/*
* WorldEdit, a Minecraft world manipulation toolkit
* Copyright (C) sk89q <http://www.sk89q.com>
* Copyright (C) WorldEdit team and contributors
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.sk89q.worldedit.function.operation;
import com.sk89q.worldedit.WorldEditException;
import com.sk89q.worldedit.history.change.Change;
import com.sk89q.worldedit.history.changeset.ChangeSet;
import com.sk89q.worldedit.history.UndoContext;
import java.util.Iterator;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* Performs an undo or redo from a given {@link ChangeSet}.
*/
public class ChangeSetExecutor implements Operation {
public enum Type {UNDO, REDO}
private final Iterator<Change> iterator;
private final Type type;
private final UndoContext context;
/**
* Create a new instance.
*
* @param changeSet the change set
* @param type type of change
* @param context the undo context
*/
private ChangeSetExecutor(ChangeSet changeSet, Type type, UndoContext context) {
checkNotNull(changeSet);
checkNotNull(type);
checkNotNull(context);
this.type = type;
this.context = context;
if (type == Type.UNDO) {
iterator = changeSet.backwardIterator();
} else {
iterator = changeSet.forwardIterator();
}
}
@Override
public Operation resume(RunContext run) throws WorldEditException {
while (iterator.hasNext()) {
Change change = iterator.next();
if (type == Type.UNDO) {
change.undo(context);
} else {
change.redo(context);
}
}
return null;
}
@Override
public void cancel() {
}
/**
* Create a new undo operation.
*
* @param changeSet the change set
* @param context an undo context
* @return an operation
*/
public static ChangeSetExecutor createUndo(ChangeSet changeSet, UndoContext context) {
return new ChangeSetExecutor(changeSet, Type.UNDO, context);
}
/**
* Create a new redo operation.
*
* @param changeSet the change set
* @param context an undo context
* @return an operation
*/
public static ChangeSetExecutor createRedo(ChangeSet changeSet, UndoContext context) {
return new ChangeSetExecutor(changeSet, Type.REDO, context);
}
}