}
    }

    public boolean hasFilters() {
        return transformers.hasTransformers();
    }

    public void add(Class<? extends FilterReader> filterType) {
        add(filterType, null);
    }

    public void add(final Class<? extends FilterReader> filterType, final Map<String, ?> properties) {
        transformers.add(new Transformer<Reader, Reader>() {
            @Override

        return this;
    }

    @Override
    public ContentFilterable filter(Map<String, ?> properties, Class<? extends FilterReader> filterType) {
        filterChain.add(filterType, properties);
        return this;
    }

    @Override
    public ContentFilterable filter(Class<? extends FilterReader> filterType) {
        filterChain.add(filterType);
        return this;
    }

    @Override

    }

    @Override
    public CopySpec filter(Map<String, ?> properties, Class<? extends FilterReader> filterType) {
        return getDelegateCopySpec().filter(properties, filterType);
    }

    @Override
    public CopySpec filter(Class<? extends FilterReader> filterType) {
        return getDelegateCopySpec().filter(filterType);
    }

    @Override

        return this;
    }

    @Override
    public CopySpec filter(Map<String, ?> properties, Class<? extends FilterReader> filterType) {
        delegate.filter(properties, filterType);
        return this;
    }

    @Override
    public CopySpec filter(Class<? extends FilterReader> filterType) {
        delegate.filter(filterType);
        return this;
    }

    @Override

        }

        @Override
        public ContentFilterable filter(Map<String, ?> properties, Class<? extends FilterReader> filterType) {
            throw new UnsupportedOperationException();
        }

        @Override
        public ContentFilterable filter(Class<? extends FilterReader> filterType) {
            throw new UnsupportedOperationException();
        }

        @Override

        }
    }

    private static class TypeBackedFilterAction implements Action<FileCopyDetails> {
        private final Class<? extends FilterReader> filterType;

        public TypeBackedFilterAction(Class<? extends FilterReader> filterType) {
            this.filterType = filterType;
        }

        @Override
        public void execute(FileCopyDetails fileCopyDetails) {

     */
    @Override
    public AbstractCopyTask filter(Map<String, ?> properties, Class<? extends FilterReader> filterType) {
        getMainSpec().filter(properties, filterType);
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public AbstractCopyTask filter(Class<? extends FilterReader> filterType) {
        getMainSpec().filter(filterType);
        return this;
    }

import java.io.File;
import java.io.FileReader;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;

/**
 * Deeply opinionated file filter that adds elements to the release notes HTML page.
 */
public class ReleaseNotesTransformer extends FilterReader {
    private File baseCss;

erpolation; public abstract interface ValueSource { public abstract Object getValue(String); } org/codehaus/plexus/util/InterpolationFilterR.class package org.codehaus.plexus.util; public synchronized class InterpolationFilterR extends java.io.FilterReader { private String replaceData; private int replaceIndex; private java.util.Map variables; private String beginToken; private String endToken; private int beginTokenLength; private int endTokenLength; private static String DEFAULT_BEGIN_TOKEN; private...

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