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.collection;
20
21 import org.eclipse.aether.graph.Dependency;
22
23 /**
24 * Decides what dependencies to include in the dependency graph.
25 * <p>
26 * <strong>Note:</strong> Implementations must be stateless.
27 * <p>
28 * <em>Warning:</em> This hook is called from a hot spot and therefore implementations should pay attention to
29 * performance. Among others, implementations should provide a semantic {@link Object#equals(Object) equals()} method.
30 *
31 * @see org.eclipse.aether.RepositorySystemSession#getDependencySelector()
32 * @see org.eclipse.aether.RepositorySystem#collectDependencies(org.eclipse.aether.RepositorySystemSession,
33 * CollectRequest)
34 */
35 public interface DependencySelector {
36
37 /**
38 * Decides whether the specified dependency should be included in the dependency graph.
39 *
40 * @param dependency The dependency to check, must not be {@code null}.
41 * @return {@code false} if the dependency should be excluded from the children of the current node, {@code true}
42 * otherwise.
43 */
44 boolean selectDependency(Dependency dependency);
45
46 /**
47 * Derives a dependency selector for the specified collection context. When calculating the child selector,
48 * implementors are strongly advised to simply return the current instance if nothing changed to help save memory.
49 *
50 * @param context The dependency collection context, must not be {@code null}.
51 * @return The dependency selector for the target node or {@code null} if dependencies should be unconditionally
52 * included in the sub graph.
53 */
54 DependencySelector deriveChildSelector(DependencyCollectionContext context);
55 }