001 /* Copyright (c) 2000-2006 hamcrest.org
002 */
003 package org.hamcrest;
004
005 /**
006 * A matcher over acceptable values.
007 * A matcher is able to describe itself to give feedback when it fails.
008 * <p/>
009 * Matcher implementations should <b>NOT directly implement this interface</b>.
010 * Instead, <b>extend</b> the {@link BaseMatcher} abstract class,
011 * which will ensure that the Matcher API can grow to support
012 * new features and remain compatible with all Matcher implementations.
013 * <p/>
014 * For easy access to common Matcher implementations, use the static factory
015 * methods in {@link CoreMatchers}.
016 * <p/>
017 * N.B. Well designed matchers should be immutable.
018 *
019 * @see CoreMatchers
020 * @see BaseMatcher
021 */
022 public interface Matcher<T> extends SelfDescribing {
023
024 /**
025 * Evaluates the matcher for argument <var>item</var>.
026 * <p/>
027 * This method matches against Object, instead of the generic type T. This is
028 * because the caller of the Matcher does not know at runtime what the type is
029 * (because of type erasure with Java generics). It is down to the implementations
030 * to check the correct type.
031 *
032 * @param item the object against which the matcher is evaluated.
033 * @return <code>true</code> if <var>item</var> matches, otherwise <code>false</code>.
034 *
035 * @see BaseMatcher
036 */
037 boolean matches(Object item);
038
039 /**
040 * Generate a description of why the matcher has not accepted the item.
041 * The description will be part of a larger description of why a matching
042 * failed, so it should be concise.
043 * This method assumes that <code>matches(item)</code> is false, but
044 * will not check this.
045 *
046 * @param item The item that the Matcher has rejected.
047 * @param mismatchDescription
048 * The description to be built or appended to.
049 */
050 void describeMismatch(Object item, Description mismatchDescription);
051
052 /**
053 * This method simply acts a friendly reminder not to implement Matcher directly and
054 * instead extend BaseMatcher. It's easy to ignore JavaDoc, but a bit harder to ignore
055 * compile errors .
056 *
057 * @see Matcher for reasons why.
058 * @see BaseMatcher
059 * @deprecated to make
060 */
061 @Deprecated
062 void _dont_implement_Matcher___instead_extend_BaseMatcher_();
063 }