Using the Java API http java sun comj

Using the Java API http: //java. sun. com/j 2 se/1. 3/docs/api/

Where’s the API?

Overview s w Vie s e g a k c a P s a l C s e s n o i t a orm Ma f n I in a e Ar

General approach • If you know the name of the package, click it in the upper left panel; or click All Classes • Click on the class in the lower left panel • Scroll in the right pane to find the summary of the field, method, or constructor you want – Or just read the general description • For more information, click the link in the summary to go to the detailed information

The Packages panel • Choose the package you are interested in • Or, choose All Classes • Classes in java. lang are automatically imported into every program--you don’t have to do it yourself

The Classes panel • This panel shows both classes and interfaces • We haven’t yet talked about interfaces • Note that some classes have names similar to primitive types (Boolean, Byte, Character)

The links bar • • Overview is where you start out Index is handy for looking up methods Help is the obvious If you don’t like frames, you can choose NO FRAMES • Deprecated methods are those that have been replaced by better methods and should not be used

The main information area • • General description of the class Field summary • In each case, the Constructor summary “summary” is the first Method summary sentence of the “detail” Field detail Constructor detail Method detail

Reading the method descriptions I • An example from the String class: – public char. At(int index) • Returns the character at the specified index – – – public means accessible from anywhere char is the return type char. At is the name of the method int is the type of parameter expected index is just a suggestive name Example use: char first. Char = my. Str. char. At(0);

Reading the method descriptions II • Another example from the String class: – public static String value. Of(int i) • Returns the string representation of the int argument. – – – public means accessible from anywhere static means this is a class method (see use below) String is the return type, and is a hyperlink value. Of is the name of the method int is the type of parameter expected i is just a suggestive name – Example use: String numeral = String. value. Of(m / n);

How was this documentation produced? • All Java documentation was produced by the javadoc program from javadoc (or just doc) comments in the source code • Your doc comments can be used in the same way to produce professional-looking documentation • The Interface menu item in Blue. J does the same basic thing as javadoc – Like most things in Blue. J, fancy features have been omitted in the interests of simplicity

Value of the API • Version packages classes methods Java 1. 0 8 212 1545 Java 1. 1 23 504 3851 Java 1. 2 60 1781 15060 Java 1. 3 77 2130 17158 Java. 14 ? ? ? • You can only learn a small fraction of these • When you learn the kinds of things that are in the API, and learn to find your way around in it, you become a far more effective and efficient programmer • A good craftsman knows his/her tools

The End