ajc compiler for the AspectJ language ajc Options file... @file... -argfile file... The command ajc compiles AspectJ and Java language source files into class files. Options and files may be specified directly on the command line, or indirectly by naming a file which contains them. The arguments after the options specify the file(s) to compile. Files may be listed directly on the command line, or listed in a file. The @file and -argfile file forms are equivalent, and are interpreted as meaning all the files listed in the specified file. Each line in these files should contain one option or filename. Comments, as in Java, start with // and extend to the end of the line. NB: You must explicitly pass ajc all of the source files necessary for the compilation. When you are compiling source files containing aspects or pointcuts, be sure to include the source files for any types affected by the aspects or picked out by the pointcuts. (If you wish to exclude types from the scope affected by the aspect, change the corresponding pointcut or declaration.) This is necessary because, unlike javac, ajc does not search the sourcepath for classes. -verbose Output messages about what ajc is doing -version Print the version of ajc -nocomments Don't generate any comments into the woven code. Only relevant with -preprocess mode. -emacssym Generate symbols used by AJDE for Emacs -usejavac Use javac to generate .class files -preprocess Don't try to generate any .class files. Generate regular Java code into workingdir -workingdir Directory Specify where to place intermediate .java files Directory defaults to ./ajworkingdir. Only relevant with -usejavac or -preprocess modes. -O Optimize; may hinder debugging or enlarge class files -d Directory Specify where to place generated .class files Directory defaults to the current working dir -classpath Path Specify where to find user class files -bootclasspath Path Override location of bootstrap class files -extdirs Path Override location of installed extensions -argfile File the file is a line-delimited list of arguments these arguments are inserted into the argument list -encoding Encoding Specify character encoding used by source files -source 1.4 Specify support for assertions according to the 1.4 Java language. This will treat assert as a keyword and will implement assertions according to the 1.4 language spec. -lenient Be extra-lenient in interpreting the java specification This allows some statements that some compilers consider errors. -strict Be extra-strict in interpreting the java specification This signals errors for some statements that many compilers don't catch, and generates code strictly according to the Java Language Specification, even though such code may not run on 1.2 VMs. ajc accepts source files with either the .java extension or the .aj extension. We normally use .java for all of our files in an AspectJ system -- files that contain aspects as well as files that contain classes. However, if you have a need to mechanically distinguish files that use AspectJ's additional functionality from those that are pure Java we recommend using the .aj extension for those files. We'd like to discourage other means of mechanical distinction such as naming conventions or sub-packages in favor of the .aj extension. Filename conventions are hard to enforce and lead to awkward names for your aspects. Instead of TracingAspect.java we recommend using Tracing.aj (or just Tracing.java) instead. Sub-packages move aspects out of their natural place in a system and can create an artificial need for privileged aspects. Instead of adding a sub-package like aspects we recommend using the .aj extension and including these files in your existing packages instead. AspectJ is a compatible extension to the Java programming language. The AspectJ compiler adheres to the The Java Language Specfication, Second Edition and to the The Java Virtual Machine Specification, Second Edition and runs on any Java 2 compatible platform. The code it generates runs on any Java 1.1 or later compatible platform. Compile two files: ajc HelloWorld.java Trace.java To avoid specifying file names on the command line, list source files in a line-delimited text argfile. Source file paths may be absolute or relative to the argfile, and may include other argfiles by @-reference. The following file sources.lst contains absolute and relative files and @-references: Gui.java /home/user/src/Library.java data/Repository.java data/Access.java @../../common/common.lst @/home/user/src/lib.lst view/body/ArrayView.java Compile the files using either the -argfile or @ form: ajc -argfile sources.lst ajc @sources.lst Argfiles are also supported by jikes, javac, and ajdoc, so you can use the files in hybrid builds. However, the support varies: Only ajc accepts command-line options Jikes and Javac do not accept internal @argfile references. Jikes and Javac only accept the @file form on the command line. The AspectJ compiler 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.ajc.Main.main(String[] args) where args are the standard ajc command line arguments. This means that an alternative way to run the compiler is java org.aspectj.tools.ajc.Main option... file... To run in -usejavac mode, you must include in your classpath the tools.jar from your Java 2 developer's kit. Unlike traditional java compilers, the AspectJ compiler may in certain cases generate classfiles from multiple source files. Unfortunately, the Java class file format does not support multiple SourceFile attributes. So, in order to make sure all source file information is available, the AspectJ compiler may in some cases encode multiple filenames in the SourceFile attribute. Probably the only time you may see this format is when you view stack traces, where you may encounter traces of the format java.lang.NullPointerException at Main.new$constructor_call37(Main.java;SynchAspect.java[1k]:1030) where instead of the usual File:LineNumber format, you see File0;File1[Number1];File2[Number2] ... :LineNumber In this case, LineNumber is the usual offset in lines plus the "start line" of the actual source file. That means you use LineNumber both to identify the source file and to find the line at issue. The number in [brackets] after each file tells you the virtual "start line" for that file (the first file has a start of 0). In our example from the null pointer exception trace, the virtual start line is 1030. Since the file SynchAspect.java "starts" at line 1000 [1k], the LineNumber points to line 30 of SynchAspect.java. So, when faced with such stack traces, the way to find the actual source location is to look through the list of "start line" numbers to find the one just under the shown line number. That is the file where the source location can actually be found. Then, subtract that "start line" from the shown line number to find the actual line number within that file. Of course, AspectJ tools will do this decoding for you, and in a class file that comes from only a single source file, the AspectJ compiler generates SourceFile attributes consistent with traditional Java compilers.