JFSQL (Java File System Query Language) is a Java library for querying the file system. This library provide a query language to allow external uses for exemple as shell command.

For linux :

./build.sh

Usage :

java -jar jfsql.jar "<query>"

TODO maven dependncy

Query query = Queryfactory.newQuery("get file in('/home/Bob')");
List<Comparable> results = query.execute();

General syntax :

GET [<limit>] [<distinct>] <attribute> IN (<path> [DEEP <positiveNumber>] [, <path> [DEEP <positiveNumber>]]*) [HAVING <conditions>] [SORT BY <property> ASCENDING | DESCENDING];

Select the file attribute to return as a result of the query.

• file : select the Java File object or full file or directory name (path + name)
• name : get the name of files or directories
• owner : get the owner of files or directories
• path : get the path
• parent : get the parent name
• size : get the size (byte)
• content : select the content (only on files)
• last_update_date : get the last modification date (yyyy/mm/dd hh/mm/ss)
• last_access_date : get the last access date (yyyy/mm/dd hh/mm/ss)
• creation_date : get the creation date (yyyy/mm/dd hh/mm/ss)
• status : 'unaccessible', 'readable', 'writable', 'executable'
• type : 'file' or 'directory'

You can limit the number of results.

get 10 file in ('.');

This query return the first ten files in the current directory.

If the distinct key word is specified, the query ensure that the result contains no doubles values.

get distrinct name in ('.');

Get files or directories names with no double values.

Sepcify with directories the query has to walk. Paths must be absolutes.

get file in ('/home/Bob');

List all files or directories recursivly in Bob's home folder

You can specify as many locations as you want like so :

get file in ('/home/Bob', '/home/Jane', '/home/William');

Instead of write the full path, you can specify the current directory by '.'

get file in ('.');

List all files in current directory

By default, jfsql search for files recursivly (all sub folder will be walked). It's possible to limit the depth like this :

get file in ('/' deep 1);

List all elements in the root (sub directories are not read) Of course, you can specify the deep clause by folder :

get file in ('/opt' deep 1, '/home' deep 2);

This clause specify with kind of file or directory the query can select (This part look like where SQL clause).

Exemple :

get file int ('.') having size > 0;

Get all files in the current directory with a size greather than 0

You can filter on followings properties :

• name : name of the file or the directory
• owner : the owner of the file or the directory
• path : the path
• parent : the parent name
• size : the size in bytes (directory size is not the size of directory's content but the size of the directory without any content)
• content : the content (only on files)
• last_update_date : the last modification date (yyyy/mm/dd hh/mm/ss)
• last_access_date : the last access date (yyyy/mm/dd hh/mm/ss)
• creation_date : the creation date (yyyy/mm/dd hh/mm/ss)
• status : 'unaccessible', 'readable', 'writable', 'executable'
• type : 'file' or 'directory', hidden

Note : for type ans status property, is operator is safer than others

Supported comparators :

• =
• <>
• >=
• <
• <=
• in : some values fix values
• like : true if the property contains the specifier string (only on text)
• between : test if the property is between the two specified values (works on all types but became unstable on texts)
• match true if the property match the specified regex. (only on text)

Exemples :

path = '/home'
size > 0
creation_date between '2014/01/01 00:00:00' and '2014/12/31 23:59:59'
parent in ('parent 1', 'parent 2', 'parent 3')
content like 'dolor sit'
name match '^.*[0-9]{2}-[0-9]{2}-[0-9]{4}.*$' // the file name must contain a date like "27-02-2015"

Supported logical operators :

• and
• or
• not

Complex query exemple :

get content in ('.') having parent = 'logs' or (size > 0 and name like '.log') and type = 'file';

Having clause also support sub queries :

get file in ('/' deep 1) having type = 'file' and size = get 1 size in ('/' deep 1) having type = 'file' sort by size descending;

Get the bigest file in root with sub query. Of course, this exemple can be written differently by doing :

get 1 file in ('/' deep 1) having type = 'file' sort by size descending;

Simple clause for sorting query result by a specific property.

get file in ('.') sort by name ascending;

Get all files in current directory in alphabetic order

You can sort on followings properties :

• name : name of the file or the directory
• owner : the owner of the file or the directory
• path : the path
• parent : the parent name
• size : the size in bytes (directory size is not the size of directory's content but the size of the directory without any content)
• content : the content (only on files)
• last_update_date : the last modification date (yyyy/mm/dd hh/mm/ss)
• last_access_date : the last access date (yyyy/mm/dd hh/mm/ss)
• creation_date : the creation date (yyyy/mm/dd hh/mm/ss)

Sort not working well for status as type property

Aggregations functions is only supported in get clause :

• count (attribute)
• min (attribute) : works only on numbers
• max (attribute) : works only on numbers
• avg (attribute) : works only on numbers
• sum (attribute) : works only on numbers

// Standalone usage
count(1, 2, 3, 4);
// Output -> 4

// Query usage
count(get file in('/'));

Those functions can be use in get or having clauses :

• asDate (value) : parse the specified value and return a date
• asInteger (value) : convert the specified value as an java Integer type
• asDouble (value) : convert the specified value as a java Double type
• asString (value) : convert the value as string
• asDateString(value, formatPattern) : format the specified date with the specified format as string. You have to use Java date formatting (see this link)
• concat(string, string[, string]*) : concat as many strings as you want
• extract (string, regexp) : return the first substring matches in the specified regular expression

concat('Ogama''s home size : ', sum(get size in('/home/ogama' deep 1)), ' bytes');

// Output -> Ogama's home size : 286306.0 bytes
// Note you can escape the quote by writing double quote