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.util.artifact; 020 021import org.eclipse.aether.artifact.ArtifactType; 022import org.eclipse.aether.artifact.ArtifactTypeRegistry; 023 024/** 025 * An artifact type registry which first consults its own mappings and in case of an unknown type falls back to another 026 * type registry. 027 */ 028public class OverlayArtifactTypeRegistry extends SimpleArtifactTypeRegistry { 029 030 private final ArtifactTypeRegistry delegate; 031 032 /** 033 * Creates a new artifact type registry with initially no registered artifact types and the specified fallback 034 * registry. Use {@link #add(ArtifactType)} to populate the registry. 035 * 036 * @param delegate The artifact type registry to fall back to, may be {@code null}. 037 */ 038 public OverlayArtifactTypeRegistry(ArtifactTypeRegistry delegate) { 039 this.delegate = delegate; 040 } 041 042 /** 043 * Adds the specified artifact type to the registry. 044 * 045 * @param type The artifact type to add, must not be {@code null}. 046 * @return This registry for chaining, never {@code null}. 047 */ 048 @Override 049 public OverlayArtifactTypeRegistry add(ArtifactType type) { 050 super.add(type); 051 return this; 052 } 053 054 @Override 055 public ArtifactType get(String typeId) { 056 ArtifactType type = super.get(typeId); 057 058 if (type == null && delegate != null) { 059 type = delegate.get(typeId); 060 } 061 062 return type; 063 } 064}