PeriodValue.java

// Copyright (C) 2006 Google Inc.
//
// 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 com.google.ical.values;


/**
 * a half-open range of {@link DateValue}s.  The start is inclusive, and the
 * end is exclusive.  The end must be on or after the start.  When the start and
 * end are the same, the period is zero width, i.e. contains zero seconds.
 *
 * @author mikesamuel+svn@gmail.com (Mike Samuel)
 */
public interface PeriodValue {

  /**
   * the start of the period.
   * @return non null.
   */
  DateValue start();

  /**
   * the end of the period.
   * The end must be >= {@link #start()}, and
   * <tt>(start() instanceof {@link TimeValue}) ==
   *     (end() instanceof TimeValue)</tt>.
   * @return non null.
   */
  DateValue end();

  /**
   * true iff this period overlaps the given period.
   * @param pv not null.
   */
  boolean intersects(PeriodValue pv);

  /**
   * true iff this period completely contains the given period.
   * @param pv not null.
   */
  boolean contains(PeriodValue pv);

}  // PeriodValue