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 public class ArgumentIterator implements Iterator<String> {

    31 

    32     /** The underlying argument iterator */

    33     private Iterator<String> iter;

    34 

    35     /** Extra state used to implement peek and current */

    36     private String current;

    37     private String buffered;

    38 

    39     public ArgumentIterator(Iterable<String> iter) {

    40         this.iter = iter.iterator();

    41     }

    42 

    43     @Override

    44     public boolean hasNext() {

    45         return buffered != null || iter.hasNext();

    46     }

    47 

    48     @Override

    49     public String next() {

    50         fillBuffer();

    51         current = buffered;

    52         buffered = null;

    53         return current;

    54     }

    55 

    56     /**

    57      * @return the last element returned by next() (or {@code null} if next has

    58      * never been invoked on this iterator).

    59      */

    60     public String current() {

    61         return current;

    62     }

    63 

    64     /** Can't remove current element, since we may have buffered it. */

    65     @Override

    66     public void remove() {

    67         throw new UnsupportedOperationException();

    68     }

    69 

    70     /**

    71      * @return Returns the next element without advancing the iterator

    72      */

    73     public String peek() {

    74         fillBuffer();

    75         return buffered;

    76     }

    77 

    78     private void fillBuffer() {

    79         if (buffered == null && iter.hasNext())

    80             buffered = iter.next();

    81     }

    82 

    83 }