1 package org.hamcrest; 2 3 /** 4 * A Condition implements part of a multi-step match. We sometimes need to write matchers 5 * that have a sequence of steps, where each step depends on the result of the previous 6 * step and we can stop processing as soon as a step fails. These classes provide 7 * infrastructure for writing such a sequence. 8 * 9 * Based on https://github.com/npryce/maybe-java 10 * @author Steve Freeman 2012 http://www.hamcrest.com 11 */ 12 13 public abstract class Condition<T> { 14 public static final NotMatched<Object> NOT_MATCHED = new NotMatched<Object>(); 15 16 public interface Step<I, O> { apply(I value, Description mismatch)17 Condition<O> apply(I value, Description mismatch); 18 } 19 Condition()20 private Condition() { } 21 matching(Matcher<T> match, String message)22 public abstract boolean matching(Matcher<T> match, String message); and(Step<? super T, U> mapping)23 public abstract <U> Condition<U> and(Step<? super T, U> mapping); 24 matching(Matcher<T> match)25 public final boolean matching(Matcher<T> match) { return matching(match, ""); } then(Step<? super T, U> mapping)26 public final <U> Condition<U> then(Step<? super T, U> mapping) { return and(mapping); } 27 28 @SuppressWarnings("unchecked") notMatched()29 public static <T> Condition<T> notMatched() { 30 return (Condition<T>) NOT_MATCHED; 31 } 32 matched(final T theValue, final Description mismatch)33 public static <T> Condition<T> matched(final T theValue, final Description mismatch) { 34 return new Matched<T>(theValue, mismatch); 35 } 36 37 private static final class Matched<T> extends Condition<T> { 38 private final T theValue; 39 private final Description mismatch; 40 Matched(T theValue, Description mismatch)41 private Matched(T theValue, Description mismatch) { 42 this.theValue = theValue; 43 this.mismatch = mismatch; 44 } 45 46 @Override matching(Matcher<T> matcher, String message)47 public boolean matching(Matcher<T> matcher, String message) { 48 if (matcher.matches(theValue)) { 49 return true; 50 } 51 mismatch.appendText(message); 52 matcher.describeMismatch(theValue, mismatch); 53 return false; 54 } 55 56 @Override and(Step<? super T, U> next)57 public <U> Condition<U> and(Step<? super T, U> next) { 58 return next.apply(theValue, mismatch); 59 } 60 } 61 62 private static final class NotMatched<T> extends Condition<T> { matching(Matcher<T> match, String message)63 @Override public boolean matching(Matcher<T> match, String message) { return false; } 64 and(Step<? super T, U> mapping)65 @Override public <U> Condition<U> and(Step<? super T, U> mapping) { 66 return notMatched(); 67 } 68 } 69 } 70