/*
 * 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.apache.tinkerpop.gremlin.tinkergraph.structure;

import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.structure.util.GraphVariableHelper;
import org.apache.tinkerpop.gremlin.structure.util.StringFactory;

import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 */
public final class TinkerGraphVariables implements Graph.Variables {

    private final Map<String, Object> variables = new ConcurrentHashMap<>();

    public TinkerGraphVariables() {

    }

    @Override
    public Set<String> keys() {
        return this.variables.keySet();
    }

    @Override
    public <R> Optional<R> get(final String key) {
        return Optional.ofNullable((R) this.variables.get(key));
    }

    @Override
    public void remove(final String key) {
        this.variables.remove(key);
    }

    @Override
    public void set(final String key, final Object value) {
        GraphVariableHelper.validateVariable(key, value);
        this.variables.put(key, value);
    }

    public String toString() {
        return StringFactory.graphVariablesString(this);
    }
}