/*
 * Copyright 2012 <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
 * 
 * Licensed 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.ocpsoft.prettytime;


/**
 * Defines a Unit of time (e.g. seconds, minutes, hours) and its conversion to milliseconds.
 * 
 * @author <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
 */
public interface TimeUnit {

   /**
    * The number of milliseconds represented by each instance of this TimeUnit.
    * Must be a positive number greater than zero.
    */
   public long getMillisPerUnit();

   /**
    * The maximum quantity of this Unit to be used as a threshold for the next
    * largest Unit (e.g. if one <code>Second</code> represents 1000ms, and
    * <code>Second</code> has a maxQuantity of 5, then if the difference
    * between compared timestamps is larger than 5000ms, PrettyTime will move
    * on to the next smallest TimeUnit for calculation; <code>Minute</code>, by
    * default)
    * <p>
    * millisPerUnit * maxQuantity = maxAllowedMs
    * <p>
    * If maxQuantity is zero, it will be equal to the next highest
    * <code>TimeUnit.getMillisPerUnit() /
    * this.getMillisPerUnit()</code> or infinity if there are no greater
    * TimeUnits
    */
   public long getMaxQuantity();
}