/*
* 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.InputReference;
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.QualifiedNameReference;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import static com.google.common.base.Preconditions.checkNotNull;
public class SymbolToInputRewriter
extends ExpressionRewriter<Void>
{
private final Map<Symbol, Integer> symbolToChannelMapping;
public SymbolToInputRewriter(Map<Symbol, Integer> symbolToChannelMapping)
{
checkNotNull(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);
}
}