/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.analyze.symbol;

import io.crate.metadata.ReplaceMode;
import io.crate.metadata.ReplacingSymbolVisitor;

import java.util.Map;

/**
 * A symbol visitor which replaces all symbols mapped in the map given as context.
 */
public class MappingSymbolVisitor extends ReplacingSymbolVisitor<Map<? extends Symbol, ? extends Symbol>> {

    private static final MappingSymbolVisitor REPLACING = new MappingSymbolVisitor(ReplaceMode.MUTATE);
    private static final MappingSymbolVisitor COPYING = new MappingSymbolVisitor(ReplaceMode.COPY);

    public static MappingSymbolVisitor inPlace() {
        return REPLACING;
    }

    public static MappingSymbolVisitor copying() {
        return COPYING;
    }

    protected MappingSymbolVisitor(ReplaceMode mode) {
        super(mode);
    }

    @Override
    public Symbol process(Symbol symbol, Map<? extends Symbol, ? extends Symbol> context) {
        Symbol mapped = context.get(symbol);
        if (mapped != null) {
            return mapped;
        }
        return super.process(symbol, context);
    }
}