/*******************************************************************************
 * Copyright (c) 2010, 2013 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 java.util.List;

import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.graph.Dependency;

/**
 * A context used during dependency collection to update the dependency manager, selector and traverser.
 * 
 * @see DependencyManager#deriveChildManager(DependencyCollectionContext)
 * @see DependencyTraverser#deriveChildTraverser(DependencyCollectionContext)
 * @see DependencySelector#deriveChildSelector(DependencyCollectionContext)
 * @see VersionFilter#deriveChildFilter(DependencyCollectionContext)
 * @noimplement This interface is not intended to be implemented by clients.
 * @noextend This interface is not intended to be extended by clients.
 */
public interface DependencyCollectionContext
{

    /**
     * Gets the repository system session during which the dependency collection happens.
     * 
     * @return The repository system session, never {@code null}.
     */
    RepositorySystemSession getSession();

    /**
     * Gets the artifact whose children are to be processed next during dependency collection. For all nodes but the
     * root, this is simply shorthand for {@code getDependency().getArtifact()}. In case of the root node however,
     * {@link #getDependency()} might be {@code null} while the node still has an artifact which serves as its label and
     * is not to be resolved.
     * 
     * @return The artifact whose children are going to be processed or {@code null} in case of the root node without
     *         dependency and label.
     */
    Artifact getArtifact();

    /**
     * Gets the dependency whose children are to be processed next during dependency collection.
     * 
     * @return The dependency whose children are going to be processed or {@code null} in case of the root node without
     *         dependency.
     */
    Dependency getDependency();

    /**
     * Gets the dependency management information that was contributed by the artifact descriptor of the current
     * dependency.
     * 
     * @return The dependency management information, never {@code null}.
     */
    List<Dependency> getManagedDependencies();

}