ColumnDef.java

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// Copyright 2012 Cloudera Inc.
//
// 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.cloudera.impala.analysis;

import org.apache.hadoop.hive.metastore.MetaStoreUtils;

import com.cloudera.impala.catalog.Type;
import com.cloudera.impala.common.AnalysisException;
import com.cloudera.impala.thrift.TColumn;
import com.google.common.base.Preconditions;

public class ColumnDef {
  private final String colName_;
  private final String comment_;

  // Required in CREATE/ALTER TABLE stmts. Set to NULL in CREATE/ALTER VIEW stmts,
  // for which we setType() after analyzing the defining view definition stmt.
  private final TypeDef typeDef_;
  private Type type_;

  public ColumnDef(String colName, TypeDef typeDef, String comment) {
    colName_ = colName;
    typeDef_ = typeDef;
    comment_ = comment;
  }

  public void setType(Type type) { type_ = type; }
  public Type getType() { return type_; }
  public TypeDef getTypeDef() { return typeDef_; }
  public String getColName() { return colName_; }
  public String getComment() { return comment_; }

  public void analyze() throws AnalysisException {
    // Check whether the column name meets the Metastore's requirements.
    if (!MetaStoreUtils.validateName(colName_)) {
      throw new AnalysisException("Invalid column/field name: " + colName_);
    }
    if (typeDef_ != null) {
      typeDef_.analyze(null);
      type_ = typeDef_.getType();
    }
    Preconditions.checkNotNull(type_);
    Preconditions.checkState(type_.isValid());
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder(colName_);
    if (type_ != null) {
      sb.append(" " + type_.toString());
    } else {
      sb.append(" " + typeDef_.toString());
    }
    if (comment_ != null) sb.append(String.format(" COMMENT '%s'", comment_));
    return sb.toString();
  }

  public TColumn toThrift() {
    TColumn col = new TColumn(new TColumn(getColName(), type_.toThrift()));
    col.setComment(getComment());
    return col;
  }
}