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 Apache Ant 1.5.2, resources are available for explicit use since Ant 1.7.

### Built-in resource types

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.
- javaconstant—a constant in a class loadable via a Java classloader.
- propertyresource—an Ant property.
- string—a text string.
- tarentry—an entry in a tar file.
- url—a URL.
- xzresource—an XZ compressed resource.
- 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
parentFirst | Whether to consult the parent classloader first—the parent classloader most likely is the system classloader—when using a nested classpath. Since Ant 1.8.0 | No; defaults to true

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

#### javaconstant

Loads the value of a Java constant. As a specialisation of javaresource all of its attributes and nested elements are supported. A constant must be specified as `public static` otherwise it could not be loaded.

Attribute | Description | Required
--- | --- | ---
name | The name of the resource. Must be specified as full qualified field name. | Yes

##### Examples

This loads the value of the constant `VERSION` of the `org.acme.Main` class into the version-property. The classpath for finding that class is provided via nested `classpath` element.

    <loadresource property="version">
      <javaconstant name="org.acme.Main.VERSION">
        <classpath>
          <pathelement location="${acme.lib.dir}"/>
        </classpath>
      </javaconstant>
    </loadresource>

Create a new file `c:/temp/org.apache.tools.ant.Main.DEFAULT_BUILD_FILENAME` with the content of that constant (build.xml).

    <copy todir="c:/temp">
      <javaconstant name="org.apache.tools.ant.Main.DEFAULT_BUILD_FILENAME"/>
    </copy>

#### 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 | The zip file containing this resource | Yes, unless a nested resource collection has been specified
archive | alias of zipfile
name | The name of the archived resource | Yes
encoding | The encoding of the zipfile | No; defaults to default JVM character encoding

#### 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

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.

#### xzresource

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.

XZ compression support has been added since Apache Ant 1.10.1 and depends on external libraries not included in the Ant distribution. See Library Dependencies for more information.

#### 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
baseUrl | The base URL which must be combined with relativePath
relativePath | Relative path that defines the URL when combined with baseUrl | If using baseUrl

#### string

Represents a Java String. It can be written to, but only once, after which it will be an error to write to again.

Attribute | Description | Required
--- | --- | ---
value | The value of this resource | No

The resource also supports nested text, which can only be supplied if the value attribute is unset:

    <string>
        self.log("Ant version =${ant.version}");
    </string>

#### 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, multirootfileset, 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

Strangely, some tasks can even legitimately behave as resource collections:

- concat exposes a concatenated resource, and adds e.g. filtering to Ant's resource-related capabilities.

### Additional built-in resource collections

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
- last—last n resources from a nested collection
- allbutfirst—all except the first n resources from a nested collection
- allbutlast—all except the last 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
- mappedresources—generic resource collection wrapper that maps the names of the nested resources using a mapper.
- archives—wraps around different resource collections and treats the nested resources as ZIP or TAR archives that will be extracted on the fly.
- resourcelist—a collection of resources whose names have been read from another resource.

#### 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).

Attribute | Description | Required
--- | --- | ---
cache | Whether to cache results. since Ant 1.8.0 | No; default false

#### 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 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 | Name of a file; each line of this file is taken to be an include pattern.
excludes | Comma- or space-separated list of patterns of files that must be excluded | No; defaults to default excludes or none if defaultexcludes is no
excludesfile | Name of a file; each line of this file is taken to be an exclude pattern.
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 a 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, combined via a logical AND. 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.
- readable—select files (resources must be files) if they are readable.
- writable—select files (resources must be files) if they are writable.

##### name

Selects resources by name.

Attribute | Description | Required
--- | --- | ---
name | The name pattern to test using standard Ant patterns. | Exactly one of the two
regex | The regular expression matching files to select.
casesensitive | Whether name comparisons are case-sensitive | No; default true
handledirsep | If this is specified, the mapper will treat a \ character in a resource name or name attribute as a / for the purposes of matching. This attribute can be true or false. Since Ant 1.8.0 | No; default false

##### 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 using the current locale | No; default is MM/dd/yyyy hh:mm a using the US locale
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, any (since Ant 1.8) | 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

Assuming the namespace settings

    rsel="antlib:org.apache.tools.ant.types.resources.selectors"
    rcmp="antlib:org.apache.tools.ant.types.resources.comparators"

    <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>

Selects files `a`, `b`, `c`, and `d`.

