ReactorModelCache.java

package org.apache.maven.project;

/*
 * 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 java.util.HashMap;
import java.util.Map;

import org.apache.maven.model.building.ModelCache;

/**
 * A simple model cache used to accelerate model building during a reactor build.
 *
 * @author Benjamin Bentmann
 */
class ReactorModelCache
    implements ModelCache
{

    private final Map<CacheKey, Object> models = new HashMap<>( 256 );

    public Object get( String groupId, String artifactId, String version, String tag )
    {
        return models.get( new CacheKey( groupId, artifactId, version, tag ) );
    }

    public void put( String groupId, String artifactId, String version, String tag, Object data )
    {
        models.put( new CacheKey( groupId, artifactId, version, tag ), data );
    }

    private static final class CacheKey
    {

        private final String groupId;

        private final String artifactId;

        private final String version;

        private final String tag;

        private final int hashCode;

        CacheKey( String groupId, String artifactId, String version, String tag )
        {
            this.groupId = ( groupId != null ) ? groupId : "";
            this.artifactId = ( artifactId != null ) ? artifactId : "";
            this.version = ( version != null ) ? version : "";
            this.tag = ( tag != null ) ? tag : "";

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

        @Override
        public boolean equals( Object obj )
        {
            if ( this == obj )
            {
                return true;
            }

            if ( !( obj instanceof CacheKey ) )
            {
                return false;
            }

            CacheKey that = (CacheKey) obj;

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

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

    }

}