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.rel.type;
  
  import java.util.Map;
  
  /**
   * RelDataTypeField represents the definition of a field in a structured
   * {@link RelDataType}.
   *
   * <p>Extends the {@link java.util.Map.Entry} interface to allow convenient
   * inter-operation with Java collections classes. In any implementation of this
   * interface, {@link #getKey()} must be equivalent to {@link #getName()}
   * and {@link #getValue()} must be equivalent to {@link #getType()}.
   */
  public interface RelDataTypeField extends Map.Entry<String, RelDataType> {
  
    /**
     * Function to transform a set of {@link RelDataTypeField} to
     * a set of {@link Integer} of the field keys.
     *
     * @deprecated Use {@code RelDataTypeField::getIndex}
     */
    @Deprecated // to be removed before 2.0
    @SuppressWarnings("nullability")
    class ToFieldIndex
        implements com.google.common.base.Function<RelDataTypeField, Integer> {
      @Override public Integer apply(RelDataTypeField o) {
        return o.getIndex();
      }
    }
  
    /**
     * Function to transform a set of {@link RelDataTypeField} to
     * a set of {@link String} of the field names.
     *
     * @deprecated Use {@code RelDataTypeField::getName}
     */
    @Deprecated // to be removed before 2.0
    @SuppressWarnings("nullability")
    class ToFieldName
        implements com.google.common.base.Function<RelDataTypeField, String> {
      @Override public String apply(RelDataTypeField o) {
        return o.getName();
      }
    }
  
    //~ Methods ----------------------------------------------------------------
  
    /**
     * Gets the name of this field, which is unique within its containing type.
     *
     * @return field name
     */
    String getName();
  
    /**
     * Gets the ordinal of this field within its containing type.
     *
     * @return 0-based ordinal
     */
    int getIndex();
  
    /**
     * Gets the type of this field.
     *
     * @return field type
     */
    RelDataType getType();
  
    /**
     * Returns true if this is a dynamic star field.
     */
    boolean isDynamicStar();
  }
  