/* * Copyright 2003-2010 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package groovy.util.slurpersupport; import java.util.Iterator; /** * Helper class for iterating through nodes. * * @author John Wilson */ public abstract class NodeIterator implements Iterator { private static final Object DELAYED_INIT = new Object(); private final Iterator iter; private Object nextNode; public NodeIterator(final Iterator iter) { this.iter = iter; this.nextNode = DELAYED_INIT; } private void initNextNode(){ if (nextNode==DELAYED_INIT) nextNode = getNextNode(iter); } public boolean hasNext() { initNextNode(); return this.nextNode != null; } public Object next() { initNextNode(); try { return this.nextNode; } finally { this.nextNode = getNextNode(this.iter); } } public void remove() { throw new UnsupportedOperationException(); } protected abstract Object getNextNode(final Iterator iter); }