70 lines
1.2 KiB
Java
70 lines
1.2 KiB
Java
package dev.kske.undoredo;
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import java.util.*;
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/**
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* @param <C> the change type to store in this change manager
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* @author Maximilian Käfer
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* @author Kai S. K. Engelbart
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* @since 0.0.1
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*/
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public final class UnlimitedChangeManager<C extends Change> implements ChangeManager<C> {
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private final List<C> changes = new LinkedList<>();
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private int index = -1;
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private int markedIndex = -1;
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@Override
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public void addChange(C change) {
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change.apply();
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changes.add(change);
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++index;
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}
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@Override
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public boolean undo() {
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if (isUndoAvailable()) {
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changes.get(index).invert().apply();
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--index;
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return true;
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}
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return false;
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}
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@Override
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public boolean redo() {
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if (isRedoAvailable()) {
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changes.get(index + 1).apply();
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++index;
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return true;
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}
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return false;
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}
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@Override
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public void mark() {
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markedIndex = index;
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}
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@Override
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public boolean isAtMarkedIndex() {
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return markedIndex == index;
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}
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@Override
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public boolean isUndoAvailable() {
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return index > -1;
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}
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@Override
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public boolean isRedoAvailable() {
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return index < changes.size() - 1;
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}
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@Override
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public List<C> getChanges() {
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return Collections.unmodifiableList(changes);
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}
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}
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