Examines and removes out of date target files. If any of the target files are out of date with respect to any of the source files, all target files are removed. This is useful where dependencies cannot be computed (for example, dynamically interpreted parameters or files that need to stay in synch but are not directly linked) or where the ant task in question could compute them but does not (for example, the linked DTD for an XML file using the XSLT task). nested arguments:

• sources (resource union describing the source resources to examine)
• srcfileset (fileset describing the source files to examine)
• srcfilelist (filelist describing the source files to examine)
• targets (path describing the target files to examine)
• targetfileset (fileset describing the target files to examine)
• targetfilelist (filelist describing the target files to examine)

At least one of both source and target entities is required.

This task will examine each of the sources against each of the target files. If any target files are out of date with respect to any of the sources, all targets are removed. If any sources or targets do not exist, all targets are removed. Hint: If missing files should be ignored, specify them as include patterns in filesets, rather than using filelists.

This task attempts to optimize speed of dependency checking by comparing only the dates of the oldest target file and the newest source.

Example uses:

• Record the fact that an XML file must be up to date with respect to its XSD (Schema file), even though the XML file itself includes no reference to its XSD.
• Record the fact that an XSL stylesheet includes other sub-stylesheets
• Record the fact that java files must be recompiled if the ant build file changes