org.github.evenjn.yarn.Bi Maven / Gradle / Ivy

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/**
 *
 * Copyright 2017 Marco Trevisan
 *
 * 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.github.evenjn.yarn;

/**
 * 
 * A {@code Bi} object holds two references to objects, referred to as the
 * front and the back. There are no restrictions on the
 * references. One or both references may be null, and both references may point
 * to the same object. The referred objects need not be immutable or satisfy
 * any particular constraint.
 * 
 *
 * @param 
 *          The type of the object in the front slot.
 * @param 
 *          The type of the object in the back slot.
 * 
 * @since 1.0
 */
public interface Bi {

	/**
	 * @return the object in the front slot.
	 * @since 1.0
	 */
	F front( );

	/**
	 * @return the object in the back slot.
	 * @since 1.0
	 */
	B back( );
}