/*
* 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.history.changeset;
import com.google.common.base.Function;
import com.google.common.collect.Iterators;
import com.sk89q.worldedit.BlockVector;
import com.sk89q.worldedit.blocks.BaseBlock;
import com.sk89q.worldedit.history.change.BlockChange;
import com.sk89q.worldedit.history.change.Change;
import com.sk89q.worldedit.util.collection.TupleArrayList;
import java.util.ArrayList;
import java.util.Iterator;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Map.Entry;
/**
* An extension of {@link ArrayListHistory} that stores {@link BlockChange}s
* separately in two {@link ArrayList}s.
*
* <p>Whether this is a good idea or not is highly questionable, but this class
* exists because this is how history was implemented in WorldEdit for
* many years.</p>
*/
public class BlockOptimizedHistory extends ArrayListHistory {
private final TupleArrayList<BlockVector, BaseBlock> previous = new TupleArrayList<BlockVector, BaseBlock>();
private final TupleArrayList<BlockVector, BaseBlock> current = new TupleArrayList<BlockVector, BaseBlock>();
@Override
public void add(Change change) {
checkNotNull(change);
if (change instanceof BlockChange) {
BlockChange blockChange = (BlockChange) change;
BlockVector position = blockChange.getPosition();
previous.put(position, blockChange.getPrevious());
current.put(position, blockChange.getCurrent());
} else {
super.add(change);
}
}
@Override
public Iterator<Change> forwardIterator() {
return Iterators.concat(
super.forwardIterator(),
Iterators.transform(current.iterator(), createTransform()));
}
@Override
public Iterator<Change> backwardIterator() {
return Iterators.concat(
super.backwardIterator(),
Iterators.transform(previous.iterator(true), createTransform()));
}
@Override
public int size() {
return super.size() + previous.size();
}
/**
* Create a function that transforms each entry from the double array lists' iterator
* into an {@link Change}.
*
* @return a function
*/
private Function<Entry<BlockVector, BaseBlock>, Change> createTransform() {
return new Function<Entry<BlockVector, BaseBlock>, Change>() {
@Override
public Change apply(Entry<BlockVector, BaseBlock> entry) {
return new BlockChange(entry.getKey(), entry.getValue(), entry.getValue());
}
};
}
}