src/main/java/org/junit/matchers/JUnitMatchers.java

package org.junit.matchers;

import org.hamcrest.Matcher;
import org.junit.internal.matchers.CombinableMatcher;
import org.junit.internal.matchers.Each;
import org.junit.internal.matchers.IsCollectionContaining;
import org.junit.internal.matchers.StringContains;

/**
 * Convenience import class: these are useful matchers for use with the assertThat method, but they are
 * not currently included in the basic CoreMatchers class from hamcrest.
 */
public class JUnitMatchers {
	/**
	 * @param element
	 * @return A matcher matching any collection containing element
	 */
	public static <T> org.hamcrest.Matcher<java.lang.Iterable<T>> hasItem(T element) {
		return IsCollectionContaining.hasItem(element);
	}

	/**
	 * @param elementMatcher
	 * @return A matcher matching any collection containing an element matching elementMatcher
	 */
	public static <T> org.hamcrest.Matcher<java.lang.Iterable<T>> hasItem(org.hamcrest.Matcher<? extends T> elementMatcher) {
		return IsCollectionContaining.<T>hasItem(elementMatcher);
	}

	/**
	 * @param elements
	 * @return A matcher matching any collection containing every element in elements
	 */
	public static <T> org.hamcrest.Matcher<java.lang.Iterable<T>> hasItems(T... elements) {
		return IsCollectionContaining.hasItems(elements);
	}

	/**
	 * @param elementMatchers
	 * @return A matcher matching any collection containing at least one element that matches 
	 *         each matcher in elementMatcher (this may be one element matching all matchers,
	 *         or different elements matching each matcher)
	 */
	public static <T> org.hamcrest.Matcher<java.lang.Iterable<T>> hasItems(org.hamcrest.Matcher<? extends T>... elementMatchers) {
		return IsCollectionContaining.<T>hasItems(elementMatchers);
	}

	/**
	 * @param elementMatcher
	 * @return A matcher matching any collection in which every element matches elementMatcher
	 */
	public static <T> Matcher<Iterable<T>> everyItem(final Matcher<T> elementMatcher) {
		return Each.each(elementMatcher);
	}

	/**
	 * @param substring
	 * @return a matcher matching any string that contains substring
	 */
	public static org.hamcrest.Matcher<java.lang.String> containsString(java.lang.String substring) {
		return StringContains.containsString(substring);
	}
	
	/**
	 * This is useful for fluently combining matchers that must both pass.  For example:
	 * <pre>
	 *   assertThat(string, both(containsString("a")).and(containsString("b")));
	 * </pre>
	 */
	public static <T> CombinableMatcher<T> both(Matcher<T> matcher) {
		return new CombinableMatcher<T>(matcher);
	}
	
	/**
	 * This is useful for fluently combining matchers where either may pass, for example:
	 * <pre>
	 *   assertThat(string, either(containsString("a")).or(containsString("b")));
	 * </pre>
	 */
	public static <T> CombinableMatcher<T> either(Matcher<T> matcher) {
		return new CombinableMatcher<T>(matcher);
	}
}