1/*
2* Conditions Of Use
3*
4* This software was developed by employees of the National Institute of
5* Standards and Technology (NIST), an agency of the Federal Government.
6* Pursuant to title 15 Untied States Code Section 105, works of NIST
7* employees are not subject to copyright protection in the United States
8* and are considered to be in the public domain.  As a result, a formal
9* license is not needed to use the software.
10*
11* This software is provided by NIST as a service and is expressly
12* provided "AS IS."  NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
13* OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
14* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
15* AND DATA ACCURACY.  NIST does not warrant or make any representations
16* regarding the use of the software or the results thereof, including but
17* not limited to the correctness, accuracy, reliability or usefulness of
18* the software.
19*
20* Permission to use this software is contingent upon your acceptance
21* of the terms of this agreement
22*
23* .
24*
25*/
26package gov.nist.javax.sip.message;
27
28import gov.nist.javax.sip.header.*;
29import java.util.ListIterator;
30import java.util.NoSuchElementException;
31
32/**
33 * Iterator over lists of headers. Allows for uniform removal handling for singleton headers.
34 * @author M. Ranganathan
35 * @version 1.2 $Revision: 1.8 $ $Date: 2009/07/17 18:57:53 $
36 * @since 1.1
37 */
38public class HeaderIterator implements ListIterator {
39    private boolean toRemove;
40    private int index;
41    private SIPMessage sipMessage;
42    private SIPHeader sipHeader;
43
44    protected HeaderIterator(SIPMessage sipMessage, SIPHeader sipHeader) {
45        this.sipMessage = sipMessage;
46        this.sipHeader = sipHeader;
47    }
48
49    public Object next() throws NoSuchElementException {
50        if (sipHeader == null || index == 1)
51            throw new NoSuchElementException();
52        toRemove = true;
53        index = 1;
54        return (Object) sipHeader;
55    }
56
57    public Object previous() throws NoSuchElementException {
58        if (sipHeader == null || index == 0)
59            throw new NoSuchElementException();
60        toRemove = true;
61        index = 0;
62        return (Object) sipHeader;
63    }
64
65    public int nextIndex() {
66        return 1;
67    }
68
69    public int previousIndex() {
70        return index == 0 ? -1 : 0;
71    }
72
73    public void set(Object header) {
74        throw new UnsupportedOperationException();
75    }
76
77    public void add(Object header) {
78        throw new UnsupportedOperationException();
79    }
80
81    public void remove() throws IllegalStateException {
82        if (this.sipHeader == null)
83            throw new IllegalStateException();
84        if (toRemove) {
85            this.sipHeader = null;
86            this.sipMessage.removeHeader(sipHeader.getName());
87        } else {
88            throw new IllegalStateException();
89        }
90    }
91
92    public boolean hasNext() {
93        return index == 0;
94    }
95
96    public boolean hasPrevious() {
97        return index == 1;
98    }
99}
100