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1   package org.eclipse.aether.internal.impl.collect;
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 java.util.HashMap;
23  import java.util.Map;
24  
25  import org.eclipse.aether.RepositorySystemSession;
26  import org.eclipse.aether.artifact.ArtifactType;
27  import org.eclipse.aether.artifact.ArtifactTypeRegistry;
28  
29  /**
30   * A short-lived artifact type registry that caches results from a presumably slower type registry.
31   * Internal helper class for collector implementations.
32   */
33  public class CachingArtifactTypeRegistry
34      implements ArtifactTypeRegistry
35  {
36  
37      private final ArtifactTypeRegistry delegate;
38  
39      private final Map<String, ArtifactType> types;
40  
41      public static ArtifactTypeRegistry newInstance( RepositorySystemSession session )
42      {
43          return newInstance( session.getArtifactTypeRegistry() );
44      }
45  
46      public static ArtifactTypeRegistry newInstance( ArtifactTypeRegistry delegate )
47      {
48          return ( delegate != null ) ? new CachingArtifactTypeRegistry( delegate ) : null;
49      }
50  
51      private CachingArtifactTypeRegistry( ArtifactTypeRegistry delegate )
52      {
53          this.delegate = delegate;
54          types = new HashMap<>();
55      }
56  
57      public ArtifactType get( String typeId )
58      {
59          ArtifactType type = types.get( typeId );
60  
61          if ( type == null )
62          {
63              type = delegate.get( typeId );
64              types.put( typeId, type );
65          }
66  
67          return type;
68      }
69  
70  }