aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.xml.internal.bind.v2.util;
aoqi@0: 
aoqi@0: import java.util.Iterator;
aoqi@0: import java.util.Map;
aoqi@0: import java.util.NoSuchElementException;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * {@link Iterator} that walks over a map of maps.
aoqi@0:  *
aoqi@0:  * @author Kohsuke Kawaguchi
aoqi@0:  * @since 2.0
aoqi@0:  */
aoqi@0: public final class FlattenIterator<T> implements Iterator<T> {
aoqi@0: 
aoqi@0:     private final Iterator<? extends Map<?,? extends T>> parent;
aoqi@0:     private Iterator<? extends T> child = null;
aoqi@0:     private T next;
aoqi@0: 
aoqi@0:     public FlattenIterator( Iterable<? extends Map<?,? extends T>> core ) {
aoqi@0:         this.parent = core.iterator();
aoqi@0:     }
aoqi@0: 
aoqi@0: 
aoqi@0:     public void remove() {
aoqi@0:         throw new UnsupportedOperationException();
aoqi@0:     }
aoqi@0: 
aoqi@0:     public boolean hasNext() {
aoqi@0:         getNext();
aoqi@0:         return next!=null;
aoqi@0:     }
aoqi@0: 
aoqi@0:     public T next() {
aoqi@0:         T r = next;
aoqi@0:         next = null;
aoqi@0:         if(r==null)
aoqi@0:             throw new NoSuchElementException();
aoqi@0:         return r;
aoqi@0:     }
aoqi@0: 
aoqi@0:     private void getNext() {
aoqi@0:         if(next!=null)  return;
aoqi@0: 
aoqi@0:         if(child!=null && child.hasNext()) {
aoqi@0:             next = child.next();
aoqi@0:             return;
aoqi@0:         }
aoqi@0:         // child is empty
aoqi@0:         if(parent.hasNext()) {
aoqi@0:             child = parent.next().values().iterator();
aoqi@0:             getNext();
aoqi@0:         }
aoqi@0:         // else
aoqi@0:         //      no more object
aoqi@0:     }
aoqi@0: }