com.sun.xml.bind.v2.util.FlattenIterator Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.xml.bind.v2.util;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
/**
* {@link Iterator} that walks over a map of maps.
*
* @author Kohsuke Kawaguchi
* @since 2.0
*/
public final class FlattenIterator implements Iterator {
private final Iterator> parent;
private Iterator child = null;
private T next;
public FlattenIterator( Iterable> core ) {
this.parent = core.iterator();
}
public void remove() {
throw new UnsupportedOperationException();
}
public boolean hasNext() {
getNext();
return next!=null;
}
public T next() {
T r = next;
next = null;
if(r==null)
throw new NoSuchElementException();
return r;
}
private void getNext() {
if(next!=null) return;
if(child!=null && child.hasNext()) {
next = child.next();
return;
}
// child is empty
if(parent.hasNext()) {
child = parent.next().values().iterator();
getNext();
}
// else
// no more object
}
}