1 /*
2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 package com.sun.tools.sjavac.options;
27 
28 import java.util.Iterator;
29 
30 /**
31  *  <p><b>This is NOT part of any supported API.
32  *  If you write code that depends on this, you do so at your own risk.
33  *  This code and its internal interfaces are subject to change or
34  *  deletion without notice.</b>
35  */
36 public class ArgumentIterator implements Iterator<String> {
37 
38     /** The underlying argument iterator */
39     private Iterator<String> iter;
40 
41     /** Extra state used to implement peek and current */
42     private String current;
43     private String buffered;
44 
ArgumentIterator(Iterable<String> iter)45     public ArgumentIterator(Iterable<String> iter) {
46         this.iter = iter.iterator();
47     }
48 
49     @Override
hasNext()50     public boolean hasNext() {
51         return buffered != null || iter.hasNext();
52     }
53 
54     @Override
next()55     public String next() {
56         fillBuffer();
57         current = buffered;
58         buffered = null;
59         return current;
60     }
61 
62     /**
63      * @return the last element returned by next() (or {@code null} if next has
64      * never been invoked on this iterator).
65      */
current()66     public String current() {
67         return current;
68     }
69 
70     /** Can't remove current element, since we may have buffered it. */
71     @Override
remove()72     public void remove() {
73         throw new UnsupportedOperationException();
74     }
75 
76     /**
77      * @return Returns the next element without advancing the iterator
78      */
peek()79     public String peek() {
80         fillBuffer();
81         return buffered;
82     }
83 
fillBuffer()84     private void fillBuffer() {
85         if (buffered == null && iter.hasNext())
86             buffered = iter.next();
87     }
88 
89 }
90