com.facebook.presto.sql.planner.SymbolToInputRewriter.java Source code

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Here is the source code for com.facebook.presto.sql.planner.SymbolToInputRewriter.java

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/*
 * Licensed 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 com.facebook.presto.sql.planner;

import com.facebook.presto.sql.tree.Expression;
import com.facebook.presto.sql.tree.ExpressionRewriter;
import com.facebook.presto.sql.tree.ExpressionTreeRewriter;
import com.facebook.presto.sql.tree.InputReference;
import com.facebook.presto.sql.tree.QualifiedNameReference;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;

import java.util.Map;

import static java.util.Objects.requireNonNull;

public class SymbolToInputRewriter extends ExpressionRewriter<Void> {
    private final Map<Symbol, Integer> symbolToChannelMapping;

    public SymbolToInputRewriter(Map<Symbol, Integer> symbolToChannelMapping) {
        requireNonNull(symbolToChannelMapping, "symbolToChannelMapping is null");
        this.symbolToChannelMapping = ImmutableMap.copyOf(symbolToChannelMapping);
    }

    @Override
    public Expression rewriteQualifiedNameReference(QualifiedNameReference node, Void context,
            ExpressionTreeRewriter<Void> treeRewriter) {
        Integer channel = symbolToChannelMapping.get(Symbol.fromQualifiedName(node.getName()));
        Preconditions.checkArgument(channel != null, "Cannot resolve symbol %s", node.getName());

        return new InputReference(channel);
    }
}