core/src/main/java/org/apache/calcite/sql/type/JavaToSqlTypeConversionRules.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.type;

import org.apache.calcite.avatica.util.ArrayImpl;

import com.google.common.collect.ImmutableMap;

import org.checkerframework.checker.nullness.qual.Nullable;
import org.locationtech.jts.geom.Geometry;

import java.math.BigDecimal;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.List;
import java.util.Map;

/**
 * JavaToSqlTypeConversionRules defines mappings from common Java types to
 * corresponding SQL types.
 */
public class JavaToSqlTypeConversionRules {
  //~ Static fields/initializers ---------------------------------------------

  private static final JavaToSqlTypeConversionRules INSTANCE =
      new JavaToSqlTypeConversionRules();

  //~ Instance fields --------------------------------------------------------

  private final Map<Class<?>, SqlTypeName> rules =
      ImmutableMap.<Class<?>, SqlTypeName>builder()
          .put(Integer.class, SqlTypeName.INTEGER)
          .put(int.class, SqlTypeName.INTEGER)
          .put(Long.class, SqlTypeName.BIGINT)
          .put(long.class, SqlTypeName.BIGINT)
          .put(Short.class, SqlTypeName.SMALLINT)
          .put(short.class, SqlTypeName.SMALLINT)
          .put(byte.class, SqlTypeName.TINYINT)
          .put(Byte.class, SqlTypeName.TINYINT)

          .put(Float.class, SqlTypeName.REAL)
          .put(float.class, SqlTypeName.REAL)
          .put(Double.class, SqlTypeName.DOUBLE)
          .put(double.class, SqlTypeName.DOUBLE)

          .put(boolean.class, SqlTypeName.BOOLEAN)
          .put(Boolean.class, SqlTypeName.BOOLEAN)
          .put(byte[].class, SqlTypeName.VARBINARY)
          .put(String.class, SqlTypeName.VARCHAR)
          .put(char[].class, SqlTypeName.VARCHAR)
          .put(Character.class, SqlTypeName.CHAR)
          .put(char.class, SqlTypeName.CHAR)

          .put(java.util.Date.class, SqlTypeName.TIMESTAMP)
          .put(Date.class, SqlTypeName.DATE)
          .put(Timestamp.class, SqlTypeName.TIMESTAMP)
          .put(Time.class, SqlTypeName.TIME)
          .put(BigDecimal.class, SqlTypeName.DECIMAL)

          .put(Geometry.class, SqlTypeName.GEOMETRY)

          .put(ResultSet.class, SqlTypeName.CURSOR)
          .put(ColumnList.class, SqlTypeName.COLUMN_LIST)
          .put(ArrayImpl.class, SqlTypeName.ARRAY)
          .put(List.class, SqlTypeName.ARRAY)
          .put(Map.class, SqlTypeName.MAP)
          .put(Void.class, SqlTypeName.NULL)
          .build();

  //~ Methods ----------------------------------------------------------------

  /**
   * Returns the
   * {@link org.apache.calcite.util.Glossary#SINGLETON_PATTERN singleton}
   * instance.
   */
  public static JavaToSqlTypeConversionRules instance() {
    return INSTANCE;
  }

  /**
   * Returns a corresponding {@link SqlTypeName} for a given Java class.
   *
   * @param javaClass the Java class to lookup
   * @return a corresponding SqlTypeName if found, otherwise null is returned
   */
  public @Nullable SqlTypeName lookup(Class javaClass) {
    return rules.get(javaClass);
  }

  /**
   * Make this public when needed. To represent COLUMN_LIST SQL value, we need
   * a type distinguishable from {@link List} in user-defined types.
   */
  private interface ColumnList extends List {
  }
}