    <project rsel="antlib:org.apache.tools.ant.types.resources.selectors">
        <macrodef name="copyFromPath">
            <attribute name="todir"/>
            <attribute name="refid"/>
            <element name="nested-resource-selectors" optional="yes" implicit="true"/>
            <sequential>
                <mkdir dir="@{todir}" taskname="copyFromPath"/>
                <copy todir="@{todir}" taskname="copyFromPath">
                    <restrict>
                        <path refid="@{refid}"/>
                        <rsel:or>
                            <nested-resource-selectors/>
                        </rsel:or>
                    </restrict>
                    <flattenmapper/>
                </copy>
            </sequential>
        </macrodef>
        <copyFromPath refid="classpath" todir="todir">
            <rsel:name name="log4j.properties"/>
            <rsel:name name="default.properties"/>
        </copyFromPath>
    </project>

Creates the `todir` directory and copies (if present) the files `log4j.properties` and `default.properties` from the classpath (already used while compiling).

    <project>
        <filelist id="allfiles" dir="${ant.home}/bin" files="ant.cmd,foo.txt,ant.bat,bar.txt,ant"/>
        <restrict id="missingfiles">
            <filelist refid="allfiles"/>
            <rsel:not xmlns:rsel="antlib:org.apache.tools.ant.types.resources.selectors">
                <rsel:exists/>
            </rsel:not>
        </restrict>
        <echo>These files are missed: ${toString:missingfiles}</echo>
    </project>

The resource collection allfiles defines a list of files which are expected. The restrict missingfiles uses the `<not><exists>` selector for getting all files which are not present. Finally we use the `toString:` pathshortcut for getting them in a readable form: `[echo] These files are missed: ....foo.txt;....bar.txt`

#### sort

Sorts a 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.

##### Examples

    <property name="eol" value="${line.separator}"/>
    <pathconvert property="sorted" pathsep="${eol}">
      <sort>
        <tokens>
          <string value="foo bar etc baz"/>
          <stringtokenizer/>
        </tokens>
      </sort>
    </pathconvert>

The resource of type string foo bar etc baz is split into four tokens by the `stringtokenizer`. These tokens are sorted and there `sorted` gets the value of bar baz etc foo.

    <sort>
      <fileset dir="foo"/>
      <reverse xmlns="antlib:org.apache.tools.ant.types.resources.comparators">
        <date/>
      </reverse>
    </sort>

This takes all files from `foo` and sorts them by modification date in reverse order. Because the resource comparators used (`<reverse>` and `<date>`) are in an internal antlib their namespace must be set explicitly.

#### 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.

#### last

Since Ant 1.7.1

Includes the last count resources from a nested resource collection. This can be used in conjunction with the sort collection, for example, to select the last 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.

#### allbutfirst

Since Ant 1.9.5

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

Attribute | Description | Required
--- | --- | ---
count | The number of resources to exclude | 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.

#### allbutlast

Since Ant 1.9.5

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

Attribute | Description | Required
--- | --- | ---
count | The number of resources to exclude | 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. 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 default JVM character encoding
cache | Whether to cache results; disabling may seriously impact performance | No; default true

##### Parameters specified as nested elements

- A single resource collection is required.
- One nested tokenizer may be specified. If omitted, a LineTokenizer will be used.

##### Examples

    <concat>
      <union>
        <sort>
          <tokens>
            <resources refid="input"/>
            <linetokenizer includedelims="true"/>
          </tokens>
        </sort>
      </union>
    </concat>

Implements Unix `sort -u` against resource collection input.

#### 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

##### Examples

    <resources id="A">
        <string value="a"/>
        <string value="b"/>
    </resources>
    <resources id="B">
        <string value="b"/>
        <string value="c"/>
    </resources>
    <union id="union"><resources refid="A"/><resources refid="B"/></union>
    <intersect id="intersect"><resources refid="A"/><resources refid="B"/></intersect>
    <difference id="difference"><resources refid="A"/><resources refid="B"/></difference>
    <echo>
      A: ${toString:A}                    = a;b
      B: ${toString:B}                    = b;c

      union     : ${toString:union}       = a;b;c
      intersect : ${toString:intersect}   = b
      difference: ${toString:difference}  = a;c
    </echo>

#### mappedresources

Since Ant 1.8.0

Wraps another resource collection and maps the names of the nested resources using a mapper.

