001package org.eclipse.aether.collection;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 * 
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 * 
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.eclipse.aether.RepositorySystemSession;
023
024/**
025 * A context used during dependency collection to exchange information within a chain of dependency graph transformers.
026 * 
027 * @see DependencyGraphTransformer
028 * @noimplement This interface is not intended to be implemented by clients.
029 * @noextend This interface is not intended to be extended by clients.
030 */
031public interface DependencyGraphTransformationContext
032{
033
034    /**
035     * Gets the repository system session during which the graph transformation happens.
036     * 
037     * @return The repository system session, never {@code null}.
038     */
039    RepositorySystemSession getSession();
040
041    /**
042     * Gets a keyed value from the context.
043     * 
044     * @param key The key used to query the value, must not be {@code null}.
045     * @return The queried value or {@code null} if none.
046     */
047    Object get( Object key );
048
049    /**
050     * Puts a keyed value into the context.
051     * 
052     * @param key The key used to store the value, must not be {@code null}.
053     * @param value The value to store, may be {@code null} to remove the mapping.
054     * @return The previous value associated with the key or {@code null} if none.
055     */
056    Object put( Object key, Object value );
057
058}