand MIDP classes, otherwise the classes may be compiled against theJ2SE SDK

C: \WTK20\apps\Example\src>javac -d tmpclasses -bootclasspath %MIDPAPI%

-classpath %J2MECLASSPATH% *.java

Once this has been completed, all the compiled class files can beseen in the tmpclasses directory We should now pre-verify them Bytyping the word preverify at the command line the following helpinformation appears showing the options available

Usage: preverify [options] classnames|dirnames

where options include:

-classpath <directories separated by ';'> Directories in which to look for classes

-d <directory> Directory in which output is written (default is

./output/)

-cldc Checks for existence of language features prohibited by CLDC (native methods, floating point and finalizers)

-nofinalize No finalizers allowed

-nonative No native methods allowed

-nofp No floating point operations allowed

@<filename> Read command line arguments from a text file Command line arguments must all be on a single line; directory names must be enclosed in double quotes(")

There are two options of interest to us here The -classpath option,which will specify which target API should be verified against, and the -doption, which specifies the output directory for these verified files Thefollowing command should be issued in the current directory:

C: \WTK20\apps\Example\src > preverify -classpath %MIDPAPI%;tmpclasses

-d classes tmpclasses

The pre-verified files will now be in the classes directory Thesefiles are ready for packaging into a MIDlet suite For this we use the jarcommand:

C: \WTK20\apps\Example\src> jar -cvf MyMidlet.jar classes/*

In this case we have asked the jar command to create a JAR filecalled MyMidlet.jar from all the files stored in the directory structureunder classes/

Appendix 4

Developer Resources and Bibliography

Download code for this book from

Sony Ericsson www.sonyericsson.com

Online Developer Resources

440 DEVELOPER RESOURCES AND BIBLIOGRAPHY

RESOURCES MENTIONED IN THIS BOOK AND ADDITIONAL MATERIAL 441

442 DEVELOPER RESOURCES AND BIBLIOGRAPHY

Sun (2003)The CLDC HotSpot Implementation Virtual Machine,White Paper

Forum Nokia (2003)Setting Up and Using the Bluetooth Testing

Environment for Series 60 Platform

http://forum.nokia.com

Hopkins, B and Anthony, R (2003)Bluetooth for Java, Apress

Java Community Process, JSR 82: Java APIs for Bluetooth WirelessTechnology

RESOURCES MENTIONED IN THIS BOOK AND ADDITIONAL MATERIAL 443

Sun, J2ME Wireless Toolkit 2.1 Download

Allin, J (2001)Wireless Java for Symbian Devices, Wiley

Buschmann, F., Meunier, R., Rohnert, H., Sommerland, P and Stal, M.(1996) Pattern-Oriented Software Architecture: A system of patterns,Wiley

Embedded Microprocessor Benchmark Consortium, GrinderBench

Lurie, J (2001) Develop a Generic Caching Service to Improve mance, Java World

Perfor- cache p.html

Shirazi, J (2003)Java Performance Tuning, O’Reilly

Sosnoski, D M (1999)Smart Object-management Saves the Day

performance.html

www.javaworld.com/javaworld/jw-11-1999/jw-11-Chapter 8

ARC Group

www.arcgroup.com

444 DEVELOPER RESOURCES AND BIBLIOGRAPHY

eWeek, Enterprise news and reviews

Appendix 5

Specifications of Symbian OS Phones

Additional technical information on a range of phones can be found at

www.symbian.com/phones

Please note that this is a quick guide to Symbian OS phones For fullspecifications, C++ developers retrieve extended information using HALAPIs or check the manufacturer’s website

Programming Java 2 Micro Edition on Symbian OS: A developer’s guide to MIDP 2.0 Martin de Jode

 2004 Symbian Ltd ISBN: 0-470-09223-8

446 SPECIFICATIONS OF SYMBIAN OS PHONES

Nokia 9210i

MIDP 1.0 PersonalJava 1.1.1 JavaPhone

Memory available to user 40 MB