org.eclipse.xtext.nodemodel.util.NodeIterator.java Source code

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Here is the source code for org.eclipse.xtext.nodemodel.util.NodeIterator.java

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/*******************************************************************************
 * Copyright (c) 2010 itemis AG (http://www.itemis.eu) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.eclipse.xtext.nodemodel.util;

import java.util.NoSuchElementException;

import org.eclipse.xtext.nodemodel.BidiIterator;
import org.eclipse.xtext.nodemodel.INode;

import com.google.common.collect.UnmodifiableIterator;

/**
 * @author Sebastian Zarnekow - Initial contribution and API
 */
public class NodeIterator extends UnmodifiableIterator<INode> implements BidiIterator<INode> {

    private final INode startWith;
    private INode lastReturned;

    public NodeIterator(INode startWith) {
        this.startWith = startWith;
    }

    @Override
    public boolean hasNext() {
        return lastReturned == null || lastReturned.hasNextSibling();
    }

    @Override
    public INode next() {
        if (!hasNext())
            throw new NoSuchElementException();
        if (lastReturned == null) {
            lastReturned = startWith;
        } else {
            lastReturned = lastReturned.getNextSibling();
        }
        return lastReturned;
    }

    @Override
    public boolean hasPrevious() {
        return lastReturned == null || lastReturned.hasPreviousSibling();
    }

    @Override
    public INode previous() {
        if (!hasPrevious())
            throw new NoSuchElementException();
        if (lastReturned == null) {
            if (startWith.getParent() != null) {
                lastReturned = startWith.getParent().getLastChild();
            } else {
                lastReturned = startWith;
            }
        } else {
            lastReturned = lastReturned.getPreviousSibling();
        }
        return lastReturned;
    }

}