/*
 * 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.collection.DependencyGraphTransformationContext;

import static java.util.Objects.requireNonNull;

/**
 * Default implementation of {@link DependencyGraphTransformationContext}.
 * Internal helper class for collector implementations.
 */
public class DefaultDependencyGraphTransformationContext implements DependencyGraphTransformationContext {

    private final RepositorySystemSession session;

    private final Map<Object, Object> map;

    public DefaultDependencyGraphTransformationContext(RepositorySystemSession session) {
        this.session = session;
        this.map = new HashMap<>();
    }

    @Override
    public RepositorySystemSession getSession() {
        return session;
    }

    @Override
    public Object get(Object key) {
        return map.get(requireNonNull(key, "key cannot be null"));
    }

    @Override
    public Object put(Object key, Object value) {
        requireNonNull(key, "key cannot be null");
        if (value != null) {
            return map.put(key, value);
        } else {
            return map.remove(key);
        }
    }

    @Override
    public String toString() {
        return String.valueOf(map);
    }
}
