org.apache.maven.shared.utils.io
Class DirectoryScanner

java.lang.Object
  org.apache.maven.shared.utils.io.DirectoryScanner

public class DirectoryScanner
extends Object

Class for scanning a directory for files/directories which match certain criteria.

These criteria consist of selectors and patterns which have been specified. With the selectors you can select which files you want to have included. Files which are not selected are excluded. With patterns you can include or exclude files based on their filename.

The idea is simple. A given directory is recursively scanned for all files and directories. Each file/directory is matched against a set of selectors, including special support for matching against filenames with include and and exclude patterns. Only files/directories which match at least one pattern of the include pattern list or other file selector, and don't match any pattern of the exclude pattern list or fail to match against a required selector will be placed in the list of files/directories found.

When no list of include patterns is supplied, "**" will be used, which means that everything will be matched. When no list of exclude patterns is supplied, an empty list is used, such that nothing will be excluded. When no selectors are supplied, none are applied.

The filename pattern matching is done as follows: The name to be matched is split up in path segments. A path segment is the name of a directory or file, which is bounded by File.separator ('/' under UNIX, '\' under Windows). For example, "abc/def/ghi/xyz.java" is split up in the segments "abc", "def","ghi" and "xyz.java". The same is done for the pattern against which should be matched.

The segments of the name and the pattern are then matched against each other. When '**' is used for a path segment in the pattern, it matches zero or more path segments of the name.

There is a special case regarding the use of File.separators at the beginning of the pattern and the string to match:
When a pattern starts with a File.separator, the string to match must also start with a File.separator. When a pattern does not start with a File.separator, the string to match may not start with a File.separator. When one of these rules is not obeyed, the string will not match.

When a name path segment is matched against a pattern path segment, the following special characters can be used:
'*' matches zero or more characters
'?' matches one character.

Examples:

"**\*.class" matches all .class files/dirs in a directory tree.

"test\a??.java" matches all files/dirs which start with an 'a', then two more characters and then ".java", in a directory called test.

"**" matches everything in a directory tree.

"**\test\**\XYZ*" matches all files/dirs which start with "XYZ" and where there is a parent directory called test (e.g. "abc\test\def\ghi\XYZ123").

Case sensitivity may be turned off if necessary. By default, it is turned on.

Example of usage:

 String[] includes = { "*\*\*.class" };
 String[] excludes = { "modules\\\*\**" };
 ds.setIncludes( includes );
 ds.setExcludes( excludes );
 ds.setBasedir( new File( "test" ) );
 ds.setCaseSensitive( true );
 ds.scan();

 System.out.println( "FILES:" );
 String[] files = ds.getIncludedFiles();
 for ( int i = 0; i < files.length; i++ )
 {
     System.out.println( files[i] );
 }
 

This will scan a directory called test for .class files, but excludes all files in all proper subdirectories of a directory called "modules"

This class must not be used from multiple Threads concurrently!

Author:

Arnout J. Kuiper ajkuiper@wxs.nl, Magesh Umasankar, Bruce Atherton, Antoine Levy-Lambert

DEFAULTEXCLUDES

public static final String[] DEFAULTEXCLUDES

Patterns which should be excluded by default.

See Also:

addDefaultExcludes()

DirectoryScanner

public DirectoryScanner()

Sole constructor.

setBasedir

public void setBasedir(String basedir)

Sets the base directory to be scanned. This is the directory which is scanned recursively. All '/' and '\' characters are replaced by File.separatorChar, so the separator used need not match File.separatorChar.

Parameters:

basedir - The base directory to scan. Must not be null.

setBasedir

public void setBasedir(@Nonnull
                       File basedir)

Sets the base directory to be scanned. This is the directory which is scanned recursively.

Parameters:

basedir - The base directory for scanning. Should not be null.

getBasedir

public File getBasedir()

Returns the base directory to be scanned. This is the directory which is scanned recursively.

Returns:

the base directory to be scanned

setCaseSensitive

public void setCaseSensitive(boolean isCaseSensitive)

Sets whether or not the file system should be regarded as case sensitive.

