package com.planet_ink.coffee_mud.core.collections; import java.util.Collection; import java.util.Enumeration; import java.util.Iterator; import java.util.LinkedList; import java.util.NoSuchElementException; import java.util.Vector; /* Copyright 2010-2019 Bo Zimmerman 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. */ public class MultiIterator<K> implements Iterator<K> { private final LinkedList<Iterator<K>> iters=new LinkedList<Iterator<K>>(); private volatile Iterator<K> iter=null; public MultiIterator(final Iterator<K>[] esets) { if((esets==null)||(esets.length==0)) return; for(final Iterator<K> I : esets) iters.add(I); } public MultiIterator(final Collection<Iterator<K>> esets) { if((esets==null)||(esets.size()==0)) return; iters.addAll(esets); for(final Iterator<K> I : esets) iters.add(I); } public MultiIterator(final Iterable<K>[] esets) { if((esets==null)||(esets.length==0)) return; for(final Iterable<K> I : esets) iters.add(I.iterator()); } public MultiIterator(final Iterable<? extends Iterable<K>> esets) { if(esets==null) return; for(final Iterable<K> I : esets) iters.add(I.iterator()); } public MultiIterator() { } public void add(final Iterator<K> eset) { iters.add(eset); } @Override public boolean hasNext() { boolean hasNext = (iter != null) && iter.hasNext(); while(!hasNext) { if(iters.size()==0) { iter=null; return false; } iter=iters.removeFirst(); hasNext = (iter != null) && iter.hasNext(); } return hasNext; } @Override public K next() { if(!hasNext()) throw new NoSuchElementException(); return iter.next(); } @Override public void remove() { if(iter != null) iter.remove(); } }