1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.eclipse.aether.internal.impl.scope;
20
21 import org.eclipse.aether.impl.scope.InternalScopeManager;
22 import org.eclipse.aether.scope.DependencyScope;
23 import org.eclipse.aether.scope.ScopeManager;
24 import org.eclipse.aether.util.graph.transformer.ConflictResolver;
25 import org.eclipse.aether.util.graph.transformer.ConflictResolver.ScopeContext;
26 import org.eclipse.aether.util.graph.transformer.ConflictResolver.ScopeDeriver;
27
28 import static java.util.Objects.requireNonNull;
29
30 /**
31 * A scope deriver for use with {@link ConflictResolver} that supports the scopes from {@link ScopeManager}. It basically
32 * chooses "narrowest" scope, based on parent and child scopes.
33 * <p>
34 * This class also "bridges" between {@link DependencyScope} and Resolver that uses plain string labels for scopes.
35 *
36 * @since 4.0.0
37 */
38 public final class ManagedScopeDeriver extends ScopeDeriver {
39 private final InternalScopeManager scopeManager;
40 private final DependencyScope systemScope;
41
42 public ManagedScopeDeriver(InternalScopeManager scopeManager) {
43 this.scopeManager = requireNonNull(scopeManager, "scopeManager");
44 this.systemScope = scopeManager.getSystemDependencyScope().orElse(null);
45 }
46
47 @Override
48 public void deriveScope(ScopeContext context) {
49 context.setDerivedScope(getDerivedScope(context.getParentScope(), context.getChildScope()));
50 }
51
52 /**
53 * Visible for testing. It chooses "narrowest" scope out of parent or child, unless child is system scope.
54 */
55 public String getDerivedScope(String parentScope, String childScope) {
56 // ask parent scope (nullable)
57 DependencyScope parent = parentScope != null
58 ? scopeManager.getDependencyScope(parentScope).orElse(null)
59 : null;
60 // ask child scope (non-nullable, but may be unknown scope to manager)
61 DependencyScope child = scopeManager.getDependencyScope(childScope).orElse(null);
62
63 // if system scope exists and child is system scope: system
64 if (systemScope != null && systemScope == child) {
65 return systemScope.getId();
66 }
67 // if no parent (i.e. is root): child scope as-is
68 if (parent == null) {
69 return child != null ? child.getId() : "";
70 }
71 if (child == null) {
72 return parent.getId();
73 }
74 // otherwise the narrowest out of parent or child
75 int parentWidth = scopeManager.getDependencyScopeWidth(parent);
76 int childWidth = scopeManager.getDependencyScopeWidth(child);
77 if (parentWidth < childWidth) {
78 return parent.getId();
79 } else {
80 return child.getId();
81 }
82 }
83 }