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1   package org.eclipse.aether.util.graph.selector;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   * 
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   * 
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import org.eclipse.aether.collection.DependencyCollectionContext;
23  import org.eclipse.aether.collection.DependencySelector;
24  import org.eclipse.aether.graph.Dependency;
25  
26  /**
27   * A dependency selector that excludes optional dependencies which occur beyond level one of the dependency graph.
28   * 
29   * @see Dependency#isOptional()
30   */
31  public final class OptionalDependencySelector
32      implements DependencySelector
33  {
34  
35      private final int depth;
36  
37      /**
38       * Creates a new selector to exclude optional transitive dependencies.
39       */
40      public OptionalDependencySelector()
41      {
42          depth = 0;
43      }
44  
45      private OptionalDependencySelector( int depth )
46      {
47          this.depth = depth;
48      }
49  
50      public boolean selectDependency( Dependency dependency )
51      {
52          return depth < 2 || !dependency.isOptional();
53      }
54  
55      public DependencySelector deriveChildSelector( DependencyCollectionContext context )
56      {
57          if ( depth >= 2 )
58          {
59              return this;
60          }
61  
62          return new OptionalDependencySelector( depth + 1 );
63      }
64  
65      @Override
66      public boolean equals( Object obj )
67      {
68          if ( this == obj )
69          {
70              return true;
71          }
72          else if ( null == obj || !getClass().equals( obj.getClass() ) )
73          {
74              return false;
75          }
76  
77          OptionalDependencySelector that = (OptionalDependencySelector) obj;
78          return depth == that.depth;
79      }
80  
81      @Override
82      public int hashCode()
83      {
84          int hash = getClass().hashCode();
85          hash = hash * 31 + depth;
86          return hash;
87      }
88  
89      @Override
90      public String toString()
91      {
92          return String.format( "%s(depth: %d)", this.getClass().getSimpleName(), this.depth );
93      }
94  
95  }