/**
* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you under the Educational
* Community 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://opensource.org/licenses/ecl2.txt
*
* 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.opencastproject.metadata.dublincore;
import java.util.Date;
/**
* A time related algebraic data type.
*/
public abstract class Temporal {
// prohibit inheritance from outside this class
private Temporal() {
}
/**
* An instant in time.
*/
public static Temporal instant(final Date instant) {
if (instant == null)
throw new IllegalArgumentException("instant must not be null");
return new Temporal() {
public Date getInstant() {
return instant;
}
@Override
public <A> A fold(Match<A> v) {
return v.instant(instant);
}
};
}
/**
* A period in time limited by at least one instant.
*/
public static Temporal period(final DCMIPeriod period) {
if (period == null)
throw new IllegalArgumentException("period must not be null");
return new Temporal() {
public DCMIPeriod getPeriod() {
return period;
}
@Override
public <A> A fold(Match<A> v) {
return v.period(period);
}
};
}
/**
* A time span measured in milliseconds.
*/
public static Temporal duration(final long duration) {
if (duration < 0)
throw new IllegalArgumentException("duration must be positive or zero");
return new Temporal() {
public long getDuration() {
return duration;
}
@Override
public <A> A fold(Match<A> v) {
return v.duration(duration);
}
};
}
/**
* Safe decomposition.
*/
public abstract <A> A fold(Match<A> v);
/**
* Safe temporal decomposition.
*/
public interface Match<A> {
A period(DCMIPeriod period);
A instant(Date instant);
A duration(long duration);
}
}