Parameters:

isCaseSensitive - whether or not the file system should be regarded as a case sensitive one

setFollowSymlinks

public void setFollowSymlinks(boolean followSymlinks)

Sets whether or not symbolic links should be followed.

Parameters:

followSymlinks - whether or not symbolic links should be followed

setIncludes

public void setIncludes(String... includes)

Sets the list of include patterns to use. All '/' and '\' characters are replaced by File.separatorChar, so the separator used need not match File.separatorChar.

When a pattern ends with a '/' or '\', "**" is appended.

Parameters:

includes - A list of include patterns. May be null, indicating that all files should be included. If a non-null list is given, all elements must be non-null.

setExcludes

public void setExcludes(String... excludes)

Sets the list of exclude patterns to use. All '/' and '\' characters are replaced by File.separatorChar, so the separator used need not match File.separatorChar.

When a pattern ends with a '/' or '\', "**" is appended.

Parameters:

excludes - A list of exclude patterns. May be null, indicating that no files should be excluded. If a non-null list is given, all elements must be non-null.

setScanConductor

public void setScanConductor(ScanConductor scanConductor)

scan

public void scan()
          throws IllegalStateException

Scans the base directory for files which match at least one include pattern and don't match any exclude patterns. If there are selectors then the files must pass muster there, as well.

Throws:

IllegalStateException - if the base directory was set incorrectly (i.e. if it is null, doesn't exist, or isn't a directory).

diffIncludedFiles

public DirectoryScanResult diffIncludedFiles(String... oldFiles)

Determine the file differences between the currently included files and a previously captured list of files. This method will not look for a changed in content but sole in the list of files given.

The method will compare the given array of file Strings with the result of the last directory scan. It will execute a scan() if no result of a previous scan could be found.

The result of the diff can be queried by the methods DirectoryScanResult.getFilesAdded() and DirectoryScanResult.getFilesRemoved()

Parameters:

oldFiles - the list of previously captured files names.

diffFiles

public static DirectoryScanResult diffFiles(@Nullable
                                            String[] oldFiles,
                                            @Nullable
                                            String[] newFiles)

getIncludedFiles

public String[] getIncludedFiles()

Returns the names of the files which matched at least one of the include patterns and none of the exclude patterns. The names are relative to the base directory.

Returns:

the names of the files which matched at least one of the include patterns and none of the exclude patterns. May also contain symbolic links to files.

getNotIncludedFiles

public String[] getNotIncludedFiles()

Returns the names of the files which matched none of the include patterns. The names are relative to the base directory. This involves performing a slow scan if one has not already been completed.

Returns:

the names of the files which matched none of the include patterns.

See Also:

slowScan()

getExcludedFiles

public String[] getExcludedFiles()

Returns the names of the files which matched at least one of the include patterns and at least one of the exclude patterns. The names are relative to the base directory. This involves performing a slow scan if one has not already been completed.

Returns:

the names of the files which matched at least one of the include patterns and at at least one of the exclude patterns.

See Also:

slowScan()

getIncludedDirectories

public String[] getIncludedDirectories()

Returns the names of the directories which matched at least one of the include patterns and none of the exclude patterns. The names are relative to the base directory.

Returns:

the names of the directories which matched at least one of the include patterns and none of the exclude patterns. May also contain symbolic links to directories.

getNotIncludedDirectories

public String[] getNotIncludedDirectories()

Returns the names of the directories which matched none of the include patterns. The names are relative to the base directory. This involves performing a slow scan if one has not already been completed.

Returns:

the names of the directories which matched none of the include patterns.

See Also:

slowScan()

getExcludedDirectories

public String[] getExcludedDirectories()

Returns the names of the directories which matched at least one of the include patterns and at least one of the exclude patterns. The names are relative to the base directory. This involves performing a slow scan if one has not already been completed.

Returns:

the names of the directories which matched at least one of the include patterns and at least one of the exclude patterns.

See Also:

slowScan()

addDefaultExcludes

public void addDefaultExcludes()

Adds default exclusions to the current exclusions set.