for (PropertyVisitor visitor : visitors) {
            visitor.visitInputProperty(propertyName, value, optional);
        }
    }

    @Override
    public void visitOutputFileProperty(String propertyName, boolean optional, PropertyValue value, OutputFilePropertyType filePropertyType) {
        for (PropertyVisitor visitor : visitors) {

    private final List<DependencyGraphVisitor> visitors;

    public CompositeDependencyGraphVisitor(List<DependencyGraphVisitor> visitors) {
        this.visitors = visitors;
    }

    @Override
    public void start(RootGraphNode root) {
        for (DependencyGraphVisitor visitor : visitors) {
            visitor.start(root);
        }
    }

    @Override

    private final List<DependencyArtifactsVisitor> visitors;

    public CompositeDependencyArtifactsVisitor(List<DependencyArtifactsVisitor> visitors) {
        this.visitors = visitors;
    }

    @Override
    public void visitNode(DependencyGraphNode node) {
        for (DependencyArtifactsVisitor visitor : visitors) {
            visitor.visitNode(node);
        }
    }

    @Override

        buildOpResult.visitInputFileProperties(visitor)

        then:
        1 * visitor.preProperty(_)
        1 * visitor.preRoot(_)

        and:
        1 * visitor.preDirectory { it.path == '/foo' }

        and:
        1 * visitor.file() { it.path == '/foo/one.txt' }

        and:
        1 * visitor.preDirectory { it.path == '/foo/sub' }

        and:
        1 * visitor.file() { it.path == '/foo/sub/two.txt' }

        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 * _
    }

// Visitor is called with each object name, and returns true if visiting should continue
type Visitor func(name string) (shouldContinue bool)

func skipEmptyNames(visitor Visitor) Visitor {
	return func(name string) bool {
		if len(name) == 0 {
			// continue visiting
			return true
		}
		// delegate to visitor
		return visitor(name)
	}
}

        when:
        visitor.visitNode(rootNode)

        then:
        2 * rootNode.owner >> component
        1 * rootNode.root >> true
        1 * component.componentId >> identifier
        1 * component.metadataOrNull >> null

        and:
        visitor.allResolvedModules.empty
    }

    def 'finishes without error when visited match expected'() {
        given:

        /**
         * The visited value is attached to the given location.
         */
        void visitExact(T value);

        /**
         * The visited value is an ancestor of the visited location
         */
        void visitAncestor(T value, VfsRelativePath pathToVisitedLocation);

        /**
         * The visited value is a child of the visited location.
         *

        0 * visitor._
    }

    def "visits files of directory tree"() {
        def visitor = Mock(ClasspathEntryVisitor)

        def dir = tmpDir.createDir("dir")
        dir.file("empty").createDir()
        dir.file("a.class").text = "a"
        dir.file("a/b/c.class").text = "c"
        dir.file("a/b/empty").createDir()

        when:
        walker.visit(dir, visitor)

        then:

        Map<String, File> visited = [:]
        FileVisitor visitor = [
                visitFile: {FileVisitDetails details ->
                    visited.put(details.path, details.file)
                },
                visitDir: {FileVisitDetails details ->
                }
        ] as FileVisitor

        tree.visit(visitor)

        assertThat(visited, equalTo(files))
    }