/*
 * 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.
 */
package org.eclipse.aether.internal.impl.collect;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.artifact.ArtifactType;
import org.eclipse.aether.artifact.ArtifactTypeRegistry;

/**
 * A short-lived artifact type registry that caches results from a presumably slower type registry.
 * Internal helper class for collector implementations.
 */
public class CachingArtifactTypeRegistry implements ArtifactTypeRegistry {

    private final ArtifactTypeRegistry delegate;

    private final Map<String, ArtifactType> types;

    public static ArtifactTypeRegistry newInstance(RepositorySystemSession session) {
        return newInstance(session.getArtifactTypeRegistry());
    }

    public static ArtifactTypeRegistry newInstance(ArtifactTypeRegistry delegate) {
        return (delegate != null) ? new CachingArtifactTypeRegistry(delegate) : null;
    }

    private CachingArtifactTypeRegistry(ArtifactTypeRegistry delegate) {
        this.delegate = delegate;
        types = new HashMap<>();
    }

    public ArtifactType get(String typeId) {
        ArtifactType type = types.get(typeId);

        if (type == null) {
            type = delegate.get(typeId);
            types.put(typeId, type);
        }

        return type;
    }
}
