content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.
   */
  package org.apache.calcite.sql.ddl;
  
  import org.apache.calcite.schema.ColumnStrategy;
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlDataTypeSpec;
  import org.apache.calcite.sql.SqlIdentifier;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.SqlSpecialOperator;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.parser.SqlParserPos;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  /**
   * Parse tree for {@code UNIQUE}, {@code PRIMARY KEY} constraints.
   *
   * <p>And {@code FOREIGN KEY}, when we support it.
   */
  public class SqlColumnDeclaration extends SqlCall {
    private static final SqlSpecialOperator OPERATOR =
        new SqlSpecialOperator("COLUMN_DECL", SqlKind.COLUMN_DECL);
  
    public final SqlIdentifier name;
    public final SqlDataTypeSpec dataType;
    public final @Nullable SqlNode expression;
    public final ColumnStrategy strategy;
  
    /** Creates a SqlColumnDeclaration; use {@link SqlDdlNodes#column}. */
    SqlColumnDeclaration(SqlParserPos pos, SqlIdentifier name,
        SqlDataTypeSpec dataType, @Nullable SqlNode expression,
        ColumnStrategy strategy) {
      super(pos);
      this.name = name;
      this.dataType = dataType;
      this.expression = expression;
      this.strategy = strategy;
    }
  
    @Override public SqlOperator getOperator() {
      return OPERATOR;
    }
  
    @Override public List<SqlNode> getOperandList() {
      return ImmutableList.of(name, dataType);
    }
  
    @Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
      name.unparse(writer, 0, 0);
      dataType.unparse(writer, 0, 0);
      if (Boolean.FALSE.equals(dataType.getNullable())) {
        writer.keyword("NOT NULL");
      }
      SqlNode expression = this.expression;
      if (expression != null) {
        switch (strategy) {
        case VIRTUAL:
        case STORED:
          writer.keyword("AS");
          exp(writer, expression);
          writer.keyword(strategy.name());
          break;
        case DEFAULT:
          writer.keyword("DEFAULT");
          exp(writer, expression);
          break;
        default:
          throw new AssertionError("unexpected: " + strategy);
        }
      }
    }
  
    static void exp(SqlWriter writer, SqlNode expression) {
      if (writer.isAlwaysUseParentheses()) {
        expression.unparse(writer, 0, 0);
      } else {
        writer.sep("(");
        expression.unparse(writer, 0, 0);
        writer.sep(")");
      }
    }
  }
  