maven-resolver-provider/src/main/java/org/apache/maven/repository/internal/DefaultModelCache.java

package org.apache.maven.repository.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.apache.maven.model.building.ModelCache;
import org.eclipse.aether.RepositoryCache;
import org.eclipse.aether.RepositorySystemSession;

/**
 * A model builder cache backed by the repository system cache.
 *
 * @author Benjamin Bentmann
 */
class DefaultModelCache
    implements ModelCache
{

    private final RepositorySystemSession session;

    private final RepositoryCache cache;

    public static ModelCache newInstance( RepositorySystemSession session )
    {
        if ( session.getCache() == null )
        {
            return null;
        }
        else
        {
            return new DefaultModelCache( session );
        }
    }

    private DefaultModelCache( RepositorySystemSession session )
    {
        this.session = session;
        this.cache = session.getCache();
    }

    public Object get( String groupId, String artifactId, String version, String tag )
    {
        return cache.get( session, new Key( groupId, artifactId, version, tag ) );
    }

    public void put( String groupId, String artifactId, String version, String tag, Object data )
    {
        cache.put( session, new Key( groupId, artifactId, version, tag ), data );
    }

    static class Key
    {

        private final String groupId;

        private final String artifactId;

        private final String version;

        private final String tag;

        private final int hash;

        Key( String groupId, String artifactId, String version, String tag )
        {
            this.groupId = groupId;
            this.artifactId = artifactId;
            this.version = version;
            this.tag = tag;

            int h = 17;
            h = h * 31 + this.groupId.hashCode();
            h = h * 31 + this.artifactId.hashCode();
            h = h * 31 + this.version.hashCode();
            h = h * 31 + this.tag.hashCode();
            hash = h;
        }

        @Override
        public boolean equals( Object obj )
        {
            if ( this == obj )
            {
                return true;
            }
            if ( null == obj || !getClass().equals( obj.getClass() ) )
            {
                return false;
            }

            Key that = (Key) obj;
            return artifactId.equals( that.artifactId ) && groupId.equals( that.groupId )
                && version.equals( that.version ) && tag.equals( that.tag );
        }

        @Override
        public int hashCode()
        {
            return hash;
        }

    }
}