JJTree

Description

Invokes the JJTree preprocessor for the JavaCC compiler compiler. It inserts parse tree building actions at various places in the JavaCC source that it generates. The output of JJTree is run through JavaCC to create the parser.

To use the jjtree task, set the target attribute to the name of the JJTree grammar file to process. You also need to specify the directory containing the JavaCC installation using the javacchome attribute, so that Ant can find the JavaCC classes. Optionally, you can also set the outputdirectory to write the generated JavaCC grammar and node files to a specific directory. Otherwise jjtree writes the generated JavaCC grammar and node files to the directory containing the JJTree grammar file. As an extra option, you can also set the outputfile to write the generated JavaCC grammar file to a specific (directory and) file. Otherwise jjtree writes the generated JavaCC grammar file as the JJTree grammar file with a suffix .jj.

This task only invokes JJTree if the grammar file is newer than the generated JavaCC file.

Parameters

Attribute Description Required
target The JJTree grammar file to process. Yes
javacchome The directory containing the JavaCC distribution. Yes
outputdirectory The directory to write the generated JavaCC grammar and node files to. If not set, the files are written to the directory containing the grammar file. No
outputfile The file to write the generated JavaCC grammar file to. If not set, the file is written with the same name as the JJTree grammar file but with a the suffix .jj. This is a filename relative to outputdirectory if specified, the project's basedir. No
buildnodefiles Sets the BUILD_NODE_FILES grammar option. This is a boolean option. No
multi Sets the MULTI grammar option. This is a boolean option. No
nodedefaultvoid Sets the NODE_DEFAULT_VOID grammar option. This is a boolean option. No
nodefactory Sets the NODE_FACTORY grammar option. This is boolean option. No
nodescopehook Sets the NODE_SCOPE_HOOK grammar option. This is a boolean option. No
nodeusesparser Sets the NODE_USES_PARSER grammar option. This is a boolean option. No
static Sets the STATIC grammar option. This is a boolean option. No
visitor Sets the VISITOR grammar option. This is a boolean option. No
nodepackage Sets the NODE_PACKAGE grammar option. This is a string option. No
visitorexception Sets the VISITOR_EXCEPTION grammar option. This is a string option. No
nodeprefix Sets the NODE_PREFIX grammar option. This is a string option. No
maxmemory Max amount of memory to allocate to the forked JVM. since Ant 1.8.3 No

Example

Invoke JJTree on grammar file src/Parser.jjt, writing the generated grammar file, Parser.jj, to build/src. The grammar option NODE_USES_PARSER is set to true when invoking JJTree.

<jjtree target="src/Parser.jjt"
        outputdirectory="build/src"
        javacchome="c:/program files/JavaCC"
        nodeusesparser="true"/>

Comparison of output locations between command line JJTree and different Ant taskdef versions

Command line JJTree options and generated files (working directory: /tmp) Ant 1.5.3 versus command line Ant 1.6 versus command line 
jjtree  grammar.jjt
    /tmp/grammar.jj
    /tmp/<generated>.java
 Same Same 
jjtree  relative/grammar.jjt
    /tmp/grammar.jj
    /tmp/<generated>.java
 
/tmp/relative/grammar.jj
/tmp/relative/<generated>.java
 Same 
jjtree /tmp/absolute/grammar.jjt
    /tmp/grammar.jj
    /tmp/<generated>.java
 
/tmp/absolute/grammar.jj
/tmp/absolute/<generated>.java
 Same 
jjtree -OUTPUT_DIRECTORY:relative grammar.jjt
    /tmp/relative/grammar.jj
    /tmp/relative/<generated>.java
 Same Same 
jjtree -OUTPUT_DIRECTORY:relative relative/grammar.jjt
    /tmp/relative/grammar.jj
    /tmp/relative/<generated>.java
 Same Same 
jjtree -OUTPUT_DIRECTORY:relative /tmp/absolute/grammar.jjt
    /tmp/relative/grammar.jj
    /tmp/relative/<generated>.java
 Same Same 
jjtree -OUTPUT_DIRECTORY:/tmp/absolute/ grammar.jjt
    /tmp/absolute/grammar.jj
    /tmp/absolute/<generated>.java
 Same Same 
jjtree -OUTPUT_DIRECTORY:/tmp/absolute/ relative/grammar.jjt
    /tmp/absolute/grammar.jj
    /tmp/absolute/<generated>.java
 Same Same 
jjtree -OUTPUT_DIRECTORY:/tmp/absolute/ /tmp/absolute/grammar.jjt
    /tmp/absolute/grammar.jj
    /tmp/absolute/<generated>.java
 Same Same 
jjtree -OUTPUT_FILE:output.jj grammar.jjt
    /tmp/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj relative/grammar.jjt
    /tmp/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj /tmp/absolute/grammar.jjt
    /tmp/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:relative grammar.jjt
    /tmp/relative/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:relative relative/grammar.jjt
    /tmp/relative/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:relative /tmp/absolute/grammar.jjt
    /tmp/relative/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ grammar.jjt
    /tmp/absolute/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ relative/grammar.jjt
    /tmp/absolute/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ /tmp/absolute/grammar.jjt
    /tmp/absolute/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj relative/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj /tmp/absolute/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:relative grammar.jjt
    /tmp/relative/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:relative relative/grammar.jjt
    /tmp/relative/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:relative /tmp/absolute/grammar.jjt
    /tmp/relative/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ grammar.jjt
    /tmp/absolute/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ relative/grammar.jjt
    /tmp/absolute/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ /tmp/absolute/grammar.jjt
    /tmp/absolute/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj relative/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj /tmp/absolute/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:D:/tmp/subdir/output.jj grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Not Supported* 
jjtree -OUTPUT_FILE:D:/tmp/subdir/output.jj relative/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Not Supported* 
jjtree -OUTPUT_FILE:D:/tmp/subdir/output.jj /tmp/absolute/grammar.jjt
    /tmp/subdir/output.jj
    /tmp/<generated>.java
 Not Supported Not Supported* 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:relative grammar.jjt
    /tmp/relative/tmp/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:relative relative/grammar.jjt
    /tmp/relative/tmp/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:relative /tmp/absolute/grammar.jjt
    /tmp/relative/tmp/subdir/output.jj
    /tmp/relative/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ grammar.jjt
    /tmp/absolute/tmp/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ relative/grammar.jjt
    /tmp/absolute/tmp/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same 
jjtree -OUTPUT_FILE:/tmp/subdir/output.jj -OUTPUT_DIRECTORY:/tmp/absolute/ /tmp/absolute/grammar.jjt
    /tmp/absolute/tmp/subdir/output.jj
    /tmp/absolute/<generated>.java
 Not Supported Same

Note: When running JJTree with the Ant taskdef jjtree the option -OUTPUT_DIRECTORY must always be set, because the project's basedir and the Ant working directory might differ. So even if you don't specify the outputdirectory for taskdef jjtree, JJTree will be called with the -OUTPUT_DIRECTORY set to the project's basedir. But when the -OUTPUT_DIRECTORY is set, the -OUTPUT_FILE setting is handled as if relative to this -OUTPUT_DIRECTORY. Thus when the -OUTPUT_FILE is absolute or contains a drive letter we have a problem. Therefore absolute outputfiles (when the outputdirectory isn't specified) are made relative to the default directory. And for this reason outputfiles that contain a drive letter can't be supported.

By the way: specifying a drive letter in the -OUTPUT_FILE when the -OUTPUT_DIRECTORY is set, also results in strange behavior when running JJTree from the command line.