--- /dev/null
+/*******************************************************************************
+ * Copyright (c) 2010, 2014 Sonatype, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * Sonatype, Inc. - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.aether.collection;
+
+import org.eclipse.aether.RepositoryException;
+import org.eclipse.aether.graph.DependencyNode;
+
+/**
+ * Transforms a given dependency graph.
+ * <p>
+ * <strong>Note:</strong> Implementations must be stateless.
+ * <p>
+ * <em>Warning:</em> Dependency graphs may generally contain cycles. As such a graph transformer that cannot assume for
+ * sure that cycles have already been eliminated must gracefully handle cyclic graphs, e.g. guard against infinite
+ * recursion.
+ *
+ * @see org.eclipse.aether.RepositorySystemSession#getDependencyGraphTransformer()
+ */
+public interface DependencyGraphTransformer
+{
+
+ /**
+ * Transforms the dependency graph denoted by the specified root node. The transformer may directly change the
+ * provided input graph or create a new graph, the former is recommended for performance reasons.
+ *
+ * @param node The root node of the (possibly cyclic!) graph to transform, must not be {@code null}.
+ * @param context The graph transformation context, must not be {@code null}.
+ * @return The result graph of the transformation, never {@code null}.
+ * @throws RepositoryException If the transformation failed.
+ */
+ DependencyNode transformGraph( DependencyNode node, DependencyGraphTransformationContext context )
+ throws RepositoryException;
+
+}