ajdb debugger for .class files produced by ajc (early-access) ajdb -classpath path -D name = value -help -gui -read file -sourcepath dir -v -verbose :class :gc :jni workingdir dir -X option class arguments == Description The command `ajdb` is used to debug AspectJ and Java programs. In addition to its command line interface, `adjb` also has a standalone, Swing-based GUI interface. Note: As of the 1.0.3 release, AspectJ supports JSR-45, which provides source-level debugging from many source files per class and non-Java source files. JSR-45 is implemented in the J2SE 1.4 debugger support, so you may be able to use your existing debugger to step through AspectJ source code if both the source and target VM's are running under Java 1.4 or later. However, existing debuggers will display synthetic methods in the stack frame. -classpath path Specify where to find user class files. -D name = value Define the property name to have the value value . -help Print out ajdb 's usage summary. -read file Read this file for initializatoin commands. -sourcepath path Search this directory for source files. -gui -v | -verbose [:class | :gc | :jni] Print out class loading, garbage collection or dynamic library loading information. Defaults to class loading. -workingdir directory Set ajdb 's working directory. -X option Pass a non-standard option to the VM === Capabilities The AspectJ debugger implements all of ``jdb``'s commands. In addition, the command `workingdir` allow you to set the AspectJ working directory, and the breakpoint command, `stop on`, has been extended to allow the setting of breakpoint on a source file line. === Examples Suppose you want to debug the file spacewar/Ship.java found in the examples directory. At the command line start up the debugger: ` ajdb ` The debugger will first look for initialization files in your home or current directory called either `ajdb.ini` or `.ajdbrc` and execute the commands contained in them. A useful command to have in this file is the `source-path` command which tells the debugger where to find source files. For this example, we need to set the source path by: ` use C:\src ` To view the file to debug, type `list spacewar/Ship.java` which generates the following output: [source, java] .... /*209*/ void fire() { /*210*/ // firing a shot takes energy /*211*/ if (!expendEnergy(BULLET_ENERGY)) /*212*/ return; /*213*/ /*214*/ //create a bullet object so it doesn't hit the ship that's firing it /*215*/ double xV = getXVel() + BULLET_SPEED * (Math.cos(orientation)); /*216*/ double yV = getYVel() + BULLET_SPEED * (Math.sin(orientation)); /*217*/ /*218*/ // create the actual bullet /*219*/ new Bullet( /*220*/ getGame(), /*221*/ (getXPos() + ((getSize()/2 + 2) * (Math.cos(orientation))) + xV), /*222*/ (getYPos() + ((getSize()/2 + 2) * (Math.sin(orientation))) + yV), /*223*/ xV, /*224*/ yV); /*225*/ } .... This is different from `jdb` because it allows one to view files before the debugger has started. The `list` command has the following syntax: list list the source containing the location at which we are currently stopped (can only be used with a running VM) list source list the entire file source list source line list source line line of file source list source start-line end-line list the lines from start-line to end-line of file source To set a breakpoint in the method `Ship.fire`, we would could type `stop in spacewar.Ship.fire`. The following message appears notifying the user that the breakpoint has been noted but will not be set until the class has been loaded by the VM: [source, text] .... Deferring breakpoint spacewar.Ship.fire() It will be set after the class is loaded. .... To start Spacewar we type `run spacewar.Game`. When the breakpoint is set, the following message appears: [source, text] .... Set deferred breakpoint spacewar.Ship.fire() .... We are notified that we've hit the breakpoint: [source, text] .... Breakpoint hit: thread="Thread-2", spacewar.Ship.fire(), line=174, bci=0 209 void fire() { .... The prompt changes to present the thread that has broken, and we can view the current stack with the `where` command, as follows: [source, text] .... Thread-2[1] where [1] fire (spacewar\Ship.java:209) [2] run (spacewar\Robot.java:100) [3] run [class java.lang.Thread] .... Next, to stop on line 216 we type `stop on spacewar/Ship.java:216` The following message tells us the breakpoint was set: [source, text] .... Set breakpoint Ship.java:216 .... To continue execution, we type `cont` and the breakpoint at line 216 is hit [source, text] .... Breakpoint hit: thread="Thread-2", spacewar.Ship.fire(), line=216, bci=28 216 double yV = getYVel() + BULLET_SPEED * (Math.sin(orientation)); .... To view the visible local variables, we type `locals` and ajdb responds with: [source, text] .... Local variables xV = 12.242462584304468 .... To change the value of the local variable i to 15, we type `set xV = 16.1` [source, text] .... Changed 'xV' from '12.242462584304468' to '16.1' .... To see our changes we can print the value of `i` by the following: [source, text] .... print xV Value for printing 'xV' = 12.242462584304468 .... We can now type exit or quit to leave the debugger, and we receive the following message: [source, text] .... The application has exited. .... === The AspectJ debugger API The AspectJ debugger is implemented completely in Java and can be called as a Java class. The only interface that should be considered public is the method `org.aspectj.tools.debugger.Main.main(String[] args)` where `args` are the standard `ajc` command line arguments. This means that an alternative way to run the compiler is [source, text] .... java org.aspectj.tools.debugger.Main options class arguments .... You must additionally include `tools.jar` from your Java developer's kit in your classpath.