org.argeo.slc.repo/src/org/eclipse/aether/collection/DependencyTraverser.java

   1 /*******************************************************************************
   2  * Copyright (c) 2010, 2014 Sonatype, Inc.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *    Sonatype, Inc. - initial API and implementation
  10  *******************************************************************************/
  11 package org.eclipse.aether.collection;
  12
  13 import org.eclipse.aether.graph.Dependency;
  14
  15 /**
  16  * Decides whether the dependencies of a dependency node should be traversed as well.
  17  * <p>
  18  * <strong>Note:</strong> Implementations must be stateless.
  19  * <p>
  20  * <em>Warning:</em> This hook is called from a hot spot and therefore implementations should pay attention to
  21  * performance. Among others, implementations should provide a semantic {@link Object#equals(Object) equals()} method.
  22  *
  23  * @see org.eclipse.aether.RepositorySystemSession#getDependencyTraverser()
  24  * @see org.eclipse.aether.RepositorySystem#collectDependencies(org.eclipse.aether.RepositorySystemSession,
  25  *      CollectRequest)
  26  */
  27 public interface DependencyTraverser
  28 {
  29
  30     /**
  31      * Decides whether the dependencies of the specified dependency should be traversed.
  32      *
  33      * @param dependency The dependency to check, must not be {@code null}.
  34      * @return {@code true} if the dependency graph builder should recurse into the specified dependency and process its
  35      *         dependencies, {@code false} otherwise.
  36      */
  37     boolean traverseDependency( Dependency dependency );
  38
  39     /**
  40      * Derives a dependency traverser that will be used to decide whether the transitive dependencies of the dependency
  41      * given in the collection context shall be traversed. When calculating the child traverser, implementors are
  42      * strongly advised to simply return the current instance if nothing changed to help save memory.
  43      *
  44      * @param context The dependency collection context, must not be {@code null}.
  45      * @return The dependency traverser for the target node or {@code null} if dependencies should be unconditionally
  46      *         traversed in the sub graph.
  47      */
  48     DependencyTraverser deriveChildTraverser( DependencyCollectionContext context );
  49
  50 }