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package org.scijava.menu;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

import org.scijava.module.ModuleInfo;

/**
 * Recursive iterator for {@link ShadowMenu} hierarchies.
 * 
 * @author Curtis Rueden
 */
public class ShadowMenuIterator implements Iterator<ModuleInfo> {

	private final ShadowMenu node;
	private final List<ShadowMenuIterator> childIterators;
	private int index;

	public ShadowMenuIterator(final ShadowMenu node) {
		this.node = node;
		final List<ShadowMenu> children = node.getChildren();
		childIterators = new ArrayList<>();
		for (final ShadowMenu child : children) {
			childIterators.add(new ShadowMenuIterator(child));
		}
		index = node.getModuleInfo() == null ? 0 : -1;
	}

	@Override
	public boolean hasNext() {
		return index < childIterators.size();
	}

	@Override
	public ModuleInfo next() {
		if (!hasNext()) throw new NoSuchElementException();
		if (index < 0) {
			index++;
			return node.getModuleInfo();
		}
		final ShadowMenuIterator iter = childIterators.get(index);
		final ModuleInfo next = iter.next();
		if (!iter.hasNext()) index++;
		return next;
	}

	@Override
	public void remove() {
		throw new UnsupportedOperationException();
	}

}
