001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.eclipse.aether.transport.wagon;
020
021import org.apache.maven.wagon.Wagon;
022
023/**
024 * A component to acquire and release wagon instances for uploads/downloads.
025 */
026public interface WagonProvider {
027
028    /**
029     * Acquires a wagon instance that matches the specified role hint. The role hint is derived from the URI scheme,
030     * e.g. "http" or "file".
031     *
032     * @param roleHint The role hint to get a wagon for, must not be {@code null}.
033     * @return The requested wagon instance, never {@code null}.
034     * @throws Exception If no wagon could be retrieved for the specified role hint.
035     */
036    Wagon lookup(String roleHint) throws Exception;
037
038    /**
039     * Releases the specified wagon. A wagon provider may either free any resources allocated for the wagon instance or
040     * return the instance back to a pool for future use.
041     *
042     * @param wagon The wagon to release, may be {@code null}.
043     */
044    void release(Wagon wagon);
045}