include::sample[dir="snippets/files/copy/groovy",files="build.gradle[tags=filter-files]"]
====

The `filter()` method has two variants, which behave differently:

* one takes a `{javaApi}/java/io/FilterReader.html[FilterReader]` and is designed to work with Ant filters, such as `ReplaceTokens`
* one takes a closure or link:{javadocPath}/org/gradle/api/Transformer.html[Transformer] that defines the transformation for each line of the source file