/*
* This file is part of Skript.
*
* Skript 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.
*
* Skript 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 Skript. If not, see <http://www.gnu.org/licenses/>.
*
*
* Copyright 2011-2014 Peter Güttinger
*
*/
package ch.njol.skript.classes;
import org.bukkit.event.Event;
import org.eclipse.jdt.annotation.Nullable;
import ch.njol.skript.classes.data.DefaultChangers;
import ch.njol.skript.lang.Expression;
/**
* An interface to declare changeable values. All Expressions implement something similar like this by default, but refuse any change if {@link Expression#acceptChange(ChangeMode)}
* isn't overridden.
* <p>
* Some useful Changers can be found in {@link DefaultChangers}
*
* @author Peter Güttinger
* @see DefaultChangers
* @see Expression
*/
public interface Changer<T> {
public static enum ChangeMode {
ADD, SET, REMOVE, REMOVE_ALL, DELETE, RESET;
}
/**
* Tests whether this changer supports the given mode, and if yes what type(s) it expects the elements of <code>delta</code> to be.
* <p>
* Unlike {@link Expression#acceptChange(ChangeMode)} this method must not print errors.
*
* @param mode
* @return An array of types that {@link #change(Object[], Object[], ChangeMode)} accepts as its <code>delta</code> parameter (which can be arrays to denote that multiple of
* that type are accepted), or null if the given mode is not supported. For {@link ChangeMode#DELETE} and {@link ChangeMode#RESET} this can return any non-null array to
* mark them as supported.
*/
@Nullable
public abstract Class<?>[] acceptChange(ChangeMode mode);
/**
* @param what The objects to change
* @param delta An array with one or more instances of one or more of the the classes returned by {@link #acceptChange(ChangeMode)} for the given change mode (null for
* {@link ChangeMode#DELETE} and {@link ChangeMode#RESET}). <b>This can be a Object[], thus casting is not allowed.</b>
* @param mode
* @throws UnsupportedOperationException (optional) if this method was called on an unsupported ChangeMode.
*/
public abstract void change(T[] what, @Nullable Object[] delta, ChangeMode mode);
public static abstract class ChangerUtils {
@SuppressWarnings("unchecked")
public final static <T, V> void change(final Changer<T> changer, final Object[] what, final @Nullable Object[] delta, final ChangeMode mode) {
changer.change((T[]) what, delta, mode);
}
/**
* Tests whether an expression accepts changes of a certain type. If multiple types are given it test for whether any of the types is accepted.
*
* @param e The expression to test
* @param mode The ChangeMode to use in the test
* @param types The types to test for
* @return Whether <tt>e.{@link Expression#change(Event, Object[], ChangeMode) change}(event, type[], mode)</tt> can be used or not.
*/
public final static boolean acceptsChange(final Expression<?> e, final ChangeMode mode, final Class<?>... types) {
final Class<?>[] cs = e.acceptChange(mode);
if (cs == null)
return false;
for (final Class<?> type : types) {
for (final Class<?> c : cs) {
if (c.isArray() ? c.getComponentType().isAssignableFrom(type) : c.isAssignableFrom(type))
return true;
}
}
return false;
}
}
}