Unit.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.runtime;

/**
 * Synthetic record with zero fields.
 *
 * <p>Since all instances are identical, {@code Unit} is a singleton.
 */
public class Unit implements Comparable<Unit> {
  public static final Unit INSTANCE = new Unit();

  private Unit() {
  }

  @Override public int compareTo(Unit that) {
    return 0;
  }

  @Override public String toString() {
    return "{}";
  }
}