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.separator
s
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".
Modifier and Type | Field and Description |
---|---|
protected File |
basedir
The base directory to be scanned.
|
protected List<String> |
filesIncluded
The files which matched at least one include and no excludes
and were selected.
|
protected String[] |
includes
The patterns for the files to be included.
|
protected boolean |
isCaseSensitive
Whether or not the file system should be treated as a case sensitive
one.
|
Constructor and Description |
---|
DirectoryScanner() |
DirectoryScanner(String basedir,
String... includes) |
Modifier and Type | Method and Description |
---|---|
protected boolean |
couldHoldIncluded(String name)
Tests whether or not a name matches the start of at least one include
pattern.
|
File |
getBasedir()
Returns the base directory to be scanned.
|
String[] |
getIncludedFiles()
Returns the names of the files which matched at least one of the
include patterns and none of the exclude patterns.
|
protected boolean |
isIncluded(String name)
Tests whether or not a name matches against at least one include
pattern.
|
static String |
replace(String text,
String repl,
String with,
int max)
Replace a String with another String inside a larger String,
for the first
max values of the search String. |
String[] |
scan()
Scans the base directory for files which match at least one include
pattern and don't match any exclude patterns.
|
protected void |
scandir(File dir,
String vpath)
Scans the given directory for files and directories.
|
void |
setBasedir(File basedir)
Sets the base directory to be scanned.
|
void |
setBasedir(String basedir)
Sets the base directory to be scanned.
|
void |
setIncludes(String[] includes)
Sets the list of include patterns to use.
|
protected File basedir
protected String[] includes
protected List<String> filesIncluded
protected boolean isCaseSensitive
public void setBasedir(String basedir)
File.separatorChar
, so the separator used need not match
File.separatorChar
.basedir
- The base directory to scan.
Must not be null
.public void setBasedir(File basedir)
basedir
- The base directory for scanning.
Should not be null
.public File getBasedir()
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.
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
.public String[] scan() throws IllegalStateException
IllegalStateException
- if the base directory was set
incorrectly (i.e. if it is null
, doesn't exist,
or isn't a directory).protected void scandir(File dir, String vpath)
dir
- The directory to scan. Must not be null
.vpath
- The path relative to the base directory (needed to
prevent problems with an absolute path when using
dir). Must not be null
.public String[] getIncludedFiles()
protected boolean isIncluded(String name)
name
- The name to match. Must not be null
.true
when the name matches against at least one
include pattern, or false
otherwise.protected boolean couldHoldIncluded(String name)
name
- The name to match. Must not be null
.true
when the name matches against the start of at
least one include pattern, or false
otherwise.public static String replace(String text, String repl, String with, int max)
Replace a String with another String inside a larger String,
for the first max
values of the search String.
A null
reference passed to this method is a no-op.
text
- text to search and replace inrepl
- String to search forwith
- String to replace withmax
- maximum number of values to replace, or -1
if no maximumCopyright © 2008–2016 The Apache Software Foundation. All rights reserved.