fe/src/main/java/org/apache/impala/common/ColumnAliasGenerator.java

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// 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
//
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package org.apache.impala.common;

import java.util.List;

import com.google.common.base.Preconditions;

public class ColumnAliasGenerator extends AliasGenerator {
  private static final String DEFAULT_COL_ALIAS_PREFIX = "$c$";

  public ColumnAliasGenerator(List<String> existingLabels, String prefix) {
    Preconditions.checkNotNull(existingLabels);
    aliasPrefix_ = prefix != null ? prefix : DEFAULT_COL_ALIAS_PREFIX;
    usedAliases_.addAll(existingLabels);
  }
}