64 lines
1.2 KiB
Java
64 lines
1.2 KiB
Java
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package net.filebot.util;
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import java.util.Arrays;
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import java.util.Iterator;
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import java.util.LinkedList;
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public abstract class TreeIterator<T> implements Iterator<T> {
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private final LinkedList<Iterator<T>> recursionStack = new LinkedList<Iterator<T>>();
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public TreeIterator(T... root) {
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recursionStack.push(Arrays.asList(root).iterator());
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}
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protected abstract Iterator<T> children(T node);
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@Override
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public boolean hasNext() {
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return currentIterator().hasNext();
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}
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@Override
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public T next() {
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T node = currentIterator().next();
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Iterator<T> children = children(node);
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if (children != null && children.hasNext()) {
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// step into next recursion level
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recursionStack.push(children);
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}
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return node;
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}
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private Iterator<T> currentIterator() {
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Iterator<T> iterator = recursionStack.peek();
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if (iterator.hasNext() || recursionStack.size() <= 1)
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return iterator;
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// step back one recursion level
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recursionStack.pop();
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return currentIterator();
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}
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@Override
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public void remove() {
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// can't just use remove() on current iterator, because
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// we may have stepped into the next recursion level
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throw new UnsupportedOperationException();
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}
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}
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