Resources and Resource Collections

Resources

A file-like entity can be abstracted to the concept of a resource. In addition to providing access to file-like attributes, a resource implementation should, when possible, provide the means to read content from and/or write content to the underlying entity. Although the resource concept was introduced in Ant 1.5.2, resources are available for explicit use beginning in Ant 1.7.

The built-in resource types are:

resource - a basic resource.
bzip2resource - a BZip2 compressed resource.
file - a file.
gzipresource - a GZip compressed resource.
javaresource - a resource loadable via a Java classloader.
propertyresource - an Ant property.
string - a text string.
tarentry - an entry in a tar file.
url - a URL.
zipentry - an entry in a zip file.

resource

A basic resource. Other resource types derive from this basic type; as such all its attributes are available, though in most cases irrelevant attributes will be ignored. This and all resource implementations are also usable as single-element Resource Collections.

Attribute	Description	Required
name	The name of this resource	No
exists	Whether this resource exists	No, default true
lastmodified	The last modification time of this resource	No
directory	Whether this resource is directory-like	No, default false
size	The size of this resource	No

file

Represents a file accessible via local filesystem conventions.

Attribute	Description	Required
file	The file represented by this resource	Yes
basedir	The base directory of this resource. When this attribute is set, attempts to access the name of the resource will yield a path relative to this location.	No

javaresource

Represents a resource loadable via a Java classloader.

Attribute	Description	Required
name	The name of the resource.	Yes
classpath	the classpath to use when looking up a resource.	No
classpathref	the classpath to use when looking up a resource, given as reference to a `<path>` defined elsewhere..	No
loaderRef	the name of the loader that is used to load the resource, constructed from the specified classpath.	No

The classpath can also be specified as nested classpath element, where <classpath> is a path-like structure.

zipentry

Represents an entry in a ZIP archive. The archive can be specified using the archive attribute or a nested single-element resource collection. zipentry only supports file system resources as nested elements.

Attribute	Description	Required
zipfile or its alias name archive	The zip file containing this resource	Yes, unless a nested resource collection has been specified.
name	The name of the archived resource	Yes
encoding	The encoding of the zipfile	No; platform default used if unspecified

tarentry

Represents an entry in a TAR archive. The archive can be specified using the archive attribute or a nested single-element resource collection.

Attribute	Description	Required
archive	The tar archive containing this resource	Yes, unless a nested resource collection has been specified.
name	The name of the archived resource	Yes

gzipresource

This is not a stand-alone resource, but a wrapper around another resource providing compression of the resource's contents on the fly. A single element resource collection must be specified as a nested element.

bzip2resource

url

Represents a URL.

Attribute	Description	Required
url	The url to expose	Exactly one of these
file	The file to expose as a file: url

string

Represents a Java String. As such a string is readable but not writable.

Attribute	Description	Required
value	The value of this resource	Yes

propertyresource

Represents an Ant property.

Attribute	Description	Required
name	The property name	Yes

Resource Collections

A Resource Collection is an abstraction of an entity that groups together a number of resources. Several of Ant's "legacy" datatypes have been modified to behave as Resource Collections:

fileset, dirset, filelist, and path (and derivative types) expose file resources
tarfileset can expose file or tarentry resources depending on configuration
zipfileset can expose file or zipentry resources depending on configuration
propertyset exposes property resources

The additional built-in resource collections are:

resources - generic resource collection
files - collection of files similar to fileset
restrict - restrict a resource collection to include only resources meeting specified criteria
sort - sorted resource collection
first - first n resources from a nested collection
tokens - string tokens gathered from a nested collection
union - set union of nested resource collections
intersect - set intersection of nested resource collections
difference - set difference of nested resource collections

resources

A generic resource collection, designed for use with references. For example, if a third-party Ant task generates a Resource Collection of an unknown type, it can still be accessed via a <resources> collection. The secondary use of this collection type is as a container of other resource collections, preserving the order of nested collections as well as duplicate resources (contrast with union).

files

A group of files. These files are matched by absolute patterns taken from a number of PatternSets. These can be specified as nested <patternset> elements. In addition, <files> holds an implicit PatternSet and supports the nested <include>, <includesfile>, <exclude> and <excludesfile> elements of PatternSet directly, as well as PatternSet's attributes.

File Selectors are available as nested elements. A file must be selected by all selectors in order to be included; <files> is thus equivalent to an <and> file selector container.

More simply put, this type is equivalent to a fileset with no base directory. Please note that without a base directory, filesystem scanning is based entirely on include and exclude patterns. A filename (or any) selector can only influence the scanning process after the file has been included based on pattern-based selection.

Attribute	Description	Required
includes	comma- or space-separated list of patterns of files that must be included	At least one of these
includesfile	the name of a file; each line of this file is taken to be an include pattern.	At least one of these
excludes	comma- or space-separated list of patterns of files that must be excluded	No, default none (except default excludes when true)
excludesfile	the name of a file; each line of this file is taken to be an exclude pattern.	No, default none (except default excludes when true)
defaultexcludes	Whether default excludes should be used	No, default true
casesensitive	Whether patterns are case-sensitive	No, default true
followsymlinks	Whether to follow symbolic links (see note below)	No, default true

Note: All files/directories for which the canonical path is different from its path are considered symbolic links. On Unix systems this usually means the file really is a symbolic link but it may lead to false results on other platforms.

restrict

Restricts another nested resource collection using resource selectors:

Attribute Description Required

cache Whether to cache results; disabling may seriously impact performance No, default true

Parameters specified as nested elements

A single resource collection is required.