Even if mappedresources wraps a resource collection that consists of file-system based resources, mappedresources will not appear to be file-system based. This means you can't use mappedresources with tasks that only allow file-system based resources.

##### Parameters specified as attributes

Attribute | Description | Required
--- | --- | ---
cache | Whether to cache results; enabling may improve performance. Since Ant 1.8.1 | No; default false
enablemultiplemappings | If true the collection will use all the mappings for a given source path. If false it will only process the first resource. since Ant 1.8.1 | No; defaults to false

##### Parameters specified as nested elements

A single resource collection is required.

A single mapper can be used to map names. If no mapper has been given (which doesn't make any sense, honestly), an identity mapper will be used.

##### Examples

Copies all files from a given directory to a target directory adding `.bak` as an extension. Note this could be done with a `mapper` nested into `copy` directly as well.

    <copy todir="${target}">
      <mappedresources>
        <fileset dir="${src}"/>
        <globmapper from="*" to="*.bak"/>
      </mappedresources>
    </copy>

Creates a WAR archive adding all `CLASSPATH` entries that are files to the `WEB-INF/lib` directory without keeping their files-system structure.

    <war destfile="${output}">
      <mappedresources>
        <restrict>
          <path path="${java.class.path}"/>
          <type type="file"/>
        </restrict>
        <chainedmapper>
          <flattenmapper/>
          <globmapper from="*" to="WEB-INF/lib/*"/>
        </chainedmapper>
      </mappedresources>
    </war>

#### archives

Since Ant 1.8.0

This resource collection accepts an arbitrary number of nested resources and assumes that all those resources must be either ZIP or TAR archives. The resources returned by `<archives>` are the contents of the nested archives.

This resource collection is a generalization of zipgroupfileset which is only supported by the zip family of tasks.

`archives` doesn't support any attributes.

##### Parameters specified as nested elements

`<archives>` has two nested elements `<zips>` and `<tars>` that are unions themselves, i.e. they accept arbitrary many resource(collection)s as nested elements.

The nested resources of `<zips>` are treated as ZIP archives, the nested resources of `<tars>` as TAR archives.

##### Examples

Copies all files from all jars that are on the classpath to `${target}`.

    <copy todir="${target}">
      <archives>
        <zips>
          <restrict>
            <path path="${java.class.path}"/>
            <name name="*.jar"/>
          </restrict>
        </zips>
      </archives>
    </copy>

#### resourcelist

Since Ant 1.8.0

This resource collection accepts an arbitrary number of nested resources, reads those resources and returns a resource for each line read.

If the line contains a colon, Ant will try to use it as an URL and if that fails (or the line doesn't contain a colon) will return a file resource with the line's content as its name.

Properties will be expanded for each line. If the property expansion yields a resource object rather than a string (for example because of custom property helpers), the resources will be returned directly.

`<resourcelist>` is a generalization of `<filelist>`.

Attribute | Description | Required
--- | --- | ---
encoding | The encoding of the nested resources | No; default is default JVM character encoding

##### Parameters specified as nested elements

`<resourcelist>` accepts arbitrary many resource(collection)s as nested elements.

In addition `<resourcelist>` supports nested `<filterchain>` elements that can be used to filter/modify the read resources before their lines get expanded. Such a nested element corresponds to a filterchain.

##### Examples

The following example copies a file from the first URL of several alternatives that can actually be reached. It assumes that the file `mirrors.txt` looks like

        mirrors.txt:
    http://best.mirror.example.org/
    http://second.best.mirror.example.org/mirror/of/best/
    https://yet.another.mirror/
    http://the.original.site/

    <copy todir="${target}">
      <first>
        <restrict>
          <resourcelist>
            <file file="mirrors.txt"/>
          </resourcelist>
          <exists/>
        </restrict>
      </first>
    </copy>