import org.codehaus.plexus.compiler.util.scan.StaleSourceScanner; //导入依赖的package包/类
/**
 * Determines source files to be compiled, based on the SourceMapping. No
 * longer needs to be recursive, since the SourceInclusionScanner handles
 * that.
 * 
 * @param mapping
 * @return
 * @throws MojoExecutionException
 */
protected Set scanSrcDir(final SourceMapping mapping)
		throws MojoExecutionException {
	final int staleMillis = 0;

	final SourceInclusionScanner scanner = new StaleSourceScanner(
			staleMillis);
	scanner.addSourceMapping(mapping);

	try {
		return scanner.getIncludedSources(sourceDirectory, outputDirectory);
	} catch (final InclusionScanException e) {
		throw new MojoExecutionException(
				"Error scanning source root: \'" + sourceDirectory + "\' "
						+ "for stale files to recompile.", e);
	}
}
 

import org.codehaus.plexus.compiler.util.scan.StaleSourceScanner; //导入依赖的package包/类
private Set computeStaleGrammars()
  throws MojoExecutionException
{
  SuffixMapping mapping = new SuffixMapping(".jj", ".jj");
  SuffixMapping mappingCAP = new SuffixMapping(".JJ", ".JJ");

  SourceInclusionScanner scanner = new StaleSourceScanner(staleMillis);

  scanner.addSourceMapping(mapping);
  scanner.addSourceMapping(mappingCAP);

  Set staleSources = new HashSet();

  File sourceDir = new File(sourceDirectory, sourcePath);

  try
  {
    staleSources.addAll(scanner.getIncludedSources(sourceDir, 
                                                   timestampDirectory));
  }
  catch (InclusionScanException e)
  {
    throw new MojoExecutionException("Error scanning source root: \'" + 
                                     sourceDir + 
                                     "\' for stale grammars to reprocess.", 
                                     e);
  }

  return staleSources;
}