© O. Nierstrasz— P2 —1 Exceptions All Exception classes look like this! Define your own exception class to distinguish your exceptions from any other kind. public class AssertionException extends Exception { AssertionException() { super(); } AssertionException(String s) { super(s); } } The implementation consists of a default constructor, and a constructor that takes a simple message string as an argument. Both constructors call super() to ensure that the instance is properly initialized.

© O. Nierstrasz— P2 —2 Testing Assertions It is easy to add an assertion-checker to a class: private void assert(boolean assertion) throws AssertionException { if (!assertion) { throw new AssertionException("Assertion failed in LinkStack"); }  What should an object do if an assertion does not hold?  Throw an exception.

© O. Nierstrasz— P2 —3 Make Make is a Unix and Windows-based tool for managing dependencies between files. You can specify in a “Makefile”: Which files various targets depend on Rules to generate each target Macros used in the dependencies and rules Generic rules based on filename suffixes When files are modified, make will apply the minimum set of rules to bring the targets up-to-date.

© O. Nierstrasz— P2 —4 A Typical Makefile.SUFFIXES:.class.java.java.class :# generic rule javac $< CLASS = AbstractBoardGame.class AssertionException.class \ BoardGame.class GameDriver.class Gomoku.class Player.class \ Runner.class TestDriver.class TicTacToe.class all : TicTacToe.jar Test.jar# default target TicTacToe.jar : manifest-run $(CLASS)# target and dependents jar cmf manifest-run $(CLASS)# generation rule Test.jar : manifest-test $(CLASS) jar cmf manifest-test $(CLASS) clean : rm -f *.class *.jar

© O. Nierstrasz— P2 —5 Running make % make javac AbstractBoardGame.java javac GameDriver.java javac TestDriver.java jar cmf manifest-run TicTacToe.jar AbstractBoardGame.class AssertionException.class BoardGame.class GameDriver.class Gomoku.class Player.class Runner.class TestDriver.class TicTacToe.class jar cmf manifest-test Test.jar AbstractBoardGame.class AssertionException.class BoardGame.class GameDriver.class Gomoku.class Player.class Runner.class TestDriver.class TicTacToe.class % touch Runner.java % make Test.jar javac Runner.java jar cmf manifest-test Test.jar AbstractBoardGame.class AssertionException.class BoardGame.class GameDriver.class Gomoku.class Player.class Runner.class TestDriver.class TicTacToe.class

© O. Nierstrasz— P2 —6 RCS command overview ciCheck in revisions coCheck out revisions rcsSet up or change attributes of RCS files identExtract keyword values from an RCS file rlogDisplay a summary of revisions mergeMerge changes from two files into a third rcsdiffReport differences between revisions rcsmergeMerge changes from two RCS files into a third rcscleanRemove working files that have not been changed rcsfreezeLabel the files that make up a configuration

© O. Nierstrasz— P2 —7 Using RCS When file is checked in, an RCS file called file,v is created in the RCS directory: mkdir RCS# create subdirectory for RCS files ci file# put file under control of RCS Working copies must be checked out and checked in. co -l file# check out (and lock) file for editing ci file# check in a modified file co file# check out a read-only copy ci -u file# check in file; leave a read-only copy ci -l file# check in file; leave a locked copy rcsdiff file# report changes between versions

© O. Nierstrasz— P2 —8 Additional RCS Features Keyword substitution Various keyword variables are maintained by RCS: $Author$who checked in revision (username) $Date$date and time of check-in $Log$description of revision (prompted during check-in) Revision numbering: Usually each revision is numbered release.level Level is automatically incremented upon each check-in A new release is created explicitly: ci -r2.0 file

© O. Nierstrasz— P2 —9 Other tools Be familiar with the programming tools in your environment! memory inspection tools: like ZoneRanger help to detect other memory management problems, such as “memory leaks” zip and jar: store and compress files and directories into a single “zip file” awk, sed and perl: process text files according to editing scripts/programs

© O. Nierstrasz— P2 —10 What you should know!  How do make and Ant support system building?  What functionality does a version control system support?  When should you use a debugger?  What are breakpoints? Where should you set them?  What should you do after you have fixed a bug?  When should you use a profiler?  What is an IDE?

© O. Nierstrasz— P2 —11 Can you answer these questions?  When should you use Ant rather than make?  When should you use CVS rather than RCS?  How often should you checkpoint a version of your system?  When should you specify a version of your project as a new “release”?  How can you tell when there is a bug in the compiler (rather than in your program)?  How can you tell if you have tested every part of your system?