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".
| Constructor and Description |
|---|
DirectoryScanner() |
DirectoryScanner(Path dir) |
DirectoryScanner(Path dir,
Collection<String> includes) |
DirectoryScanner(Path dir,
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.
|
Path |
getBasedir()
Returns the base directory to be scanned.
|
List<String> |
getIncludes() |
boolean |
isCaseSensitive() |
protected boolean |
isIncluded(String name)
Tests whether or not a name matches against at least one include
pattern.
|
static String |
normalizePattern(String pattern)
Normalizes the pattern, e.g. converts forward and backward slashes to the platform-specific file separator.
|
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. |
Collection<Path> |
scan()
Scans the base directory for files which match at least one include
pattern and don't match any exclude patterns.
|
<C extends Collection<Path>> |
scan(Supplier<? extends C> factory) |
protected <C extends Collection<Path>> |
scandir(Path rootDir,
Path dir,
C filesList)
Scans the given directory for files and directories.
|
void |
setBasedir(Path basedir)
Sets the base directory to be scanned.
|
void |
setCaseSensitive(boolean caseSensitive) |
void |
setIncludes(Collection<String> includes) |
void |
setIncludes(String... includes)
Sets the list of include patterns to use.
|
public DirectoryScanner()
public DirectoryScanner(Path dir)
public DirectoryScanner(Path dir, Collection<String> includes)
public void setBasedir(Path basedir)
basedir - The base directory for scanning.
Should not be null.public Path 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 void setIncludes(Collection<String> includes)
public boolean isCaseSensitive()
public void setCaseSensitive(boolean caseSensitive)
public Collection<Path> scan() throws IOException, IllegalStateException
IllegalStateException - if the base directory was set incorrectly
(i.e. if it is null, doesn't exist, or isn't a directory).IOException - if failed to scan the directory (e.g., access denied)public <C extends Collection<Path>> C scan(Supplier<? extends C> factory) throws IOException, IllegalStateException
IOExceptionIllegalStateExceptionprotected <C extends Collection<Path>> C scandir(Path rootDir, Path dir, C filesList) throws IOException
C - Target matches collection typerootDir - The directory to scan. Must not be null.dir - The path relative to the root directory (needed to prevent
problems with an absolute path when using dir). Must not be null.filesList - Target Collection to accumulate the relative
path matchesIOException - if failed to scan the directoryprotected 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 normalizePattern(String pattern)
pattern - The pattern to normalize, must not be null.null.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 © 2018–2019 The Apache Software Foundation. All rights reserved.