001package org.eclipse.aether.internal.impl.collect;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 * 
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 * 
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import java.util.HashMap;
023import java.util.Map;
024
025import org.eclipse.aether.RepositorySystemSession;
026import org.eclipse.aether.artifact.ArtifactType;
027import org.eclipse.aether.artifact.ArtifactTypeRegistry;
028
029/**
030 * A short-lived artifact type registry that caches results from a presumably slower type registry.
031 * Internal helper class for collector implementations.
032 */
033public class CachingArtifactTypeRegistry
034    implements ArtifactTypeRegistry
035{
036
037    private final ArtifactTypeRegistry delegate;
038
039    private final Map<String, ArtifactType> types;
040
041    public static ArtifactTypeRegistry newInstance( RepositorySystemSession session )
042    {
043        return newInstance( session.getArtifactTypeRegistry() );
044    }
045
046    public static ArtifactTypeRegistry newInstance( ArtifactTypeRegistry delegate )
047    {
048        return ( delegate != null ) ? new CachingArtifactTypeRegistry( delegate ) : null;
049    }
050
051    private CachingArtifactTypeRegistry( ArtifactTypeRegistry delegate )
052    {
053        this.delegate = delegate;
054        types = new HashMap<>();
055    }
056
057    public ArtifactType get( String typeId )
058    {
059        ArtifactType type = types.get( typeId );
060
061        if ( type == null )
062        {
063            type = delegate.get( typeId );
064            types.put( typeId, type );
065        }
066
067        return type;
068    }
069
070}