import org.gradle.api.tasks.util.PatternSet;

import java.io.File;

/**
 * Used with {@link FileCollectionInternal#visitStructure(FileCollectionStructureVisitor)} this visitor
 * is called for each element in a file collection that is an atomic source of files.
 */
public interface FileCollectionStructureVisitor {
    enum VisitType {
        // Visitor is interested in the contents of the collection
        Visit,

        then:
        1 * source1.visitStructure(_) >> { FileCollectionStructureVisitor visitor -> visitor.visitCollection(null, [dir1]) }
        1 * source2.visitStructure(_) >> { FileCollectionStructureVisitor visitor -> visitor.visitCollection(null, [dir2]) }
        1 * source3.visitStructure(_) >> { FileCollectionStructureVisitor visitor -> visitor.visitCollection(null, [dir3]) }
        0 * _
    }

import org.gradle.api.internal.file.FileCollectionInternal;
import org.gradle.api.internal.file.FileCollectionStructureVisitor;

import java.io.File;
import java.util.LinkedHashSet;
import java.util.Set;

public class ResolvedFileCollectionVisitor implements ResolvedFileVisitor {
    private final FileCollectionStructureVisitor visitor;
    private final Set<File> files = new LinkedHashSet<>();

            // However, currently it is not easy to determine whether this is the case so assume that all transforms
            // have changing inputs
            FileCollectionStructureVisitor.VisitType.NoContents
        } else {
            FileCollectionStructureVisitor.VisitType.Visit
        }
    }

    override fun requireArtifactFiles(): Boolean {
        return true
    }

        if (source is TransformedArtifactSet) {
            // Should only be contained in a ResolutionBackedFileCollection
            throw IllegalArgumentException("Found artifact set $source but was not expecting an artifact set")
        } else {
            FileCollectionStructureVisitor.VisitType.Visit
        }

        }
        failures.add(failure);
    }

    @Override
    public FileCollectionStructureVisitor.VisitType prepareForVisit(FileCollectionInternal.Source source) {
        if (source instanceof LocalDependencyFiles) {
            return FileCollectionStructureVisitor.VisitType.NoContents;
        }
        return FileCollectionStructureVisitor.VisitType.Visit;
    }

    @Override
    public boolean requireArtifactFiles() {

import org.gradle.api.internal.file.FileCollectionInternal;
import org.gradle.api.internal.file.FileCollectionStructureVisitor;

import java.io.File;

public interface ResolvedFileVisitor {
    /**
     * Called prior to scheduling resolution of a set of artifacts. Should be called in result order.
     */
    default FileCollectionStructureVisitor.VisitType prepareForVisit(FileCollectionInternal.Source source) {

        def result = collection.files

        then:
        result.toList() == [file1, file2, file3]

        1 * source1.visitStructure(_) >> { FileCollectionStructureVisitor visitor -> visitor.visitCollection(null, [file1, file2]) }
        1 * source2.visitStructure(_) >> { FileCollectionStructureVisitor visitor -> visitor.visitCollection(null, [file2, file3]) }
        0 * _

        when:
        def result2 = collection.files

        then:

            }
        }

        @Override
        public FileCollectionStructureVisitor.VisitType prepareForVisit(FileCollectionInternal.Source source) {
            if (source instanceof LocalDependencyFiles) {
                return FileCollectionStructureVisitor.VisitType.NoContents;
            }
            return FileCollectionStructureVisitor.VisitType.Visit;
        }

        @Override

public interface ArtifactVisitor {
    /**
     * Called prior to scheduling resolution of a set of artifacts. Should be called in result order.
     */
    default FileCollectionStructureVisitor.VisitType prepareForVisit(FileCollectionInternal.Source source) {
        return FileCollectionStructureVisitor.VisitType.Visit;
    }

    /**