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package cuchaz.enigma.gui.util;
import com.google.common.collect.Queues;
import java.util.Deque;
public class History<T> {
private final Deque<T> previous = Queues.newArrayDeque();
private final Deque<T> next = Queues.newArrayDeque();
private T current;
public History(T initial) {
current = initial;
}
public T getCurrent() {
return current;
}
public void push(T value) {
previous.addLast(current);
current = value;
next.clear();
}
public void replace(T value) {
current = value;
}
public boolean canGoBack() {
return !previous.isEmpty();
}
public T goBack() {
next.addFirst(current);
current = previous.removeLast();
return current;
}
public boolean canGoForward() {
return !next.isEmpty();
}
public T goForward() {
previous.addLast(current);
current = next.removeFirst();
return current;
}
}
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