core/src/main/java/org/apache/calcite/sql/ddl/SqlColumnDeclaration.java

/*
 * 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(")");
    }
  }
}