Nested resource selectors are used to "narrow down" the included resources. These are patterned after file selectors but are, unsurprisingly, targeted to resources. Several built-in resource selectors are available in the internal antlib org.apache.tools.ant.types.resources.selectors:

name - select resources by name.

exists - select existing resources.

date - select resources by date.

type - select resources by type.

size - select resources by size.

instanceof - select resources by class or Ant datatype.

and - "and" nested resource selectors.

or - "or" nested resource selectors.

not - "not" a nested resource selector.

none - select resources selected by no nested resource selectors.

majority - select resources selected by a majority of nested resource selectors.

modified - select resources which content has changed.

contains - select resources containing a particular text string.

containsregexp - select resources whose contents match a particular regular expression.

compare - select resources based on comparison to other resources.

name

Selects resources by name.

Attribute Description Required

name The name pattern to test Yes

casesensitive Whether name comparisons are case-sensitive No, default true

exists

Selects existing resources.

date

Selects resources by date.

Attribute Description Required

millis The comparison date/time in ms since January 1, 1970 One of these

datetime The formatted comparison date/time

pattern SimpleDateFormat-compatible pattern for use with the datetime attribute No, default is "MM/DD/YYYY HH:MM AM_or_PM"

granularity The number of milliseconds leeway to use when comparing file modification times. This is needed because not every file system supports tracking the last modified time to the millisecond level. No; default varies by platform: FAT filesystems = 2 sec; Unix = 1 sec; NTFS = 1 ms.

when One of "before", "after", "equal" No, default "equal"

type

Selects resources by type (file or directory).

Attribute Description Required

type One of "file", "dir" Yes

size

Selects resources by size.

Attribute Description Required

size The size to compare Yes

when One of "equal", "eq", "greater", "gt", "less", "lt", "ge" (greater or equal), "ne" (not equal), "le" (less or equal) No, default "equal"

instanceof

Selects resources by type.

Attribute Description Required

class The class of which the resource must be an instance One of these

type The Ant type that must be assignable from the resource

uri The uri in which type must be defined No

and

Selects a resource if it is selected by all nested resource selectors.

or

Selects a resource if it is selected by at least one nested resource selector.

not

Negates the selection result of the single nested resource selector allowed.

none

Selects a resource if it is selected by no nested resource selectors.

majority

Selects a resource if it is selected by the majority of nested resource selectors.

Attribute Description Required

allowtie Whether a tie (when there is an even number of nested resource selectors) is considered a majority No, default true

compare

Selects a resource based on its comparison to one or more "control" resources using nested resource comparators.

Attribute Description Required

when Comparison ("equal"/"eq", "greater"/"gt", "less"/"lt", "le" (less or equal), "ge" (greater or equal), "ne" (not equal). No, default "equal"

against Quantifier ("all"/"each"/"every", "any"/"some", (exactly) "one", "most"/"majority", "none". No, default "all"

Parameters specified as nested elements

The resources against which comparisons will be made must be specified using the nested <control> element, which denotes a resources collection.

Examples

The following selects files a, b, c, and d:
<restrict>
  <fileset dir="src" includes="a,b,c,d,e,f,g" />
  <rsel:compare when="le" against="all">
    <control>
      <resource name="d" />
    </control>
    <rcmp:name />
  </rsel:compare>
</restrict>

sort

Sorts another nested resource collection according to the resources' natural order, or by one or more nested resource comparators:

Attribute Description Required

cache Whether to cache results; disabling may seriously impact performance No, default true

Parameters specified as nested elements

A single resource collection is required.

The sort can be controlled and customized by specifying one or more resource comparators. Resources can be sorted according to multiple criteria; the first specified is the "outermost", while the last specified is the "innermost". Several built-in resource comparators are available in the internal antlib org.apache.tools.ant.types.resources.comparators:

Resource Comparators:

name - sort resources by name

exists - sort resources by existence

date - sort resources by date

type - sort resources by type

size - sort resources by size

content - sort resources by content

reverse - reverse the natural sort order, or that of a single nested resource comparator

name

Sort resources by name.

exists

Sort resources by existence. Not existing is considered "less than" existing.

date

Sort resources by date.

type

Sort resources by type (file or directory). Because directories contain files, they are considered "greater".

size

Sort resources by size.

content

Sort resources by content.

Attribute Description Required

binary Whether content should be compared in binary mode. If false, content will be compared without regard to platform-specific line-ending conventions. No, default true

reverse

Reverse the natural sort order, or that of a single nested comparator.

first

Includes the first count resources from a nested resource collection. This can be used in conjunction with the sort collection, for example, to select the first few oldest, largest, etc. resources from a larger collection.

Attribute Description Required

count The number of resources to include No, default 1

cache Whether to cache results; disabling may seriously impact performance No, default true

Parameters specified as nested elements

A single resource collection is required.

tokens

Includes the string tokens gathered from a nested resource collection. Uses the same tokenizers supported by the TokenFilter. Hint: imaginative use of this resource collection can implement equivalents for such Unix functions as sort, grep -c, wc and wc -l.

Attribute Description Required

encoding The encoding of the nested resources No, default is platform default

cache Whether to cache results; disabling may seriously impact performance No, default true

Parameters specified as nested elements

A single resource collection is required.

Set operations

The following resource collections implement set operations:

union

intersect

difference

union

Union of nested resource collections.

intersect

Intersection of nested resource collections.

difference

Difference of nested resource collections.

The following attributes apply to all set-operation resource collections:

Attribute Description Required

cache Whether to cache results; disabling may seriously impact performance No, default true