Merge tag 'v2.3.20' into testing

[gpl/argeo-jcr.git] / org.argeo.slc.repo / src / org / eclipse / aether / collection / DependencyTraverser.java

diff --git a/org.argeo.slc.repo/src/org/eclipse/aether/collection/DependencyTraverser.java b/org.argeo.slc.repo/src/org/eclipse/aether/collection/DependencyTraverser.java
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+/*******************************************************************************
+ * 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.graph.Dependency;
+
+/**
+ * Decides whether the dependencies of a dependency node should be traversed as well.
+ * <p>
+ * <strong>Note:</strong> Implementations must be stateless.
+ * <p>
+ * <em>Warning:</em> This hook is called from a hot spot and therefore implementations should pay attention to
+ * performance. Among others, implementations should provide a semantic {@link Object#equals(Object) equals()} method.
+ * 
+ * @see org.eclipse.aether.RepositorySystemSession#getDependencyTraverser()
+ * @see org.eclipse.aether.RepositorySystem#collectDependencies(org.eclipse.aether.RepositorySystemSession,
+ *      CollectRequest)
+ */
+public interface DependencyTraverser
+{
+
+    /**
+     * Decides whether the dependencies of the specified dependency should be traversed.
+     * 
+     * @param dependency The dependency to check, must not be {@code null}.
+     * @return {@code true} if the dependency graph builder should recurse into the specified dependency and process its
+     *         dependencies, {@code false} otherwise.
+     */
+    boolean traverseDependency( Dependency dependency );
+
+    /**
+     * Derives a dependency traverser that will be used to decide whether the transitive dependencies of the dependency
+     * given in the collection context shall be traversed. When calculating the child traverser, implementors are
+     * strongly advised to simply return the current instance if nothing changed to help save memory.
+     * 
+     * @param context The dependency collection context, must not be {@code null}.
+     * @return The dependency traverser for the target node or {@code null} if dependencies should be unconditionally
+     *         traversed in the sub graph.
+     */
+    DependencyTraverser deriveChildTraverser( DependencyCollectionContext context );
+
+}