1
2package org.hamcrest.text;
3
4import org.hamcrest.Description;
5import org.hamcrest.Matcher;
6import org.hamcrest.TypeSafeMatcher;
7
8import static org.hamcrest.core.AnyOf.anyOf;
9import static org.hamcrest.core.IsNull.nullValue;
10
11/**
12 * Matches empty Strings (and null).
13 */
14public final class IsEmptyString extends TypeSafeMatcher<String> {
15    private static final IsEmptyString INSTANCE = new IsEmptyString();
16    @SuppressWarnings("unchecked")
17    private static final Matcher<String> NULL_OR_EMPTY_INSTANCE = anyOf(nullValue(), INSTANCE);
18
19    private IsEmptyString() { }
20
21    @Override
22    public boolean matchesSafely(String item) {
23        return item.equals("");
24    }
25
26    @Override
27    public void describeTo(Description description) {
28        description.appendText("an empty string");
29    }
30
31    /**
32     * Creates a matcher of {@link String} that matches when the examined string has zero length.
33     * For example:
34     * <pre>assertThat("", isEmptyString())</pre>
35     *
36     * @deprecated use is(emptyString()) instead
37     */
38    @Deprecated
39    public static Matcher<String> isEmptyString() {
40        return emptyString();
41    }
42
43    /**
44     * Creates a matcher of {@link String} that matches when the examined string has zero length.
45     * For example:
46     * <pre>assertThat("", is(emptyString()))</pre>
47     *
48     */
49    public static Matcher<String> emptyString() {
50        return INSTANCE;
51    }
52
53    /**
54     * Creates a matcher of {@link String} that matches when the examined string is <code>null</code>, or
55     * has zero length.
56     * For example:
57     * <pre>assertThat(((String)null), isEmptyOrNullString())</pre>
58     *
59     * @deprecated use is(emptyOrNullString()) instead
60     *
61     */
62    @Deprecated
63    public static Matcher<String> isEmptyOrNullString() {
64        return emptyOrNullString();
65    }
66
67    /**
68     * Creates a matcher of {@link String} that matches when the examined string is <code>null</code>, or
69     * has zero length.
70     * For example:
71     * <pre>assertThat(((String)null), is(emptyOrNullString()))</pre>
72     *
73     */
74    public static Matcher<String> emptyOrNullString() {
75        return NULL_OR_EMPTY_INSTANCE;
76    }
77}
78