1package eu.siacs.conversations.crypto.sasl;
 2
 3import java.util.ArrayList;
 4import java.util.Arrays;
 5import java.util.Iterator;
 6import java.util.List;
 7import java.util.NoSuchElementException;
 8
 9/** A tokenizer for GS2 header strings */
10public final class Tokenizer implements Iterator<String>, Iterable<String> {
11    private final List<String> parts;
12    private int index;
13
14    public Tokenizer(final byte[] challenge) {
15        final String challengeString = new String(challenge);
16        parts = new ArrayList<>(Arrays.asList(challengeString.split(",")));
17        // Trim parts.
18        for (int i = 0; i < parts.size(); i++) {
19            parts.set(i, parts.get(i).trim());
20        }
21        index = 0;
22    }
23
24    /**
25     * Returns true if there is at least one more element, false otherwise.
26     *
27     * @see #next
28     */
29    @Override
30    public boolean hasNext() {
31        return parts.size() != index + 1;
32    }
33
34    /**
35     * Returns the next object and advances the iterator.
36     *
37     * @return the next object.
38     * @throws java.util.NoSuchElementException if there are no more elements.
39     * @see #hasNext
40     */
41    @Override
42    public String next() {
43        if (hasNext()) {
44            return parts.get(index++);
45        } else {
46            throw new NoSuchElementException("No such element. Size is: " + parts.size());
47        }
48    }
49
50    /**
51     * Removes the last object returned by {@code next} from the collection. This method can only be
52     * called once between each call to {@code next}.
53     *
54     * @throws UnsupportedOperationException if removing is not supported by the collection being
55     *     iterated.
56     * @throws IllegalStateException if {@code next} has not been called, or {@code remove} has
57     *     already been called after the last call to {@code next}.
58     */
59    @Override
60    public void remove() {
61        if (index <= 0) {
62            throw new IllegalStateException(
63                    "You can't delete an element before first next() method call");
64        }
65        parts.remove(--index);
66    }
67
68    /**
69     * Returns an {@link java.util.Iterator} for the elements in this object.
70     *
71     * @return An {@code Iterator} instance.
72     */
73    @Override
74    public Iterator<String> iterator() {
75        return parts.iterator();
76    }
77}