IValue.java

/*
 * Copyright 2013 Martin Smock <smock.martin@gmail.com>
 * 
 * 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 li.strolch.model.timevalue;

/**
 * A value object defining some basic algebraic operations. Mathematically speaking {@link IValue} objects define a
 * group with a addition operation.
 *
 * @author Martin Smock <smock.martin@gmail.com>
 *
 * @param <T>
 *            any object for which a (generalized) add operation can be defined.
 */
public interface IValue<T> {

	/**
	 * @return the type of this {@link IValue}
	 */
	String getType();

	/**
	 * @return the backing value
	 */
	T getValue();

	/**
	 * @return a value with the backing value added to the argument value
	 */
	IValue<T> add(T o);

	/**
	 * @return true, if the backing values match.
	 */
	boolean matches(IValue<T> other);

	/**
	 * @return the inverse value, such that add(value.getInverse()) returns the neutral element of the group
	 */
	IValue<T> getInverse();

	/**
	 * @return a copy of this
	 */
	IValue<T> getCopy();

	/**
	 * @return this value in string representation
	 */
	String getValueAsString();
}