001package org.eclipse.aether.resolution;
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;
023import org.eclipse.aether.artifact.Artifact;
024import org.eclipse.aether.metadata.Metadata;
025
026/**
027 * Controls the caching of resolution errors for artifacts/metadata from remote repositories. If caching is enabled for
028 * a given resource, a marker will be set (usually somewhere in the local repository) to suppress repeated resolution
029 * attempts for the broken resource, thereby avoiding expensive but useless network IO. The error marker is considered
030 * stale once the repository's update policy has expired at which point a future resolution attempt will be allowed.
031 * Error caching considers the current network settings such that fixes to the configuration like authentication or
032 * proxy automatically trigger revalidation with the remote side regardless of the time elapsed since the previous
033 * resolution error.
034 * 
035 * @see RepositorySystemSession#getResolutionErrorPolicy()
036 */
037public interface ResolutionErrorPolicy
038{
039
040    /**
041     * Bit mask indicating that resolution errors should not be cached in the local repository. This forces the system
042     * to always query the remote repository for locally missing artifacts/metadata.
043     */
044    int CACHE_DISABLED = 0x00;
045
046    /**
047     * Bit flag indicating whether missing artifacts/metadata should be cached in the local repository. If caching is
048     * enabled, resolution will not be reattempted until the update policy for the affected resource has expired.
049     */
050    int CACHE_NOT_FOUND = 0x01;
051
052    /**
053     * Bit flag indicating whether connectivity/transfer errors (e.g. unreachable host, bad authentication) should be
054     * cached in the local repository. If caching is enabled, resolution will not be reattempted until the update policy
055     * for the affected resource has expired.
056     */
057    int CACHE_TRANSFER_ERROR = 0x02;
058
059    /**
060     * Bit mask indicating that all resolution errors should be cached in the local repository.
061     */
062    int CACHE_ALL = CACHE_NOT_FOUND | CACHE_TRANSFER_ERROR;
063
064    /**
065     * Gets the error policy for an artifact.
066     * 
067     * @param session The repository session during which the policy is determined, must not be {@code null}.
068     * @param request The policy request holding further details, must not be {@code null}.
069     * @return The bit mask describing the desired error policy.
070     */
071    int getArtifactPolicy( RepositorySystemSession session, ResolutionErrorPolicyRequest<Artifact> request );
072
073    /**
074     * Gets the error policy for some metadata.
075     * 
076     * @param session The repository session during which the policy is determined, must not be {@code null}.
077     * @param request The policy request holding further details, must not be {@code null}.
078     * @return The bit mask describing the desired error policy.
079     */
080    int getMetadataPolicy( RepositorySystemSession session, ResolutionErrorPolicyRequest<Metadata> request );
081
082}