package org.hamcrest.text;
import static org.hamcrest.core.AnyOf.anyOf;
import static org.hamcrest.core.IsNull.nullValue;
import java.util.regex.Pattern;
import org.hamcrest.Description;
import org.hamcrest.Factory;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeMatcher;
/**
* Matches blank Strings (and null).
*/
public final class IsBlankString extends TypeSafeMatcher<String> {
private static final IsBlankString BLANK_INSTANCE = new IsBlankString();
@SuppressWarnings("unchecked")
private static final Matcher<String> NULL_OR_BLANK_INSTANCE = anyOf(nullValue(), BLANK_INSTANCE);
private static final Pattern REGEX_WHITESPACE = Pattern.compile("\\s*");
private IsBlankString() { }
@Override
public boolean matchesSafely(String item) {
return REGEX_WHITESPACE.matcher(item).matches();
}
@Override
public void describeTo(Description description) {
description.appendText("a blank string");
}
/**
* Creates a matcher of {@link String} that matches when the examined string contains
* zero or more whitespace characters and nothing else.
* <p/>
* For example:
* <pre>assertThat(" ", is(blankString()))</pre>
*/
@Factory
public static Matcher<String> blankString() {
return BLANK_INSTANCE;
}
/**
* Creates a matcher of {@link String} that matches when the examined string is <code>null</code>, or
* contains zero or more whitespace characters and nothing else.
* <p/>
* For example:
* <pre>assertThat(((String)null), is(blankOrNullString()))</pre>
*
*/
@Factory
public static Matcher<String> blankOrNullString() {
return NULL_OR_BLANK_INSTANCE;
}
}