/* 
 * esodata - data structures and other things, of varying utility
 * Copyright 2022, Ben Culkin
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *   
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package bjc.funcdata;

/**
 * Indicates that an object can switch between immutable and mutable modes.
 * 
 * Note that this only implements 'shallow' immutability. Namely, any sub-objects
 * are not made immutable, and if the type is a collection, the elements are still
 * as mutable as they were before.
 * 
 * Implementations of this interface may choose to throw {@link ObjectFrozen} if
 * you attempt to modify a frozen object, but they may also choose not to.
 * 
 * @author Ben Culkin
 */
public interface Freezable<F extends Freezable<?>> {
	/**
	 * Freezes the internal state of this object, making it immutable.
	 * 
	 * @return True if the object is frozen, false if it couldn't be frozen.
	 */
	public boolean freeze();
	/**
	 * Thaws the internal state of this object, making it mutable.
	 * 
	 * @return True if the object is thawed, false if it couldn't be thawed.
	 */
	public boolean thaw();

	/**
	 * 'Deep-freeze' this object, making it immutable and disabling the ability to
	 * thaw it.
	 * 
	 * @return True if the object was deep-frozen, false if that couldn't happen.
	 */
	default boolean deepFreeze() {
		return false;
	}
	
	/**
	 * Check if this object can be frozen.
	 * 
	 * @return Whether or not the object can be frozen.
	 */
	default boolean canFreeze() {
		return false;
	}
	
	/**
	 * Checks if this object can be thawed.
	 * 
	 * @return Whether or not the object can be thawed.
	 */
	default boolean canThaw() {
		return false;
	}
	
	/**
	 * Determines if this object is frozen.
	 * 
	 * @return True if the object is frozen, false if the object is thawed.
	 */
	public boolean isFrozen();
	

	/**
	 * Determines if this object is thawed.
	 * 
	 * @return True if the object is thawed, false if the object is thawed.
	 */
	default boolean isThawed() {
		return !isFrozen();
	}
	
	/**
	 * Clone this object in a thawed state.
	 * 
	 * @return A thawed clone of this object
	 * 
	 * @throws CloneNotSupportedException If the underlying object doesn't support cloning
	 */
	default F cloneAsThawed() throws CloneNotSupportedException {
		throw new CloneNotSupportedException();
	}
}